DE1936029A1 - Heat-resistant, oxide-free alloys and processes for their manufacture - Google Patents

Description

DR. KURT-RUDOLF ElKENBERG

PATENT ADVOCATE

S HANNOVER · SCHACKBTR ASSE 1 · TELEPHONE (0911) 0140 90 ■ CABLE PATEHTION HANNOVER

HT Research Institute 205/21

Y / heat-resistant, oxide-free alloys and methods of making them

The invention relates to heat-resistant, oxide-free Alloys for use in cutting tools, forcing, Dies and corresponding parts at risk of wear, or for use as building alloys. The invention relates to continues to manufacture these alloys and their processing into fittings.

It is known that with excellent for Y. 'tools, Dies or the like. Usable alloys the best

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metallurgical. Characteristics are given when a A metallic matrix is also present in the case of elevated temperate doors which contains fine, hard carbon compounds in a uniform distribution. The matrix is preferred a solid solution of metals like 2. 3. Bisen. or cobalt, with one or more of the carbide-forming elements Chromium, vanadium, tungsten, molybdenum or dergi. In the Production of such alloys by conventional methods is divided into the carbide-forming elements, whereby a Rope these elements with that contained in the alloy Carbon with the formation of hard, wear-resistant complaints Carbides react while another rope remains in the matrix and acts as a solidification agent in the solid solution ν / becomes ineffective.

In these alloys, the carbides contribute significantly to the wear resistance, but they are ... "u: 3 extremely brittle and therefore reduce ductility ces- materials. If the carbide content is sufficient, the - material can no longer be deformed in an economical manner. Therefore it has been used so far in the manufacture of hard Alloys used for tools, dies and dergi. are useful and have very high carbide contents, necessary was to bring this directly into the required shape by casting and then just fine-grind it.

The casting processes that have been customary up to now for production However, such alloys have a natural disadvantage that is decisive for the properties of the solid material influenced. The fact is that the cooling rate of the liquid metal - at least a very large one Proportion --- ■: the size and distribution of the carbides in the solid ·

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Material controls. In the case of a block of faster steel weighing several tons, the cooling down "windiness" is so little that the carbides grow in enough time to grow into very coarse, continuous rushing within the material. Although these are iretse, if the 'block \\ e ± 2' forged and hot rolled, broken up into finer Karbidtcilcher., but even these are finer Karbi ^ oilchen still undesirably large and even if the "block hot worked and has been drawn to a diameter of 1 "or less. In addition, this unidirectional hot deformation also produces so-called" calidars ", which lead to anisotropic material strength and wear resistance.

Efforts have already been made towards -.v_if an increase in the cooling rate of the alloys made, iiüdem molding materials of high V-shape conductivity were used. The rate of growth of the Ivar'oido however, it is so large that even with small ones G-ußblocks undesirably large carbide structures occur. For example 1/4 "strong front pieces from one Tool alloy based on cobalt-chrome, even with very rapid cooling from the as-cast state still increases considerably large carbide particles at the level of the surface were larger than about 0.01 cm, and their size at the center of the workpiece still increased considerably. Another! Laughing part of all directly.-by casting formed work * · Part consists in that the carbide particles are oriented because of the directional solidification promoted by the thermal gradients in the casting will. These oriented carbides naturally feed anisotropic strength properties. Apart from this

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show all workpieces formed directly by casting the economic disadvantage of low production rates and poor yields »and in particular because of the necessary sprues, Steiger etc. /.

As a result, the conventional casting process thus plays a dominant role in that it determines the limit value up to which the carbide content of the alloys can still be tolerated. In the case of Söhneil turning steels and hot-work tool steels, the castings must contain less than about 20 percent by volume of carbide phase if they are still to be economically hot-formed into useful rod, rod or plate-shaped tools shaped tools are limited to a carbide content of about 30 volume percent, as larger Karbidgehalte a schwerwie- _r "constricting caused reduction of for use as a tool, die shape or the like necessary strength and toughness. ''. ^':. . _ ":""'.'" -

It is a well known fact that the performance of tools and dies and the like. Can be greatly improved if the carbide volume of the alloy is enlarged without at the same time the strength and toughness affect the alloy. It is also known that this result can be achieved by that the carbide particles are made exceptionally small and at the same time are distributed uniformly in the alloy. In this way, the 'large carbide particles are made by the caused "areas of weakness" are reduced.

BAD ORIGINAL -009 84 2/4 1-73- ~ - ~ 1 ~; _ «., ^ _

Accordingly, numerous efforts have already been made to reduce the carbide size reduce and the. Distribution of the carbides in the alloy ' to improve. For example, attempts have already been made Inoculating the castings, the mold while cooling to, - to oscillate or to vibrate, or that solidified To process the workpiece in different ways and to be treated warmly. None of these attempts have seen proven successful.

Finally, it is also known that a material suitable as a cutting tool, which is characterized by an extremely fine dispersion of hardening constituents in a solid, fine-grained metal matrix, can be produced from a non-ferrous glass pre-seal from pre-alloyed metal powder, the metal powder itself being produced under production conditions , -which result in a practically complete avoidance of coarse crystals in the powder. Because of the ultrafine dispersion of the carbides in the powder particles, alloys which cannot be hot-worked in the form of conventional castings can be compacted into dense rod-shaped or plate-shaped materials using conventional hot compression methods. This "" results in a considerable increase in strength and toughness "since the carbides" remained very fine and uniformly distributed in the end product. " are. The ultra-fine structures achieved with powder compaction technology also make it possible to increase the carbide volume within the alloy without impairing the machinability, strength or toughness of the material at the same time. This leads to a greater hardness and better wear resistance. ' : /. .; '..- ■

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. : ..- ■. _ ... ^ 009: 8J 2 "/ j; ill J ^:

193602a

However, it has now been found ... "that the

Pulv described erverdichtun ^r £ ;; jtechnik has a beträ.ol ".ulichen disadvantage. The z for the production of. j ^. ^ appropriate cutting tools, pre-alloyed powders can be most namely very difficult to completely seal a, rod or plate-shaped .Compress the material so that the individual powder particles have traces of an oxide film on them, which prevent the powder from being machinable

" A good bond between neighboring Puiverte, .lchen. Furthermore, they lead to a reduction in the strength and toughness of the hot-compacted memory material, the oxide inclusions _; inferences are very weak and crumbly. ■ - ■" - ■

:One has; already tried to oxidation of the powder during, to prevent the stage of hot sealing, ⁼ inden the powder in a container filled Werder ,, aiecer container then sealed (eg. 3 by SChv / hite) versciiloaserr is then the container is evacuated, and finally, after the hot processing, the container material is removed again .: However, apart from the cost and labor associated in particular with the evacuation, such a procedure does not bring any significant advantages, since it only results in further oxidation of the powder during the hot processing stage is prevented, but the problems are not overcome which "result from the" formation of harmful oxides during the powder production itself ". It is true that one can also try to overcome these last-mentioned problems by atomizing a melt using inert gas, cooling and also for powder production collects (while in conventional powder production processes there is water is often used). Bad luck-

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Licherweise, however, leads to the use of an inert gas in the case of the atomization process only to a partial solution of the oxidation on sprolal ems, while on the other hand the costs in powder production will increase significantly. Beyond that Inert gases also have the stream part that -the cooling rate of the atomized particles is noticeably reduced, so that the microstructures of the powder particles deteriorate accordingly.

Another process already used to reduce the oxygen content of atomized powders was, consists in the addition of carbonaceous Connections such as B. Soot to the powder. The soot will be there intimately mixed with the powder, the mixture 'is in it a thick-walled metal container is filled and the container is evacuated after it has been closed. The container is then heated to high temperatures (in the case of powders of the high-speed steel alloy K 2 to about 1200 ° C), and then it is heated with its contents by z. B. Presses hot worked. The cons of this Method lie in the considerable amount of time and = in the fact that the container is relatively thick-walled and so it must be expensive, since it is not at the high temperatures may collapse under vacuum. -

The aforementioned method can be used to reduce the oxygen content of pre-alloyed powders of the G-type "High-speed steel" M 2 "should be suitable. The in steels of the 2yps of M 2 formed oxides are oxides of Fe, W, Mo, Cr and V. All these oxides, with the exception of Ghroiu- and vanadium oxides, because of their relatively low levels

-a-

Reduce educational energy quite easily. Since a steel of the type M 2 contains only about 4 $ chromium and -2 $ vanadium, a reduction of the oxides by means of carbon at about 1200 ° C. can certainly be carried out if sufficient reaction time is available. On the other hand, * include all other fast turning tools, Heißgesenkstähle, cobalt. Based tool and structural alloys. '■ and based ITi disgust ■ "superalloys ¹¹ much larger amounts of reactive elements such as Cr, V, 21, Al, etc. . so that a removal of oxides by carbon by the just-described V _e rfahren is extremely difficult.

Common heat-resistant tool, die, and building materials are made by a number of different processes, such as: B. through immediate Shaping by casting, forging or rolling or by powder metallurgical processes. The main concern A component of these alloys can be iron, nickel and / or Cobalt, and as a solidifying agent can be a great one Variety of other alloy elements can be added. However, all of these substances have one characteristic in common! They all contain additives of reactive metals. A "reactive metal" is understood to mean elements whose Oxides or oxides are characterized by a high energy of formation. In other words, the oxides of reactive metals can be increased with increasing energy of formation worse to reduce to metallic state. For the Purposes of explaining the invention. It is assumed that a formation energy of -40 keal / gram-atom of oxygen S16 C the boundary between reactive and non-reactive Represents metals. As an example it can be said that?

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MoO, kcal with an energy value von'- 32 / gram atom by Hp or other reducing agents still "on: comparatively low temperatures, for example, 8 of the Basic Law can be reduced, while Al ₂ 0" with an energy of formation of -.?. 95 kcal / gram atom can only be reduced at extremely high temperatures.:

A review of the summary lists of the known heat-resistant tool, die and construction alloys shows that all of these alloys contain chromium (-58 kcal / gram atom). The list of ■ "thirty commercial high-temperature alloys." Based on nickel shows a range from 10 to 27 ¹ P chromium. The corresponding list of the heat-resistant cobalt-based tool alloys on the market shows a chrome range from 18.5 to 31 $ «All twenty-nine commercially available high-speed steels (AISI series 2 and K contain 3» 75 to 4 »25 ^C A chrome , and the eighteen AISI Type H hot die steels contain from $ 2 to $ 12 of this reactive element.

Chromium is added to alloys mainly because of its favorable influence on the oxidation resistance and, in the case of tool steels, because of its property of giving a moderate increase in the hardening depth. The main disadvantage of this element is that its oxides are extremely difficult to remove by chemical methods. But other reactive elements such as Al, lib, Mn, Si, Ta, Ti ₉ V, Zr etc. are added to almost all heat-resistant alloys based on iron, cobalt and nickel. These elements generally promote the strength and wear resistance of the alloy, but, like in the case of chromium, their oxides are extremely difficult to machine. ·

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Alloys with buckets; of reactive He full ■ "possess d ^ e further limitation that during the üciunelzeno the reactive elements present an additional ^ chuvz of the atmosphere and that they also:, iit the usual high-firing furnace linings such as -one '_ \'; c, Magnesia, silica, etc. react. This means de3 an inert atmosphere, such as 3. Argon or Yakuu:.: Be; .r. Melting can be used nut, and that also besides order, τ- | f borrowed resistant coating materials (.oeryilerce, 'Thorerde, Zirkonerde) must be used if nicrrj: even melting by means of an electric arc process in eir.en. . V / water-cooled copper furnace carried out v / ercen mu2. . ^ orr.ii; all special Schnielz procedures have quite obvious ones economic disadvantages.

The invention avoids the disadvantages and limitations outlined above that exist in all of the heat-resistant alloys known to date. It specifies metal oil powder of a novel composition, which is easy to apply. full; It V / erkst off-density compact and a whole new family of y malleable, heat-resistant non-oxide * "tool and structural alloys form.

; According to one aspect of the invention, a heat-resistant, easily deformable, oxide-free alloy is provided which can withstand a cutting edge under the high temperatures encountered in machining processes and "withstands softening" at temperatures of more than 5JO 0. This alloy contains 0.5 to 4 fi carbon, from 5 to 60 S ^ nonreactive carbide and the parent metal sis residue. by "non-reactive" Karbidbildoern are thereby in the sense of the above-discussed

² i ¹ .. ¹ . ^{7th 7} :: _: BAD

Definition elements such as tungsten and / or molybdenum understood, while the "term" G-Rundmetall "Sicen, ' Cobalt, and / or liiclcel are understood to be 7nit the common natural impurities. ■ '-

The alloys assembled according to the invention can be hardened to a hardness of more than Hc 56, and they are characterized by an ultra-fine, very homogeneous Microstructure made of, which does not move below about 1230 ° C much coarser. But above all, these are alloys free of embrittling oxides, so that there are possibilities for higher cutting speeds and better abrasion resistance result. Your carbide volume is higher, and they also contain major amounts of alloy tarnish parts such as tungsten and molybdenum which have the high temperature strength improve the materials significantly. All in all the alloys according to the invention are harder than all previously known tool or Senkf om alloys Iron, iTickel and / or Eobalt base, be these now cast or forged. The efficiency as a cutting tool is in the invention Alloys with the performance of conventional high-speed steels far superior. It was also found that the alloys according to the invention an excellent cooking range have a very high flexural strength, exceptional response to heat treatments and very good machinability. Moreover, they let themselves Manufacture with powder metallurgy at very low cost «.

The invention relates not only to tool or die forms, but also - in another aspect of the invention - also on building alloys that are used in all the cases used in

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. who need great strength at high temperature. In the case of building alloys, the carbon content is the alloy composition is decreased to reduce the hardness of the alloy to Rc 55 or less and at the same time to increase the toughness. The "solid solution solidification", Which is caused by the high tungsten and molybdenum levels, results in alloys that last long periods of time withstand heavy mechanical loads at elevated temperatures of above approx. 370 ° C can. In addition, these building alloys are due Their ultra-fine microstructure easily turns into forgings thermoformable, while the corresponding conventional Alloys z. B. are made by casting, can not easily be deformed hot.

Regardless of the special composition within the range defined above, all alloys according to the invention have in common that they start from a fine powder of the final alloy composition, which is characterized by a fine dispersion of the carbides in a solid, fine-grain matrix, and this easily by hot compression can be compressed into an oxide-free material that corresponds in its density to the density in the as-cast state, - / ^r

It is an essential feature of the ^ invention that the pre-alloyed powders and the compacted materials only the "non-reactive" alloy components included, "in which the educational energy of the Formation of oxides at 816 ° G low? is-t than - 40 kcal / gram Atom of oxygen. Accordingly, the "reactive" Elements defined as such, their reaction products with Oxygen has an energy of formation of - »4-1 to - ^ 100 and more kcal / gram ^ atom possess ^ examples of reactive and non->

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reactive elements are the following:

Oxides of "reactive"
Elements Educational energy
816 ° C - V ₂ O ₅ . -
------. ■ - "-
- 48 kcal / gram-atom 0 Cr ₂ O ₃
Ob ₂ O ₅
MnO • - 58 "
.-. 62 "
- 66 V. Ta ₂ O ₅ /
SiO ₂ -. - 67 "
- 72 "■■ - ■ '■ ■' - '; ■■ TiO ₂ - 8OJ ' Al ₂ O ₃ ■ - 95 »

Oxides of "non-reactive" elements.

Formation energy at 816 ⁰ C

NiO CoO MoO

3 4

- 27 kcal / gram atoin 0 -27 "

- 32 "

. - 33 ": - - ■■ - ■ -38 ·" ■■■ - ^■;.

The invention extends to 'further on a retracts, for the production of heat-resistant non-oxide tool and structural alloys which is characterized characterized in that pre-alloyed powder having the composition 0.5 to 4 $> carbon, 5 to 60 · $ iarbidbildner of non-reactive and the remainder of the base metal in the form of iron, cobalt and / or nickel, which is the in

these powders contain oxygen compounds practically be completely reduced, and that the powders then become one oxide-free, completely-'dense alloy material are compressed.

The inventive method :: ⁵ is based on the knowledge that ketal powder of the defined composition,

& which consequently contain no "reactive" elements such as chromium, vanadium, ITiobium, tantalum, titanium, silicon, manganese and aluminum, by means of which carbon present in the alloy as a reducing agent is very easily cleaned and freed from oxide films ". For carrying out the invention In the process, the pre-alloyed powders can be placed in a thin-walled canister or a corresponding container and compacted with this container at temperatures in the range of about 900 ° C to 11 50 ° C. A small opening can be provided in the container to allow gases such as CO and CO ₂ to escape. However, such an opening is not absolutely necessary, and it is also not necessary for the containers to be evacuated "Powder in stick form and subsequent ^ removal of the container material. Alternatively, this can also be done Heated powders in the containers are compacted by hot pressing with subsequent forging and rolling, after which the casing is removed again.

It has also been found that those powders which have low softening temperatures can be filled not in containers for the "purpose of removing film

is absolutely necessary. For example, the pre-alloyed powder in the case of the tool steel powder can be used as well the building alloy powder based on cobalt and kickel as well as also in the case of some cobalt-based tool alloy powders that are tempered in the temperature range from about 760 ° C to Ms 930 ° C can be cleaned and softened by it in one step in a reducing atmosphere to the x'emper temperature be heated. The reducing atmosphere can e.g. B. from hydrogen, cracked ammonia, hydrocarbon gas such as methane, a mixture of CO + COp or the like exist. After tempering and slow cooling can the pulveij at room temperature by cold pressing formed into easy-to-machine blocks. The blocks are then heated to about 1090 ° C in a protective atmosphere of nitrogen, argon or the like. And then extruded into a 100% dense rod-shaped material. Alternatively, the blocks can also be hot-pressed to form an approximately 95 to 97% dense material are then compacted by forging and / or hot rolling to a one hundred percent dense material is further compressed.

An essential advantage of the inventive method is that the vorlegiertön powders ⁱ then compressed to a fully dense oxide-free material, may be prepared by a simple, with only a small cost, working sputtering. This is because water can be used to break up the melt flow of the master alloy and also to collect the solidified droplets; an inert gas is not required. The use of water has

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apart from the cost savings, but also as a result, ■ that the quenching speeds are much higher, which leads to an improvement in the microstructure of the powder. The remaining on the individual powder particles Oxide films can be easily reduced at moderate temperatures (769 to 930 C), leaving out atmospheres z. B. cracked ammonia can be used that very cost much less than inert gas atmospheres such as B. argon or helium. An additional benefit is the Case of pre-alloyed powders with low tempering temperature in that the. the treatment with a reducing Gas to remove the oxides at the same time also anneals the powder so that it can be deformed while cold. Cold formed blocks these alloys can be extruded directly or extrusion without a casing with a Container and a subsequent removal container material necessary '. But it is particularly important in everyone This has the advantage that oxide-free alloys are obtained which have an ultra-fine, uniformly distributed carbide phase and which allow the manufacture of otherwise impossible forged materials. They are bigger ones Volume fractions of disperse phase or larger contents on Festlösüngs-Verfestigern possible without a Loss of workability or toughness.

The invention is explained below on the basis of a number explained in more detail by examples.

In all examples, materials became more diverse Composition melted and using an atomization technique pulverized. The powders were then put into a Tightly sealed container and brought by hot compression to a completely tight, oxide-free material condensed. Typical examples of the composition of the materials used are given in Table I below.

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a b e 1 le

Composition in percent by weight

alloy Fe 7th Co Ni ί - V / Mon C. H
(Te + Co + Ni) V / + MO - Λ76 - 7th 45 - 47.25 5 2.75 45 • 52, 25 A81 - '62, 5 - - 1 ° 25th 2.5 62.5. 35 A82 - 7 ^Λ 37, 5 10 - 45 5 2.5 47.5 50 ΑΘ3 - 7th 42 »5 20th 10 25th 2, 5 62, 5 35 A88 - ■ 1 52.25 - - 15th 30th 2.75 52.25 45 A90 - 7th 37.5 10 - 30th 20th 2.5 47.5 50 : A91 - 7th 37.5 10 - 35 15th 2.5 47.5 50 ; A1 06 _x - 9 57, 5 - 10 - 40 2, 5 57.5 40 ; At the - 2 47.5 - 10 10 40 2.5 47.5 50 • A113 - 2; 56.5 - - - ".. 40 3.5 56.5 40 A114 - 33 47.5 - 50 2.5 47, 5 50 _; A1 36 58 2 20th - 20th - 1.3 78.7 20th A137 38, 40 "- 20th - 1.3 78.7 20; A1 38 - 53.7 - 20th 25th 1.3 53.7 45 A144 48, 30th - 20th - 1, 3 78.7 20th , A145 33, 45 - 20th 1.3 78.7 20th \ A146 '' 28, 50 - 20th - 1V3 78.1 20th ! A147 38, 40 10. 10 1.3 78 _% 7 20th A1 51 38, 40 - " 20th 1.3 78, 7 20th • A152 38, 39.9 19 «9 - 1-13 78 ,. 8th 19.9 A1.62 38, 40 - 20th ..1.8 78, 2 20th A163 39 40 - '. ", 20th 0.8 79.2. 20th A164 38, 40 20th - 1.67 78.33 20th A165 39 40 20th 0.8 79, 2 20th A169 34 34.7 ■■ = ■ 30th 1.3 68.7 30th A170 34 34.7 30th -. 1.3 68.7 30th A171 34 34.7 20th - .1,3 78.7 20th 1172 34 34.7 f. 20th 1.3 78.7 20th

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The method according to the invention will now be explained in more detail using the specific example of the production of the alloy λ 138 listed in Table I. For the other alloys contained in Table I, the same statements apply accordingly.

. In order to produce a sufficient batch of alloys of, for example, 2.5 kg, the individual components initially in the correct proportions (in the case of the alloy A138 so 53.7 $ Co, 2Ö # W, 25 ^ Mo and 1.3 ^ C) balanced ' and in an induction furnace (or other suitable Melting furnace) melted. Then the melt was in atomized and quenched using a conventional atomizer. The atomizer was except for the melt stream charged with a high pressure inert gas stream and contained a water bath at the bottom as a collecting medium Melt stream was broken up into numerous fine droplets within the atomizer, which were carried by the Inert gas flow and then rapidly cooled (quenched) in the water bath. They are in the water bath accumulating fine particles - were then dried, they formed the powder used as the starting product for the next process step.

The oxygen content of the powder produced in this way was on the order of 500 to 1000 ppm (ropes per million). It should be noted at this point that the .above described manufacturing process of the powder while the preferred method is that, of course, so is that other methods of making the master alloy powder Can be used provided these other methods provide the required ultrafine microstructure of the powder particles result. .;.

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For the production of a compacted memory material the powder first became In from the master alloy powder. a sealed container made of "Inconel" locksmith. The container was not evacuated and also did not contain any measures for the removal of gases, which are in the following Can form processing steps for example. The container was closed by welding.

The sealed container would then open heated to a temperature of about 1120 ° G and then one Subject to forging process. For forging vmrdeim considered ' Example of a mechanical forging unit of un-, about 110 kg. Capacity used that with one open jaw and an edger worked. The forging led into pancake-like blocks about 1 to 1.5 cm thick.

After forging they were in the containers -enclosed blocks, to a thickness of approximately 0.55 to ■ 0.61 hot rolled, with a reduction in thickness of 10 ^ b was intended for each roller pass. This gives a total Thickness reduction of about $ 90 to $ 92 based on that Starting thickness of the blocks. After the; hot rolling, that became Hardening material 'removed, and the remaining plate-shaped Material was examined for its metallurgical and mechanical properties.

A visual examination of microphotographs of the plate-shaped material showed that the material was free of oxides and had an ultra-fine microstructure. Also in terms of hardness and heat resistance were very good, the properties of the material, as is clear from s f oil · by the figures,

-.: MD

Hardness in the rolled state lic 60. 6

Hardness after aging ".

1288 ° C Rc 66.6

Coarsening temperature 1288 ° C

By reducing the carbon content of the alloy A138 (z, B, 'fi 0.5 C), the hardness drops to a level below 56 Rc, whereby the alloy as well 3aulegierung is usable. It is easily heat-workable and can withstand heavy mechanical loads at elevated temperatures above 370 ° G even over long periods of time. This is due to the "solid solution solidification" caused by the high content of Vfolfram and Holybdun.

The alloys according to the invention were examined for their hardness, and the bending strength was also determined by means of bending tests at room temperature. The results of these investigations ¹ are set down for some alloys selected as typical examples in (Table ^ II.

; T abe 1 1 e. II

properties some alloys alloy Hardness (Rc) Bending strength (kg / cm) A 76 63.0 18 580:. ■; A 82 ■■ ■■ 62.2 23 410 - ■: λ A 91 61.1 19 910 A 137 :: '■' 72.0 19 580 '- A 146 _ 66.0 36 460 A 1 51
'' ■ · ■ "■ ' : ·' ■ 19 840 V -V. ...... .. Λ - .. $% - ~ YES A- Wj, -n ~ - - - τ r -_-- ~ "■ _r ----- - ■ _-- .- - ,.; - χ, - ._ · ■ -
\ ⁴ r ^{i: l!} ' BAD ORIQINAL

The figures set out in Table II

indicate that the alloys of the invention are excellent Strengths and high levels of hardness have ::, consequently are therefore well suited as tool alloys. '

Furthermore, machining investigations were carried out, in-which the lifespan of individual inventions Alloy-made tools was tested. The material to be machined was Inconel 71b, a commercially available one Superalloy widely used for jet engines and which, according to current knowledge, are among the most difficult to machine materials ■ counts. All tools made from the alloys of the present invention were compared to one of the best currently "known commercially available Werkzeugatähl6, namely the type M43 »which has the following composition:

8.7 # Mo 2.0 io V.

1.8 JiW V 8.2 $ Co

3 »75-75 Cr * 1.23 # G remainder Ee.

Each of the tools used in the research was ground to the same dimensions and then used to cut a test bar made of Inconel 713 in clamped a test lathe. The test bar would run at about 7.5 m / min using conventional coolant Surface velocity, approximately 0.159 cm depth of cut and machined about 0.0127 cm per revolution of feed. A wear mark of set about 0.076 cm on the tool. The test results are selected for some examples of those according to the invention Alloys in comparison to high-speed steel H 43 listed in Table III.

■ - OO ^ fi 1? / -1 1 7 7 - "'

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ΐ hurry up ΙΓ

Zerspanurigs-x'est au.f lathe 'mit.Inconel 713 »^ JiI. *

Tool from heat treatment Service life (min) Reading ITr.

H45 approx. 1200 ⁰ C, 4 min 6 - salt hardening

■ 566 ° C, 5 min

■■■ '■ :. 524 ° C, 2 hours - -. . ■ '+ 2 St. + 2 St.

A 138 - ■ ": ■. ■■; ■; 704 ° G, 25 hours 9

Λ 136 12Ud _- ⁰ C, 3 min 34

Oil hardening

"■■. ■■: 538 ° C, 2 St -r 2 St.

A 137 1288 ⁰ C, 3 min

:: Oil hardening 52

. ; ■■■ 538 ° C, 2 hours +2 hours

Similar machining tests were carried out for the alloys At36 and A1 37, with a titanium alloy having the composition as the material to be machined. :. ;

; 6 ^ aluminum '4 # vanadium

; ; Rest of titanium:

would be used. The was again used as a reference material High-speed turning tool M 43. The material to be machined was in

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Bar shape before and became with a surface speed of 22.5 m / rain, a cutting depth of C, 159 cn 'and one Feed from C, Oi 27 cnr per "Jradrehunt; machined. Aic end point the V / Erkseug service life became a wear mark of 0.152 cm used. The results of these investigations are given in Table IV.

Table IV

Machining test on a lathe with (Ti - 6Ai - 4 V)

Rc 36

ϊ / tool from heat treatment service life Alloy no.

M43 approx. 1200 ⁰ C, 4 min 'Ί 7

Salt hardening

. 566 ° C, '5 min

524 ° C, 2 hours • + 2 hours + 2 hours

A 136-1288 ° G 3 min 49

Oil hardening

566 ° C / 2h + ^ 2_h

A 137 1288 ⁰ G., 3 min 57

Oil hardening

^Q Q ₁ 2 hours + 2

Those set out in Tables III and IV Data show that the alloy according to the invention

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Use for high-speed turning tools even when machining of commercially available materials that are extremely difficult to machine have excellent tool life. These alloys according to the invention are oxide-free, complete Powder products compacted to the density of the as-cast state, which have good hardness and good heat stability (Iiohe Coarsening temperature). If such alloys can be prepared by conventional methods these are not easily thermoformed, while the alloys according to the invention are readily deformed by warning can be processed into forged products.

■ .'- ■ 'The alloys A1 36 and A1 37 can be tempered, so that cold pressing can be carried out. By Forging and rolling in bar form - ". Material;; turned out to be of excellent quality. The alloy A 136 showed a coarsening temperature of 1274 ° G, while an even higher coarsening temperature was found for alloy A137. The ultra-fine carbide particle size this latter alloy was after one Hour at 1288 ° G still unchanged. Both alloys speak of quenching type hardening treatments and tempering "similar to common high-speed reli steels. In? All of the alloy A 137 had a maximum hardness of Ra 83 (Rc 7.2) achieved. This value is higher than that Hardness of all commercially available known high-speed steels " or iCobalt-based tool alloys, that's enough into the hardness range of sintered carbides. ■

KRE / Gfz - claims -

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Claims (1)

P ate η t a η s ρ r ü ehe 1. Heat-resistant, oxide-free alloy, marked. by a composition (in percent by weight) essentially . from 0.5 to 4.0 ^ carbon and $ 5.0 to $ 60.0 tungsten and / or molybdenum and remainder iron and / or, and / or cobalt, being the constituents, the usual natural impurity may contain. 2. Alloy according to claim 1, characterized in that the microstructure has fine carbides evenly distributed, and that the alloy is easily thermoformable. 3. Alloy according to claim 1 or 2, characterized gekenr, ζeiehr, et that the alloy has a hardness above Rc 56, holds a cutting edge below the high temperatures occurring during machining, and resists softening at temperatures above 530 °. 4. Alloy according to claim 1 or 2, characterized in that the alloy has a hardness below Rc 56 and withstands heavy mechanical loads at elevated temperatures above 370 ° C for longer periods of time. -. "■ '-'-. VTT ~~ ' —— -BAD' 1936023 5. Alloy according to one of claims 1 to 4-, d ⁿ by " j / - indicates that the alloy contains up to 90 $ iron and / or cobalt and / or liickel. .6. A method of making an alloy according to any one of the preceding claims, characterized in that a prealloyed powder of the composition from 0.5 to 4.0 pounds of carbon
P and 5 '0 to 60.0' / o V / olfrrnn and / or Molybdilu and remainder iron and / or cobalt and / or n'ic ^ c-i is produced, the CauerstoiT- 'efttrltenen in the powder connections are essentially completely reduced, and then the powder into a completely, dipthen work piece! ' is compressed. ifÄi ™? * ' 7. The method according to claim 6, characterized in that άιΖ ' ■ "the pre-alloyed powder by-rapid quenching a atomized melt produced, v / p with the degree of atomization of the melt selected so that laindestona 75 # of the powder passed through an 80-mesh sieve. 8. The method according to claim 6, characterized in that for removing the oxides from the powder, the powder is filled into a container and inside the container on a
Temperature of about 900 ° C to 1150 ° C is heated. 9. The method according to claim 8, characterized in that
the heated powder in the container is extruded into the shape of a solid rod. BATH T7T "7— 1 O. A method according to claim 8, characterized instructive marked in e ζ, t ο that aas erhitate powder in the container to a hot pressed vollGt ^ ^ dense UDI '' Verlestoff, gesclpiedet and £ .EV; ai.rv wlrä. 11. The method of claim 6, wherein the pre-alloyed powder has a χ-einper exwa temperature below 930 ° G, ά3durch gekenη ze ichnet that the oxides of the powder in the powder 'I'emperaturen id range of about' / 60 to remove ° to 950 ° C is treated in a reducing gas atmosphere. 12. The method according to claim 11, characterized ge Ic e η η ζ eic hr, et that the powder is cold-pressed after removing the oxides into a block and the block is then heated in a protective atmosphere and extruded into a solid rod. 13 · Verfahr eti according to claim 11, c. -; cur ch geke η η ζ eic lan et, LzQ ' the oxide-free powder is cold-pressed into a block, is u.id " . - the block is then compacted to a completely dense Vverkstoff by hot pressing, boiling and vialing. 14. Pre-alloyed powder for the production of heat-resistant, oxide-free tool or construction alloys, thereby gelcennzeich . net that the powder essentially has a composition (in percent by weight) from $ 0.5 to $ 4.0 carbon ^ and 5 * 0 to 60.0 yes tungsten, and / ο the molybdenum and remainder iron and / or i-nickel and / or cobalt owns, easily into a completely dense, oxide-free solid material is compressible and in its microstructure a uniform distribution of fine carbides in a solid, fine-grained igen, JIa ^ r i3C. 009012/1 177 - ■ - ■ -.- BATH