CN100558488C - Iron based powder for powder metallurgy - Google Patents
Iron based powder for powder metallurgy Download PDFInfo
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- CN100558488C CN100558488C CNB2005100046858A CN200510004685A CN100558488C CN 100558488 C CN100558488 C CN 100558488C CN B2005100046858 A CNB2005100046858 A CN B2005100046858A CN 200510004685 A CN200510004685 A CN 200510004685A CN 100558488 C CN100558488 C CN 100558488C
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Abstract
一种粉末冶金用铁基混合粉末，该粉末在由表面上使铜粉部分合金化而附着的雾化铁粉和优选进而雾化纯铁粉构成的铁基粉末中，至少添加石墨粉末和游离润滑剂，利用粘合剂使石墨粉末和切削性改善用粉末固定在铁基粉末表面，该铁基粉末具有如下的粒度分布，相对铁基粉末总量，粒径小于45μm的粒子为18.5质量%以下；粒径75μm以上小于150μm的粒子为46质量%以上；粒径150μm以上小于180μm的粒子小于10质量%；粒径180μm以上的粒子为0.5质量%以下。通过做成这样的粉末，可以得到压缩性好且填充性也好的粉末冶金用铁基粉末混合粉。
An iron-based mixed powder for powder metallurgy, in which at least graphite powder and free A lubricant that fixes graphite powder and machinability-improving powder on the surface of an iron-based powder with a binder, the iron-based powder having a particle size distribution of 18.5% by mass of particles with a particle diameter of less than 45 μm relative to the total amount of the iron-based powder Below; particles with a particle size of 75 μm or more and less than 150 μm are more than 46% by mass; particles with a particle size of 150 μm or more and less than 180 μm are less than 10% by mass; particles with a particle size of 180 μm or more are 0.5% by mass or less. By making such a powder, it is possible to obtain an iron-based powder mixed powder for powder metallurgy with good compressibility and good filling properties.
Description
Technical field
The present invention relates to the iron-based powder for powder metallurgy mixed powder, particularly improve the fillibility of iron-based powder mixed powder to metal mold.
Background technology
Usually, iron-based powder for powder metallurgy mixed powder (below be also referred to as the iron base powder mixture end) is in the iron-based powder as matrix, mixes alloy powder such as copper powder, graphite powder, phosphatization iron powder; Lubricants such as zinc stearate; The machinability improvement of adding is as required made with powder.But all different various powders of size, shape and density is contained at this iron base powder mixture end.For this reason, carry after mixing, pack into or unload discharge bucket, fill and during extrusion forming etc., particle distributes unevenly in mixed powder to metal mold, particle diameter, shape, chemical composition etc. are easy to generate segregation.
For example, the mixed powder of iron powder and graphite powder, by the vibration in carrying, iron powder and graphite powder freely move respectively in transport box, move, and form uneven distribution in mixed powder.The graphite powder that particularly known proportion is little floats in transport box to the surface.In addition, the iron powder of the hopper of packing into and the mixed powder of graphite powder when mobile, produce segregation in hopper.Therefore, the mixed powder of discharging from hopper is in initial stage, mid-term, the final period of discharging, and its graphite powder concentration has very big difference respectively.
Formed body is made in the mixed powder extrusion forming that produces such segregation, when carrying out sintering again when obtaining the end article sintered body, the composition change of each sintered body, so its size and intensity produces very big deviation, forms substandard products.In addition, being blended in copper powder in the iron powder, graphite powder, phosphatization iron powder etc. all is the powder littler than iron powder, so the specific area of mixed powder is increased, makes its mobile decline.And mobile is will also be to reduce the filling speed of mixed powder in the forming metal casting mold, the productive reason of reduction formed body.
As the technology that prevents such segregation, for example to open in the flat 01-219101 communique and proposed the iron base powder mixture end the spy, this powder as adhesive, makes graphite powder be attached to the iron-based powder surface with zinc stearate.In addition, present inventor etc. open in the flat 03-162502 communique the spy and have proposed a kind of method, use metallic soap class and aliphatic acid as adhesive, make alloy use powder attached to the iron-based powder surface.In addition, proposed iron base powder mixture in No. 3004800 communique of special permission, this powder uses the adhesive that does not contain metallic element, makes alloy use powder attached to the iron-based powder surface.According to the technology of putting down in writing in No. 3004800 communique of special permission, the pollution that can alleviate sintering furnace.
But the iron base powder mixture end of having taked described segregation to prevent technology particularly is used in the iron powder that atomizes the iron base powder mixture end in the iron-based powder, has problems in the fillibility of forming metal casting mold, the particularly fillibility to a narrow part.Just, when these iron base powder mixture ends are filled in the metal mold of for example gear shape, littler than other parts to a packed density of narrow crown end parts.Because the difference of the packed density that the difference at position causes may produce the difference of bringing owing to the position of size changing rate when sintering, the dimensional accuracy of goods (sintered body) is descended like this.In addition, the packed density of crown end parts low also can cause the low of crown end sintered density like this, and the strength of gear teeth is descended.Usually in gear because the stress of crown end parts effect maximum, thereby wish to improve the packed density of crown end.
And, recently from the viewpoint of the environment of considering to preserve our planet, requiring to reduce the fuel consumption of automobile etc., realize the lightweight of vehicle.Corresponding such tendency, the automobile component aspect also requires parts to develop to miniaturization.For this reason, the suffered stress of parts tends to improve, and an urgent demand has high-intensity parts.In the iron-based sintered component, if identical component, density is high more to have high intensity more, so the iron base powder mixture end of an urgent demand raw meal has good compressibility.Consider compressibility, better as the atomized iron powder of iron-based powder than reduced iron powder, but there is the problem of fillibility difference in atomized iron powder.
At such problem, the inventor opens the spy and has proposed a kind of technical scheme in the 2002-180103 communique, and the crystal boundary distribution by the control iron-based powder improves the fillibility to narrow part.But,, require further to improve fillibility along with the complicated and miniaturization of metal mold shape.
In addition,, for example open in the flat 09-267195 communique and proposed a kind of method, the iron base powder mixture end is filled in the forming metal casting mold equably the spy to the research of fill method itself.Opening the technology of putting down in writing in the flat 09-267195 communique the spy is a kind of method of filling the iron base powder mixture end equably, wherein, the conduit that gas is flowed out in the powder case is set, and uses this conduit, makes in the iron base powder mixture end layer of gas in the powder case to flow out.But, because need special device, manufacturing cost is improved in this technology.
Summary of the invention
The object of the present invention is to provide a kind of iron based powder for powder metallurgy end, this powder solves problems of the prior art effectively, has good compressibility and fillibility.
The inventor is in order to address the above problem, and to containing iron-based powder and alloy with powder or contain machinability again and improve with in the iron base powder mixture end of powder, the various factors that relates to compressibility and fillibility carries out deep research.Found that, make alloy partially-alloyed on the iron-based powder surface with the copper powder of powder, when it is adhered to, this iron-based powder is made powder with specific size distribution, can in the practical application in very narrow hole fillibility be improved significantly thus, it surpasses the degree of the value anticipation that can utilize the fillibility of carrying out in the attribute testing, that is, the mass deviation of the moulding product in the actual use is reduced significantly (to call the real machine fillibility in the following text).
The present invention is on the basis of described viewpoint, has carried out further investigation and has finished.Just, main contents of the present invention are as follows:
(1) a kind of iron base powder mixture end, contain iron-based powder, powdered graphite, reach free lubricant, perhaps contain machinability improvement powder again, the aforementioned machinability improvement of aforementioned powdered graphite and (during interpolation) utilizes adhesive on aforementioned iron-based powder surface with powder, it is characterized in that, aforementioned iron-based powder is by make copper powder partially-alloyed and atomized iron powder that adhere to constitutes on the surface, perhaps more preferably contain the atomizing straight iron powder, and the size distribution that satisfies aforementioned iron-based powder is below the particle 18.5 quality % of particle diameter less than 45 μ m; More than the above particle 46 quality % of particle diameter 75 μ m less than 150 μ m; The above particle less than 180 μ m of particle diameter 150 μ m less than 10 less than quality %; Below the particle 0.5 quality % more than the particle diameter 180 μ m.
Here, the apparent density of aforementioned iron-based powder is 2.85Mg/m
3More than.
(2) as the iron based powder for powder metallurgy end in (1), it is characterized in that, contain the copper of 0.5～30 quality %.
(3) as the iron based powder for powder metallurgy end in (1) or (2), it is characterized in that, aforementioned copper powder is set at the copper powder of average grain diameter 20～100 μ m.
(4) as the iron based powder for powder metallurgy end in any one in (1) to (3), it is characterized in that the degree of adhering to that makes aforementioned powdered graphite is more than 85%.
(5) as the iron based powder for powder metallurgy end in any one in (1) to (4), it is characterized in that, aforementioned relatively iron-based powder and powdered graphite and (during interpolation) machinability are improved total amount 100 weight portions with powder, and the addition that makes the aforementioned adhesion agent is 0.1～1.0 weight portion.
(6) as the iron based powder for powder metallurgy end in (5), it is characterized in that the aforementioned adhesion agent is to be selected from the molten mixture of stearic acid, oleamide, stearic amide, stearic amide and ethylene bis stearic acid amide and in the ethylene bis stearic acid amide one or more.
As the iron based powder for powder metallurgy end in (5), it is characterized in that (7) the aforementioned adhesion agent is the molten mixture that is selected from least a and zinc stearate in oleic acid, bobbin oil, the turbine oil.
(8) as the iron based powder for powder metallurgy end in any one in (1) to (7), it is characterized in that, aforementioned relatively iron-based powder and powdered graphite and (during interpolation) machinability are improved total amount 100 weight portions with powder, and the content of aforementioned free lubricant is 0.1～0.5 weight portion.
As the powder used in metallurgy iron-based mixture in (8), it is characterized in that (9) aforementioned free lubricant contains and is selected from least a in thermoplastic resin cosmetics, zinc stearate, the lithium stearate; Perhaps also contain the molten mixture that is selected from stearic acid, oleamide, stearic amide, stearic amide and ethylene bis stearic acid amide, ethylene bis stearic acid amide, molecular weight below 10,000 polyethylene and ethylene bis stearic acid amide and the poly molten mixture of molecular weight below 10,000 at least a.
(10) as the powder used in metallurgy iron-based mixture in (9), it is characterized in that, the relative aforementioned thermoplastic resin powder of aforementioned thermoplastic resin powder total amount, make its contain 50 quality % above be selected from least a in monomer acrylate, methacrylate and the aromatic ethylene compound, and an average grain diameter is 0.03～5 μ m, the aggegation average grain diameter is 5～50 μ m, and the mean molecule quantity that solution specific viscosity method is measured is 30,000～5,000,000.
Description of drawings
Fig. 1 schematically shows the key diagram of fillibility evaluation with the experimental rig summary.
Fig. 2 is the key diagram of the definition of expression primary particle particle diameter, agglutination particle particle diameter.
Fig. 3 A is the key diagram (vertical view) that schematically shows the shape of the spur gear that uses in the real machine fillibility is estimated.
Fig. 3 B is the key diagram (side view) that schematically shows the shape of the spur gear that uses in the real machine fillibility is estimated.
The specific embodiment
Iron based powder for powder metallurgy of the present invention end is the iron base powder mixture end of containing iron-based powder, powdered graphite, free lubricant.In addition, also can mix machinability in the iron based powder for powder metallurgy of the present invention end improves and uses powder.In addition, adhesive also can be added in iron based powder for powder metallurgy of the present invention end, and the machinability when this adhesive is used for powdered graphite and interpolation is improved the surface that is fixed on iron-based powder with powder.If have aforementioned alloy in addition to need to add, do not get rid of use, but do not need substantially with powder and additive.
The preferred 3.1Mg/m of apparent density at iron based powder for powder metallurgy of the present invention end
3More than.
The iron-based powder that the present invention uses preferably uses the atomizing straight iron powder and makes the mixed powder of its atomized iron powder that adheres at atomizing straight iron powder surface portion alloying copper powder.Raw material as iron-based powder passes through to use the atomizing straight iron powder, further improves the compressibility at iron base powder mixture end.
In addition, also can use separately, still, mix the atomizing straight iron powder that copper powder is adhered in indiffusion, can further improve the real machine fillibility by adding at atomizing straight iron powder surface portion alloying copper powder and make its atomized iron powder that adheres to.Relative iron-based powder integral body, the suitable combined amount that the atomizing straight iron powder of copper powder is adhered in indiffusion is below 99%, especially preferably mixes 50～90 quality %.
Copper powder that the present invention mainly uses, partially-alloyed makes its atomized iron powder that adheres to, and is raw material with water atomization state iron powder preferably, carries out copper powder simultaneously and adheres to processing and final reduction processing, makes.
Water atomization state iron powder is a kind of also as the raw material of atomizing straight iron powder, the unreduced iron powder that adopts water atomization to make from molten metal.Water atomization state iron powder preferably contains C: less than 0.3 quality %, O:0.3～0.9 quality %.Under the situation of C content in the iron powder, can further improve the compressibility of the iron powder that obtains after final reduction is handled less than 0.3 quality %.In addition when O content be 0.3 quality % when above, when the partially-alloyed heat treatment of carrying out that is used for copper powder, exceedingly do not promote the diffusion of Cu, so can suppress the solid molten sclerosis of Cu, further improve the compressibility of iron powder.
As the unavoidable impurities beyond C, the O of water atomization state iron powder, can allow to contain the following N of 0.2 quality % following Si, 0.2 quality % following Mn, 0.01 quality % following P, 0.01 quality % following S, 0.03 quality % following Cr, 50 quality ppm etc.
C and O after final reduction is handled are reduced to 0.0005～0.005 quality %, 0.01～0.3 quality % respectively, and other impurity does not almost change.
In the present invention, with alloy with the copper powder of powder, partially-alloyed at atomized iron powder the surface and it is adhered to.By on the atomized iron powder surface, it being adhered to copper powder is partially-alloyed, can significantly improve the real machine fillibility at iron base powder mixture end.In addition, the partially-alloyed attachment techniques of copper powder itself, prevent technology as replacing the segregation of adhering to that adhesive carries out etc., can open clear 53-92306 communique by the spy, the spy opens flat 10-96001 communique and " CopperSegregation-free Premixed Iron Powder for Powder metallurgy " (KawasakiSteel Technical Report 42 (May 2000) p.36-40) etc. and understands.But, described in above-mentioned Technical Report, think when utilizing the adhesive attachment copper powder much at one characteristic when showing with partially-alloyed adhering to.Just, do not know in the past partially-alloyedly to adhere to size distribution control with iron-based powder etc. and match, improved the fillibility at iron base powder mixture end, particularly real machine fillibility significantly by what make copper powder.
When it being adhered to the partially-alloyed surface of copper powder at atomized iron powder, be preferably as follows method, promptly preferred copper powder with average grain diameter 20～100 μ m is blended in the spray pattern iron powder, make after the mixed powder, make the copper in the copper powder partly be diffused in the iron powder surface by heat treatment, and make copper powder attached to spray pattern iron powder surface.After making that copper powder is partially-alloyed and adhering to, usually can carry out final heat of reduction and handle, still, the Cu that suppresses to be diffused in the iron particles from this moment measures, and the constrictive viewpoint of further improving the iron base powder mixture end is set out, and the average grain diameter of the copper powder that preferably adheres to is more than the 20 μ m.On the other hand, consider partially-alloyed the adhering to fully of copper powder carried out, and further improve the real machine fillibility at iron base powder mixture end, the average grain diameter of preferred copper powder is below the 100 μ m.
The particle diameter that the average grain diameter of copper powder adopts the size distribution that obtains with sieve classification when being the accumulative total rate 50% of basis weight benchmark.
Copper powder can use pure copper powder (electrolytic copper powder, atomized copper powder, redox copper powder, with the copper powder after these pulverizing or the granulation etc.), allows to sneak into the following element of 1 quality %.In addition, preferred copper powder mixes, partially-alloyed adhering to, and calculates with the copper amount of the total amount at relative iron base powder mixture end, and the content that makes copper is 0.5～30 quality %.Consider that from the alloying effect (reinforcement of sintered metal product etc.) of expection preferably setting the copper amount is more than the 1 quality %.On the other hand, from making the cost consideration at iron base powder mixture end, the preferably copper amount is set at below the 30 quality %.
Partially-alloyed adhesion heat as copper powder is handled, also can use aforesaid spy to open the heat-treating methods that carries out twice of records such as clear 53-92306 communique, but the method for being preferably as follows, promptly in reducing atmosphere, preferably in containing the gas atmosphere of hydrogen, set programming rate: 20～150 ℃/min, heat treatment temperature: heat-treat for 820～1000 ℃.Utilize this method can make that copper powder is partially-alloyed to be adhered to by a heat treatment, also favourable economically.
In addition, whether copper powder is fully attached to utilizing the copper degree of adhering to as giving a definition to estimate on the iron-based powder.Copper degree of adhering to is the ratio by the copper content in the integral body of the relative iron base powder mixture of the copper content in this iron base powder mixture end of 325 orders (45 μ m) end, just (by the copper content in this iron base powder mixture end behind 325 orders (45 μ m))/(the copper content in the integral body of iron base powder mixture end).Just, the aggegation particle diameter of copper powder is 5～28 μ m relatively, and is less by 325 purpose iron-based powder population ratios, thereby free state (not attached to the iron-based powder surface) copper powder is many more, and the value of aforementioned copper degree of adhering to is big more.In addition, need only iron powder all equably relatively attached to iron-based powder (it doesn't matter with the iron-based powder particle diameter), then aforementioned copper degree of adhering to is 1.The present inventor confirmed the result of research such as powder so long as aforementioned copper degree of adhering to be 2 following segregations in fact just no problem.
Below, consider from the compressibility at iron base powder mixture end and the viewpoint of fillibility, the total amount at relative iron base powder mixture end, the iron-based powder that uses among the present invention is set at has following size distribution:
Particle diameter is (also can be zero %) below the 18.5 quality % less than the particle of 45 μ m
The above particle less than 150 μ m of particle diameter 75 μ m is more than the 46 quality %
The above particle less than 180 μ m of particle diameter 150 μ m is less than 10 quality % (also can be zero %)
The above particle of particle diameter 180 μ m is 0.5 quality % following (also can be zero %).
In addition, consider fillibility, preferably setting the above particle of particle diameter 180 μ m is below the 0.1 quality %, and more preferably making maximum particle diameter is less than 180 μ m.In addition, consider further to improve fillibility, preferably setting the above particle less than 150 μ m of particle diameter 75 μ m is more than the 48 quality %, more preferably more than the 50 quality %.In addition, considering further to improve fillibility, is less than 15.0 quality % with particle diameter less than the particle of 45 μ m, more preferably is set at less than 12.7 quality %.
When the size distribution at the iron base powder mixture end is at least following any situation, the fillibility deterioration at iron base powder mixture end, that is, particle diameter surpasses 18.5 quality %, is that particle 10 quality %s more than, particle diameter 180 μ ms more than surpass 0.5 quality % below less than 46 quality %, more than the particle diameter 150 μ m less than the particle of 180 μ m less than the particle of 150 μ m more than the particle diameter 75 μ m less than the particle of 45 μ m.In addition, because surplus, promptly the above particle less than 75 μ m of 45 μ m compressibility, fillibility are not had big influence, so the present invention does not limit their content especially.
In addition, the size distribution of iron-based powder is used the value of being measured by the sieve distribution of Japanese powder metallurgy industry meeting specification JPMA P02-1992 regulation.
The iron-based powder that uses in making mixed powder of the present invention is 2.85Mg/m by making the preferred apparent density of iron powder except having above-mentioned size distribution
3More than, more preferably 2.90Mg/m
3More than, further improve the fillibility at iron base powder mixture end.In addition, apparent density can be measured by specification JPMA p06-1992 according to Japanese powder metallurgy industry.
The iron-based powder that uses preferably with commercially available atomizing straight iron powder, maybe will be implemented the partially-alloyed heat treated atomized iron powder of copper powder and pulverize the iron powder that obtains, and fit in above-mentioned size distribution after the screen sizing.
Impurity in the iron-based powder integral body, atomized iron powder that can be partially-alloyed with copper powder (behind the final annealing) has identical scope.
Powdered graphite, adhesive, free lubricant and the machinability improvement powder of alloying element powder also contained in iron base powder mixture of the present invention end except that containing iron-based powder.Iron-based powder and powdered graphite and machinability are improved the total amount with powder relatively, and powdered graphite, machinability are improved with below the preferred 3 quality % of powder difference, below the 5 quality %.In addition, the machinability of iron-based powder, powdered graphite or interpolation is again improved total amount 100 weight portions with powder relatively, and adhesive, free lubricant be preferred 0.1～1.0 weight portion, 0.1～0.5 weight portion respectively.For this reason, the copper content in the iron-based powder that in the manufacturing at iron base powder mixture of the present invention end, uses, than the content in the final iron base powder mixture end cooperate greatly about 10 quality %.In addition, the size distribution of the iron-based powder that uses during the manufacturing at iron base powder mixture of the present invention end is substantially the size distribution at iron base powder mixture end, but, the content at the relative iron base powder mixture of iron-based powder end is 95 quality % when above, and the size distribution of iron-based powder is consistent with the size distribution at iron base powder mixture end.
In addition, powder is used in the machinability improvement for powdered graphite or interpolation again among the present invention, uses the aforementioned adhesion agent to be fixed on the lip-deep processing of iron-based powder (being called segregation prevents to handle).Thus, reduce the powdered graphite, the machinability improvement powder that exist with free state, improve the fillibility at iron base powder mixture end.In addition, consider to make it have good fillibility, the degree of adhering to (carbon degree of adhering to) of preferred powdered graphite is more than 85%.
The degree of adhering to of the powdered graphite described in the present invention, the fixation degree of expression powdered graphite, specifically be that relative grain size is the ratio of the whole C assay value in the C assay value at iron base powder mixture end (by 100 μ m orders, and by 200 purpose iron base powder mixture ends) of 75 μ m (200 order)～150 μ m (100 order) and iron base powder mixture end.Just, carbon degree of adhering to=(the C assay values at 200 orders～100 purpose iron base powder mixture ends)/(the C assay value at total iron base powder mixture end).In this case because the powdered graphite of free state comes off from 200 orders～100 purpose iron base powder mixture ends, so powdered graphite equably attached on the iron-based powder time, aforementioned carbon degree of adhering to is 100%, the graphite of free state is many more, carbon degree of adhering to value is more little.
As the powdered graphite that alloy contains in the iron base powder mixture end with powder, the machinability of iron-based powder, powdered graphite or interpolation is again improved the total amount with powder relatively, below the preferred 3 quality %.In addition, consider alloying effect (improving the intensity or the hardenability of sintered body), preferably add more than the 0.3 quality %.
The machinability improvement powder that in the iron base powder mixture end, mixes the machinability of improving sintered body as required.As machinability improvement powder, consider the characteristic that sintered body requires, selected talcum powder; Metal sulfide powder such as MnS; CaF
2In the metal fluoride powder; Phosphoric acid Ca compound powders such as so-called hydroxyapatite or phosphoric acid hydrogen 1 hydrogen calcium, calcium pyrophosphate etc.Iron-based powder, powdered graphite and machinability are improved the total amount with powder relatively, and the machinability improvement preferably mixes below the 5 quality % with powder.
Be used for powdered graphite and machinability are improved the adhesive that is fixed on the iron-based powder surface with powder, be preferably as follows two kinds:
(1) be selected from following one or more,
Stearic acid,
Oleamide,
Stearic amide
The molten mixture of stearic amide and ethylene bis stearic acid amide
Ethylene bis stearic acid amide
Or
(2) be selected from the molten mixture of one or more and zinc stearate in following
Oleic acid,
Bobbin oil
Turbine oil.
In the present invention, the content of adhesive, iron-based powder and powdered graphite and machinability are improved total amount 100 weight portions with powder, preferred 0.1～1.0 weight portion relatively.Just, the segregation of considering further to improve graphite powder etc. prevents effect, preferably adds more than 0.1 weight portion.On the other hand, consider further to improve the fillibility at iron base powder mixture end, preferably add below 1.0 weight portions.
In the iron base powder mixture end, hybrid lubricant, be used for improving the iron base powder mixture end flowability, improve fillibility, when in metal mold, making the iron base powder mixture end carry out extrusion forming simultaneously at metal mold, because of frictional heat makes its fusion or softening, the withdrawal force of formed body is reduced.In order to make the above-mentioned effect of lubricant performance, lubricant is existed with free lubricant.Free lubricant of the present invention is in the iron base powder mixture end, and is not bonding with iron-based powder, powdered graphite etc., the free existence.
The content of free lubricant, iron-based powder, powdered graphite, machinability are improved total amount 100 weight portions with powder, preferred 0.1～0.5 weight portion relatively.Just, consider further to improve the fillibility at iron base powder mixture end, the content that preferably sets free lubricant is more than 0.1 weight portion.On the other hand, consider further to improve the fillibility and the compact density at iron base powder mixture end, the content that preferably sets free lubricant is below 0.5 weight portion.By making free lubricant amount, the apparent density at iron base powder mixture end can be increased to 3.1Mg/m in above-mentioned scope
3
Free lubricant is preferably as follows two kinds:
(1) be selected from following one or more,
Thermoplastic resin cosmetics,
Zinc stearate,
Lithium stearate
Perhaps
(2) in one or more that in thermoplastic resin cosmetics, zinc stearate, lithium stearate, select, added one or more the material in following again
Stearic acid,
Oleamide,
Stearic amide,
The molten mixture of stearic amide and ethylene bis stearic acid amide
Ethylene bis stearic acid amide
The polyethylene of molecular weight below 10,000
Ethylene bis stearic acid amide and the molecular weight poly molten mixture below 10,000.
In addition, the content of one or more that from thermoplastic resin cosmetics, zinc stearate, lithium stearate, select, consider further to improve the flowability at iron base powder mixture end, the fillibility in metal mold, preferred iron-based powder relatively, powdered graphite, machinability improvement total amount 100 weight portions of powder are more than 0.05 weight portion.
In addition, thermoplastic resin cosmetics relatively hot plastic resin powder total amount preferably contains at least a in 50 quality the % above acrylate that is selected from monomer, methacrylate and the aromatic ethylene compound, makes its polymerization.This is to consider further to improve the flowability at iron base powder mixture end and preferred.In addition, monomer can use a kind of in acrylate, methacrylate and the aromatic ethylene compound separately, or mixes two or morely, can use any one.
As acrylate, for example have: methyl acrylate, ethyl acrylate, acrylic acid n-propyl, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, the own ester of acrylic acid uncle, cyclohexyl acrylate, acrylic acid-2-ethyl ester, acrylic acid n-octyl etc.
As methacrylate, for example have: the just own ester of methyl methacrylate, EMA, n propyl methacrylate, isopropyl methacrylate, n-BMA, isobutyl methacrylate, methacrylic acid, cyclohexyl methacrylate, methacrylic acid-2-ethyl ester, n octyl methacrylate etc.In addition, wherein be particularly suitable for using methyl methacrylate.
As aromatic ethylene compound, for example have: styrene, AMS, divinylbenzene and the monomer of substituent methyl, ethyl, propyl group, butyl etc., for example vinyltoluene, isobutyl-benzene ethene etc. on the phenyl ring of these monomers.
In at least a monomer in three kinds of above-mentioned monomers, above-mentioned relatively three kinds of monomer total amounts add less than 50 quality % can copolymerization other monomer, make thermoplastic resin cosmetics, it can be used as free lubricant.
Above-mentioned can with the monomer of three kinds of monomer copolymerizations, for example have:
Unsaturated monocarboxylics such as acrylic acid, methacrylic acid, acrylic acid-2-ethyl ester, butenoic acid, cinnamic acid;
Unsaturated dicarboxylic or its acid anhydrides such as maleic acid, itaconic acid, fumaric acid, citraconic acid, chloromaleic acid;
The monoesters and the derivative thereof of unsaturated dicarboxylics such as monomethyl maleate, butyl maleate, monomethyl fumarate, monomethyl ester, monomethyl itaconate, itaconic acid mono ethyl ester, itaconic acid mono;
Ethylene oxidic ester classes such as GMA, glycidyl acrylate, right-the vinyl benzoic acid ethylene oxidic ester, itaconic acid methyl ethylene oxidic ester, maleic acid ethyl ethylene oxidic ester, vinyl sulfonic acid ethylene oxidic ester,
Butadiene monoxide, VCH monoxide, 5,6-epoxy hexene, 2-methyl-5, epoxy olefines such as 6-epoxy hexene;
Vinyl cyanide such as acrylonitrile, methacrylonitrile;
Vinyl esters such as vinyl acetate, propionate, tetradecanoic acid vinyl acetate, oleic acid vinyl acetate, benzoic acid vinyl acetate;
Butadiene, different propylene, 1,3-pentadiene, cyclopentadiene equiconjugate diene compound;
1, non-conjugated diene based compounds such as 4-hexadiene, bicyclopentadiene, ethylidene norcamphane.
In addition, as monomer that can copolymerization, three kinds of monomer total amounts that can be above-mentioned are relatively added the cross-linkable monomer with reactive plural pair of key that equates in fact of 0.1～2 quality %.
As cross-linkable monomer, can use glycol diacrylate, ethylene glycol dimethacrylate, butanediol diacrylate, butanediol dimethylacrylate, trimethylolpropane acrylates, the trimethylolpropane dimethylacrylate, trimethylolpropane triacrylate, trimethylol-propane trimethacrylate, hexanediyl ester, hexanediol dimethacrylate, low polyoxyethylene diacrylate, low polyoxy ethene dimethylacrylate, and the aromatic diethylene base monomer of divinylbenzene etc., trihemellitic acid three propylene esters, three anil isocyanates etc.
And preferred its average grain diameter of described thermoplastic resin cosmetics is that 0.03～5 μ m, aggegation average grain diameter are 5～50 μ m, and the mean molecule quantity that utilizes solution specific viscosity method to measure is 30,000～5,000,000.
An average grain diameter described in the present invention is meant as shown in Figure 2, the mean value of the particle diameter 3 of each particle of thermoplastic resin cosmetics (primary particle 1).In addition, described aggegation average grain diameter is meant the mean value of the particle diameter 4 of the agglutination particle 2 that primary particle 1 aggegation forms.An average grain diameter is to utilize the sem observation agglutination particle, measures the diameter (primary particle size) of primary particle more than 50 that forms agglutination particle, the mean value of being got from the photo of picked-up.In addition, the aggegation average grain diameter is equally from the photo of sem observation agglutination particle picked-up, and about 50 of agglutination particles are measured particle diameter, the mean value of being got.
In addition, mean molecule quantity utilizes solution specific viscosity method to measure among the present invention.So-called solution specific viscosity method is meant, sample resin 0.2g is dissolved among the oxolane 50ml, ratio with the viscosity B of the viscosity A of gained solution under 35 ℃ and the solvent of uniform temp (oxolane), try to achieve A/B (specific viscosity), from try to achieve the mean molecule quantity of sample resin by the relation of predetermined specific viscosity one mean molecule quantity of the various normal polyethylenes of known flat average molecular weight.
Preferred 0.03～5 μ m of an average grain diameter of thermoplastic resin cosmetics.That is, consider the manufacturing cost at iron base powder mixture end, a preferred average grain diameter is more than the 0.03 μ m.In addition, consider further to improve formed body density, a preferred average grain diameter is below the 5 μ m.In addition, more preferably an average grain diameter is 0.03～3 μ m.
Preferred 5～50 μ m of the aggegation average grain diameter of thermoplastic resin cosmetics.Just consider further to improve the flowability and the hopper discharge property at iron base powder mixture end, preferred aggegation average grain diameter is more than the 5 μ m.On the other hand, consider further to improve the hot strength of sintered body, preferred aggegation average grain diameter is below the 50 μ m.In addition, aggegation average grain diameter more preferably is set at 10～40 μ m.
In addition, thermoplastic resin cosmetics can mix the different two or more thermoplastic resin cosmetics of average grain diameter one time, in this case, preferably adjust blending ratio, so that the mean value (using the load average of each powder quality) of the particle diameter of each powder that mixes is 0.03～5 μ m.
And the mean molecule quantity that utilizes solution specific viscosity method mensuration of thermoplastic resin cosmetics is preferably in 30,000～5,000,000 scope.Just, consider the manufacturing cost at iron base powder mixture end, preferred mean molecule quantity is more than 30,000.On the other hand, consider further to improve the flowability and the hopper discharge property at iron base powder mixture end, preferred aggegation average grain diameter is below 5,000,000.
Manufacture method to above-mentioned thermoplastic resin cosmetics among the present invention is not particularly limited, and the method for using in the manufacturing of fine toners such as polymethyl methacrylate all was fit to use in the past.In these methods, do not form imperceptible particle diameter, and can obtain yet suitable application of polymerization of spherical particle, for example, fine suspension polymerization, emulsion polymerization method, sowing emulsion polymerization method etc.
Fine suspension polymerization preferably uses oil-soluble initiator as radical polymerization initiator, before polymerization begins, the particle diameter of monomer oil droplet is homogenized handle and regulate in advance, makes it carry out even dispersin polymerization.
The oil-soluble radical polymerization initiator, for example can use:
Benzoyl peroxide, peroxidating two-3,5, peroxidating two acyl classes such as 5-trimethyl acetyl, dilauroyl peroxide;
Peroxy dicarbonates such as diisopropyl peroxydicarbonate, two-sec-butyl peroxy dicarbonate, two-2-ethylhexyl peroxy dicarbonate;
Peroxyesters such as t-butylperoxy pivarate, tert-butyl hydroperoxide neodecanoic acid ester;
Organic peroxides such as acetyl cyclohexyl sulphonyl peroxide, succinyl peroxide;
2,2 '-azobis isobutyronitrile, 2,2 '-azo is two-2-methylbutyronitrile, 2, azo-compounds such as the two methyl pentane nitriles of 2 '-azo etc.
These radical polymerization initiators can be used alone in addition, also can mix two or more uses.Its use amount can suitably be selected according to kind and the amount and the adding mode etc. of monomer, usually, uses per 100 weight portions of monomer, preferably uses initator in 0.001～5.0 weight portion scope.
In addition, when implementing fine suspension polymerization, use surfactant and dispersant usually.As surfactant, for example have:
The alkyl sulfate salt of lauryl sulfate ester sodium, myristyl sodium sulfovinate etc.;
Alkylaryl sulfonates such as neopelex, Potassium dodecylbenzenesulfonate class;
Dioctyl sulfo group amber is moored sour sodium, dihexyl sulfo group amber is moored sulfo group amber pool Barbiturates such as sour sodium;
Fatty acid salt such as ammonium laurate, potassium stearate;
Polyxyethylated sulfuric ester salt;
Polyxyethylated aromatic yl acid ester salt;
Anionic surfactant classes such as dodecyl diphenyl ether sodium disulfonate;
Spans such as sorbitol monooleate, polyoxyethylene sorbitol monostearate;
Nonionic surface active agent classes such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether class;
Cationic surface active agents such as cetylpyridinium chloride, bromination cetyl alkane ammonium methyl etc.
In addition, as dispersant, for example have: polyvinyl alcohol, methylcellulose, polyvinylpyrrolidone etc.
These surfactants and dispersant can be used alone, and it is two or more also can to mix use.Common every use monomer 100 weight portions, its use amount is 0.05～5 weight portion, the value in preferred 0.2～4 weight portion scope.
In addition, in this fine suspension polymerization, at first in aqueous medium, add oil-soluble initiator, monomer, surfactant and reagent and additive in polymerization and other additives such as higher fatty acids class of using as required or higher alcohols in advance, mix, utilize the homogenizer processing that homogenizes, adjust the particle diameter of oil droplet.Homogenizer for example can use colloid mill, oscillating mixer, two-part high-pressure pump, utilizes high-pressure injection that nozzle and spout etc. carry out, ultrasonic wave stirring etc.And, the adjusting of oil droplet size, the amount of form, surfactant and the additive of the shearing force control when not homogenized processing, the stirring condition in the polymerization, reaction unit etc. influences, and these can select suitable condition according to simple preliminary experiment.And, the treatment fluid that homogenizes of all monomers is delivered to polymeric kettle, warming while stirring is at leisure carried out polymerization under the temperature in 30～80 ℃ of scopes usually.
Processing can obtain emulsion or suspension like this, and the particle that average grain diameter is the thermoplastic resin powder of 0.03～5.0m disperses wherein equably.Make this emulsion or spray dried, perhaps make the thermoplastic resin particles aggregate after, isolated by filtration slurries, drying, pulverizing can obtain the thermoplastic resin powder.The weight average molecular weight of its thermoplastic resin can utilize reaction temperature or degree of polymerization conditioning agent to be adjusted to the value of hope.
Below, an example in the preferred manufacture method in iron base powder mixture of the present invention end is described.
At first, prepare iron-based powder, wherein, this powder is by the atomizing straight iron powder with at atomizing straight iron powder upper surface branch alloying copper powder and its atomized iron powder that adheres to is constituted, and has above-mentioned size distribution.In this iron-based powder, cooperate powdered graphite or and then cooperate and improve cutting with powder and adhesive, and mix, do resulting mixture.In addition, the relative iron-based powder of adhesive, powdered graphite and machinability are improved total amount 100 weight portions with powder, cooperate 0.1～1.0 weight portion.
As adhesive, be preferably selected from the molten mixture of stearic acid, oleamide, stearic amide, stearic amide and ethylene bis stearic acid amide and in the ethylene bis stearic acid amide one or more.
This mixture is heated while stirring, mixes, form once mixture.The heating-up temperature of once mixture is preferably set to
When adhesive is a kind, than high 10～100 ℃ temperature of its fusing point;
Adhesive is more than 2 kinds the time, more than the fusing point of the adhesive that fusing point is minimum+10 ℃, and the temperature below the fusing point of the highest adhesive of fusing point.
By heating, make at least a adhesive fusion.
When being lower than above-mentioned lower limit temperature, adhesive can not be brought into play its bonding function, and in addition, when surpassing above-mentioned ceiling temperature, because thermal decomposition etc. descend bonding function, the hopper discharging performance reduces simultaneously.
Then, cool off this once mixture, make adhesive, make thus powdered graphite or and then machinability improve with powder securely on the surface attached to iron-based powder.
Powdered graphite or and then machinability improve and to be fixed in the lip-deep once mixture of iron-based powder with powder, add lubricant again, mix (secondary mixing), preferably make the iron base powder mixture end.The addition of lubricant, iron-based powder, powdered graphite and machinability are improved total amount 100 weight portions with powder, preferred 0.1～0.5 weight portion relatively.
The temperature that secondary mixes preferably sets the fusing point less than the minimum lubricant of the fusing point in the lubricant that adds.In addition, more preferably room temperature.The lubricant that adds in secondary mixes forms free lubricant, does not combine with iron-based powder etc., is present in the mixed powder with free state.
The lubricant that in secondary mixes, adds, preferred necessarily containing is selected from above-mentioned thermoplastic resin cosmetics, zinc stearate, the lithium stearate one or more, and, contain in the molten mixture that is selected from stearic acid, oleamide, stearic amide, stearic amide and ethylene bis stearic acid amide, ethylene bis stearic acid amide, polyethylene, ethylene bis stearic acid amide and the molecular weight poly molten mixture below 10,000 of molecular weight below 10,000 one or more as required.
In addition, iron base powder mixture of the present invention end also can utilize the operation manufacturing of following (1)～(4).
(1) in iron-based powder, add powdered graphite or and then add machinability and improve and use powder, aqueous adhesive spraying back is mixed, make once mixture, wherein, iron-based powder is by the atomizing straight iron powder and makes copper powder partially-alloyed and atomized iron powder that adhere to constitutes from the teeth outwards, and has above-mentioned size distribution.Aqueous adhesive preferably uses in oleic acid, bobbin oil, the turbine oil one or more.
(2) in this once mixture, add zinc stearate, be mixed and made into secondary mixture.The addition of zinc stearate, with one or more the calculation of total in oleic acid, bobbin oil, the turbine oil, iron-based powder, powdered graphite and machinability are improved total amount 100 weight portions with powder relatively, are 0.1～1.0 weight portion.
(3) this secondary mixture limit being heated to 110～150 ℃ of limits mixes.By heating, make more than one fusions in zinc stearate and oleic acid, bobbin oil, the turbine oil at least.Then by this secondary mixture of cooling, make powdered graphite or and then machinability improve with powder securely on the surface attached to iron-based powder.
(4) powdered graphite or and then machinability improve and to be fixed in the lip-deep secondary mixture of iron-based powder with powder, add lubricant again, carry out three times and mix, make the iron base powder mixture end.The temperature of mixing for three times is preferably less than the minimum in the fusing point of the lubricant that adds.In addition, more preferably room temperature.In addition, the relative iron-based powder of the addition of lubricant, powdered graphite and machinability are improved total amount 100 weight portions with powder, preferred 0.1～0.5 weight portion.The lubricant that when three times are mixed, adds, not bonding with iron-based powder etc., exist with free state, form free lubricant.
The lubricant that in three times are mixed, adds, preferred necessarily contain in above-mentioned thermoplastic resin cosmetics, zinc stearate, the lithium stearate one or more, and, contain in the molten mixture that is selected from stearic acid, oleamide, stearic amide, stearic amide and ethylene bis stearic acid amide, ethylene bis stearic acid amide, polyethylene, ethylene bis stearic acid amide and the molecular weight poly molten mixture below 10,000 of molecular weight below 10,000 one or more as required.
In addition, iron base powder mixture of the present invention end is not limited to above-mentioned manufacture method.
For example, also can make in the organic solvent dissolving or the adhesive that disperses, iron-based powder, alloy powder or and then the machinability of adding improve with after the powder, the evaporation organic solvent, fixed alloy powder, machinability improvement powder on the iron-based powder surface, afterwards, add free mix lubricant, make the iron base powder mixture end.
Iron base powder mixture of the present invention end is fit to use the processing method in the general powder metallurgy, can be used for the manufacturing machine parts.Concrete, iron base powder mixture of the present invention end is filled in the metal mold, after the compression forming, carry out shaping as required, sintering is made sintered body.Carry out heat treatments such as carburizing and quenching, bright quenching, high-frequency quenching behind the sintering again, make goods (mechanical part etc.).
Embodiment
Embodiment 1
In the No.1 shown in the table 1～No.4 water atomization state iron powder, the iron powder of (a)～(g) that kind, the particle diameter shown in the table 1 of the combined amount shown in the interpolation table 1 is different mixes, and makes mixed-powder.Then in this mixed powder, make the partially-alloyed heat treatment of adhering to of copper powder, pulverize then and classification, then, make atomized iron powder (the partially-alloyed atomized iron powder that adheres to of copper) No.1～No.7, it has the size distribution shown in the table 2, apparent density, and copper powder is partially-alloyed attached to the surface.In addition, size distribution adopts the screening distribution of Japanese powder metallurgy industry meeting specification JPMA P02-1992 regulation.Apparent density can be measured by specification JPMA P06-1992 according to Japanese powder metallurgy industry.
It is with the above-mentioned mixed powder H that packs into that partially-alloyed adhesion heat is handled
2In the heat-treatment furnace of atmosphere, heat up with the programming rate of 50 ℃/min, under the condition of 20 ℃ of dew points 880 ℃ of heat treatments that keep 1 hour.Here double as finally reduces processing.
Table 1
*) with respect to the ratio of atomizing straight iron powder total amount
Table 2
Then, at commercially available atomizing straight iron powder (iron powder No.a, No.b) or be adjusted in the atomizing straight iron powder (iron powder No.c) of the size distribution shown in the table 3 with size distribution shown in the table 3, with (the atomized iron powder No.1～No.7) of the partially-alloyed atomized iron powder that adheres to of copper shown in proportioning shown in the table 4 and the combined amount interpolation table 2, mix, make iron-based powder with the size distribution shown in the table 4, apparent density (iron-based powder No.A～No.R).In addition, iron powder No.a is that Jfe Steel Corp system KIP301A (trade mark), iron powder No.b are the system KIP260A (trade mark) of Jfe Steel Corp.
In addition, iron-based powder No.F～No.M prescreening and make the size distribution shown in the atomizing straight iron powder formation table 4, the partially-alloyed atomized iron powder that adheres to of copper shown in the table 2 of the combined amount shown in the interpolation table 4 mixes with V-Mixer afterwards, makes iron-based powder.
Iron-based powder No.N only is the iron-based powder of the partially-alloyed atomizing straight iron powder that adheres to atomized iron powder of cupric (atomizing straight iron powder No.a) not.
Table 3
Table 4
Label "-" is not add in the table.
In iron-based powder 990g shown in the table 4 and powdered graphite (average grain diameter 23 μ m) 10g, a kind of as in the oleic acid of the use level shown in the part of the adhesive spraying table 7, turbine oil, the bobbin oil mixes afterwards, carries out mixed once.
In addition, in iron base powder mixture end No.16 (conventional example), use iron-based powder No.N (having only the atomizing straight iron powder) as iron-based powder, wherein this iron-based powder No.N does not use copper powder partially-alloyed attached to lip-deep iron-based powder, adds powdered graphite in iron-based powder, reaches copper powder (electrolytic copper powder: average grain diameter 23 μ m).In addition, in the No.23 and 24 of iron base powder mixture end, add machinability improvement powder in the time of the addition of change powdered graphite.Under the various situations, the content of each powder all is according to the value shown in the table 7, and in addition, the total amount that iron-based powder, alloy improve with powder with powder and machinability is 1000g.
Then, in the once mixed mixed powder, as the other part of adhesive, add the zinc stearate of the amount of Table 7, packing into adds in the Hot mixer, mixes fully, does resulting mixture.Then, this mixture is heated to the secondary shown in the table 7 mixes heating-up temperature, stir simultaneously, make secondary mixture.
Then, limit stirring secondary mixture limit is cooled to them below 85 ℃.Be cooled to again after 40 ℃, add form the lubricant of kind, amount shown in the table 7 of free lubricant, carry out three times and mix, make its evenly after, discharge from adding Hot mixer, make the iron base powder mixture end.In addition, the label of the thermoplastic resin cosmetics that adds when mixing for three times and the relation of kind are shown in table 5 with composition, polymerization, average grain diameter, aggegation average grain diameter and a mean molecule quantity.In addition, the label of the free lubricant beyond thermoplastic resin cosmetics, zinc stearate, the lithium stearate and the relation of kind are shown in table 6.
To the iron base powder mixture end that obtains, try to achieve the degree of adhering to of powdered graphite, degree of adhering to, apparent density, fillibility and the density as pressed (compressibility) of copper powder.Assay method is as follows.
(1) degree of adhering to of powdered graphite (carbon degree of adhering to)
As the yardstick of the segregation degree of the powdered graphite that contains in the expression iron base powder mixture end, measure the degree of adhering to of powdered graphite according to following steps.
With iron base powder mixture end screening, to by 100 orders (perforate: sieve 150 μ m), not have 200 orders of passing through (perforate: Shai powder 75 μ m), carry out the quantitative analysis of carbon.In addition, the whole carbon in iron base powder mixture end before the quantitative analysis screening.From the result who obtains, utilize the degree of adhering to of the powdered graphite of following definitions, estimate segregation.It is big more that it is defined as this value, and the segregation of powdered graphite in the iron base powder mixture end is more little.
The degree of adhering to of powdered graphite (%)={ (by 100 orders, the C assay value at the iron base powder mixture end of the granularity by 200 order scopes)/(the whole C assay value in iron base powder mixture end) } * 100
(2) degree of adhering to of copper powder (copper degree of adhering to)
With iron base powder mixture end screening, to by 325 orders (perforate: Shai powder 45 μ m), carry out the copper quantitative analysis.In addition, the whole copper in iron base powder mixture end before the quantitative analysis screening.Degree of adhering to from the copper powder of the evaluation of result following definitions that obtains.It is defined as this value more near 1, and copper powder is firm more to adhering to of iron-based powder.
The degree of adhering to of copper powder=(the copper assay value at the iron base powder mixture end by 325 purpose granularities)/(the whole copper assay value in iron base powder mixture end)
(3) apparent density
The apparent density of iron-based powder mixed powder can be measured by specification JPMAP06-1992 according to Japanese powder metallurgy industry.
(4) fillibility
Use the device that schematically shows its configuration among Fig. 1, according to the fillibility at following step measurements iron base powder mixture end.
(size: 100 * 60 * 20mm) speed with 200mm/s move to the metal mold direction to make the powder case 5 that is filled with iron base powder mixture end 150g, it is stopped directly over the metal mold 6 with metal blowhole of t=0.5mm (length 60 * degree of depth 60mm), keep 1s, retreat with the speed of 200mm/s after being filled in the iron base powder mixture end in the metal mold.After the filling,, make formed body with the pressure forming of 480Mpa.In addition, make 10 formed bodys with identical iron base powder mixture end.
The quality of the formed body that mensuration obtains is tried to achieve packed density (=(formed body quality)/(volume of metal blowhole).To be worth as filling except that the value that this packed density obtains with the apparent density at iron base powder mixture end, estimate fillibility.In addition, filling value is the average of 10 formed bodys.The big more expression fillibility of filling value is good more.
In addition, to each iron base powder mixture end,, try to achieve ratio, (standard deviation of quality)/(the average formed body quality) of the average formed body quality of relative mass deviation from the mass deviation of the formed body (10) that obtains.This ratio is converted into relative value, estimates the formed body mass deviation at each iron base powder mixture end, wherein this relative value is benchmark (=1.00) with the value of conventional example (iron base powder mixture end No.16).
(5) density as pressed (compressibility)
Is the material ingot of diameter 25mm * height 20mm with the iron base powder mixture end with the 490MPa pressure forming, makes formed body.Measure the density (density as pressed) of these formed bodys, estimate compressibility.
The result who obtains is illustrated in the table 8.
Table 5
*) MMA: methyl methacrylate
BMA: n-BMA
EA: ethyl acrylate
BA: n-butyl acrylate
AN: acrylonitrile
BD: butadiene
ST: styrene
Table 6
| Label No. | The kind of free lubricant |
| a | Stearic acid |
| b | Oleamide |
| c | Stearic amide |
| d | The molten mixture of stearic amide and ethylene bis stearic acid amide |
| e | Ethylene bis stearic acid amide |
| f | The polyethylene of molecular weight below 10,000 and the molten mixture of ethylene bis stearic acid amide |
| g | Calcium stearate |
| h | The polyethylene of molecular weight below 10,000 |
Table 8
Its apparent density of any of example of the present invention all is 3.10Mg/m
3More than, and when the degree of adhering to of powdered graphite is 85% when above, segregation diminishes significantly, and when the filling value be 0.83 when above, fillibility is good, the mass deviation of formed body is also little than conventional example.In addition, with the particle diameter of the partially-alloyed copper powder that adheres to example of the present invention (iron base powder mixture end No.11), some reduction of its density as pressed (compressibility) less than proper range (more than the 20 μ m).
In addition, in the size distribution of iron-based powder and/or the apparent density comparative example outside scope of the present invention, the filling value is little, and fillibility is low, and the mass deviation of formed body is big.
As iron-based powder, do not use the conventional example (iron base powder mixture end No.16) that makes the partially-alloyed iron powder of copper powder from the teeth outwards, the filling value is little, and fillibility is low, and particularly the mass deviation of formed body is big.
The adhesive of kind shown in the iron-based powder 990g shown in the table 4, powdered graphite (average grain diameter 23 μ m) 10g, the table 9 and the amount of in adding Hot mixer, packing into, fully mix, and then when continue stirring, be heated to the mixed once heating-up temperature shown in the table 8, carry out mixed once.
Then, while stirring once mixture is cooled to below 85 ℃.Be cooled to again after 40 ℃, add form the lubricant of kind, amount shown in the table 9 of free lubricant, carry out secondary and mix, make its evenly after, discharge from adding Hot mixer, obtain the iron base powder mixture end.
In addition, in iron base powder mixture end No.2-16 (conventional example), as the iron base powder mixture end, use iron-based powder No.N (having only the atomizing straight iron powder), this iron-based powder No.N does not use the partially-alloyed atomized iron powder that adheres to of copper powder, in this iron-based powder No.N970g, add powdered graphite 10g, add again copper powder (electrolytic copper powder: 20g average grain diameter 23 μ m), carry out mixed once.In addition, in iron base powder mixture end No.2-18 and 2-19, in the addition that changes powdered graphite, add machinability improvement powder.At this moment, the content of each powder is according to the value shown in the table 9, and the total amount that iron-based powder, alloy improve with powder with powder and machinability is 1000g.
In addition, the relation of the label of the thermoplastic resin cosmetics of the fashionable interpolation of secondary mixing and kind is illustrated in the table 5 with composition, polymerization, primary particle size, aggegation particle diameter and mean molecule quantity.In addition, the label of the free lubricant beyond expression thermoplastic resin cosmetics, zinc stearate, the lithium stearate and the relation of kind in table 6.
To the iron base powder mixture end that obtains, with the embodiment 1 the same degree of adhering to of powdered graphite, degree of adhering to, apparent density, fillibility and the density as pressed (compressibility) of copper powder measured.In addition, the formed body mass deviation is that benchmark is estimated with relative value with the value of conventional example (iron base powder mixture end No.2-16).
The result who obtains is as shown in table 10.
Table 10
Its apparent density of any of present embodiment all is 3.10Mg/m
3More than, and when the degree of adhering to of powdered graphite is 85% when above, segregation diminishes significantly, and when the filling value be 0.85 when above, fillibility is good, the mass deviation of formed body is also little than conventional example.
In addition, the particle diameter of the partially-alloyed copper powder that adheres to exceeds in proper range (more than the 20 μ m) example of the present invention (iron base powder mixture end No.2-11), some reduction of its density as pressed (compressibility).
In addition, in the size distribution of iron-based powder and/or the apparent density comparative example outside scope of the present invention, the filling value is little, and fillibility is low, and the mass deviation of formed body becomes big.
Make the iron base powder mixture end No.1,16,19 and iron base powder mixture end No.2-1 and the 2-16 of embodiment 2 of 1 ton embodiment 1 respectively.By using the powder metallurgic method of each mixed-powder, the metal mold of the metal blowhole shape of representing with Fig. 3 A and Fig. 3 B is made 1000 spur gear (dimensional units: mm) continuously.The tooth portion of Fig. 3 A shows with the abridged form, is the tooth of benchmark pitch diameter (the benchmark pitch diameter of representing with the single-point line) 38mm, crown diameter 40mm, the number of teeth 38 (modulus=1).In addition, profile of tooth is made involute profile.
In gear shape, fill mixed powder, use the metal mold as the flat shape of metal blowhole portion, fill with the similar filling device of Fig. 1 with Fig. 3 A.After the powder case arrives directly over the metal blowhole with translational speed 250m/s, in case it is stopped, relatively the every front and back 5mm of direct of travel carry out 3 times repeatedly motion (oscillating movement) afterwards its speed with 250m/s is retreated.The translational speed of the powder case in the vibration is 250m/s.Compact density is 6.8Mg/m
3
The weight of the goods gear that mensuration obtains is measured the standard deviation of its weight.The standard deviation that relatively obtains as 1.00 relative value in order to test powder 2-16.The results are shown in the table 11.
In addition, use the device of Fig. 1, make itself and the value of the filling value of except that t=1mm, under the condition identical, measuring, remember in table 11 in the lump with embodiment 1.In metal blowhole 1mm, the difference of only controlling the conventional example of size distribution and example of the present invention is not obvious, but when the metal blowhole was set at 0.5mm, difference was obvious.And in the evaluation of real machine fillibility, mass deviation is more a lot of than will reducing of being envisioned from the width (1.6mm degree) of shape, particularly gear, and the present invention can obtain reducing 34～44% remarkable result.
In addition, the minimizing of moulding product quality deviation is relevant with the improvement of raw material yield rate and moulding productivity (the qualified products manufacture of unit interval), thereby becomes an important index of real machine fillibility.
Table 11
The invention effect
The present invention can obtain the iron base powder mixture end of good metal mold fillibility, the particularly powder used in metallurgy of good real machine fillibility. Its result, even in the metal mold with metal blowhole in a narrow margin, fill, also can the little formed body of workmanship deviation, have remarkable result producing.
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| UA95096C2 (en) * | 2005-12-30 | 2011-07-11 | Хеганес Аб | Iron-based powder metallurgical composition, composite lubricant on its base and method of production thereof |
| EP2513918B1 (en) * | 2009-09-18 | 2016-07-13 | Höganäs AB | Ferromagnetic powder composition and method for its production |
| BR112014020536B1 (en) * | 2012-02-24 | 2019-05-14 | Hoeganaes Corporation | METALURGIC POWDER COMPOSITION |
| JP5831440B2 (en) * | 2012-12-17 | 2015-12-09 | 株式会社ダイヤメット | Raw material powder for powder metallurgy |
| CN103231050B (en) * | 2013-03-30 | 2015-08-05 | 安徽省恒宇粉末冶金有限公司 | A kind of Powder metallurgy horizontal gear and preparation method thereof |
| CN103231052B (en) * | 2013-03-30 | 2015-08-05 | 安徽省恒宇粉末冶金有限公司 | A kind of powder metallurgy central gear and preparation method thereof |
| CN103233166B (en) * | 2013-03-30 | 2015-12-23 | 安徽省恒宇粉末冶金有限公司 | A kind of powder metallurgy toothed segment and preparation method thereof |
| CN103305743B (en) * | 2013-06-18 | 2015-04-15 | 北京科技大学 | Method for preparing pure iron and iron-phosphorus magnetically soft alloy product through powder metallurgy process |
| CN105377477B (en) * | 2013-07-18 | 2017-11-24 | 杰富意钢铁株式会社 | The manufacture method of powder used in metallurgy mixed powder and its manufacture method and iron-based powder sintered body |
| US20160223016A1 (en) * | 2013-10-03 | 2016-08-04 | Ntn Corporation | Sintered bearing and manufacturing process therefor |
| CN104096834A (en) * | 2014-07-18 | 2014-10-15 | 常熟市迅达粉末冶金有限公司 | Additive for powder metallurgy |
| CN104550925A (en) * | 2014-12-25 | 2015-04-29 | 佛山市盈峰粉末冶金科技有限公司 | Manganese-contained powder metallurgy material for preparing iron-based structural component and preparation method of manganese-contained powder metallurgy material |
| KR20180031749A (en) * | 2015-09-18 | 2018-03-28 | 제이에프이 스틸 가부시키가이샤 | Iron-based sintered compact and method for producing same |
| CN106222522A (en) * | 2016-08-31 | 2016-12-14 | 成都威士达粉末冶金有限公司 | A kind of powder metallurgical composition manufacturing motor housing, and the method manufacturing motor housing |
| CN108994309A (en) * | 2018-08-31 | 2018-12-14 | 鞍钢重型机械有限责任公司 | A kind of sinter-hardened water mist alloy powder and its manufacturing method |
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2005
- 2005-01-21 CN CNB2005100046858A patent/CN100558488C/en not_active Expired - Lifetime
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