US20040154705A1 - Fastening element made of carbon-containing steel and method for the production thereof - Google Patents
Fastening element made of carbon-containing steel and method for the production thereof Download PDFInfo
- Publication number
- US20040154705A1 US20040154705A1 US10/480,882 US48088203A US2004154705A1 US 20040154705 A1 US20040154705 A1 US 20040154705A1 US 48088203 A US48088203 A US 48088203A US 2004154705 A1 US2004154705 A1 US 2004154705A1
- Authority
- US
- United States
- Prior art keywords
- fixing element
- functional tip
- martensite
- process according
- carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 13
- 239000010959 steel Substances 0.000 title claims abstract description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 9
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 9
- 238000000034 method Methods 0.000 title claims description 15
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 31
- 238000010438 heat treatment Methods 0.000 claims abstract description 23
- 238000000137 annealing Methods 0.000 claims abstract description 18
- 230000001939 inductive effect Effects 0.000 claims abstract description 14
- 238000007493 shaping process Methods 0.000 claims description 11
- 229910000975 Carbon steel Inorganic materials 0.000 claims description 4
- 239000010962 carbon steel Substances 0.000 claims description 4
- 238000005256 carbonitriding Methods 0.000 claims description 4
- 238000010304 firing Methods 0.000 claims description 4
- 238000010791 quenching Methods 0.000 claims description 4
- 230000000171 quenching effect Effects 0.000 claims description 4
- 238000005260 corrosion Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000011295 pitch Substances 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
- C23C8/22—Carburising of ferrous surfaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0093—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for screws; for bolts
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/28—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in one step
- C23C8/30—Carbo-nitriding
- C23C8/32—Carbo-nitriding of ferrous surfaces
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/80—After-treatment
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/42—Induction heating
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2221/00—Treating localised areas of an article
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Definitions
- the invention concerns a process for the production of a fixing element which has a hardened functional tip and comprises a carbon-bearing steel which after heating to austenitisation temperature and subsequent quenching forms martensite, wherein the fixing element is heated overall to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation. It further concerns a fixing element, in particular a screw having a screwthread-forming and possibly hole-forming shaping zone, the structure thereof comprising in part martensite and in part annealed martensite.
- Fixing elements which are to be driven into hard materials require a correspondingly hard functional tip.
- the functional tip can involve preferably in the present case—the shaping zone of a screw, which forms a counterpart thread and possibly pre-bores or flow-shapes the hole which is required beforehand.
- the functional tip however can also be the driving-in tip of a firing bolt fixed by a bolt-setting gun, or the cutting ring edge of a stamping rivet.
- screws comprising low-alloyed carbon steel (heat-treatable steel or case-hardening steel)
- screws of that kind are susceptible to hydrogen-induced delayed brittle fracture formation or stress crack corrosion.
- DE-AS No 22 11 608 to impart a very high degree of hardness to the screwthread-forming portion of a screw of that kind, such hardness extending only slightly into the screwthread core which in other respects is of a lower degree of hardness (but higher toughness).
- Induction hardening which is used in that respect admittedly permits the desired limited hardening effect to be achieved, but it requires individual treatment of the screws in an annular coil, which involves the corresponding expenditure of time and cost.
- disconformities are formed between that edge zone and the core structure, because at that location there is an unintended annealing effect in respect of inductive heating. Those disconformities can penetrate so far in the radial direction that they partially displace the heat-treated structure which is initially present there and in that way produce a torsional rupture-endangered cross-section.
- the invention seeks to provide simplified production without limitation of the range of uses of the fixing elements and also to afford a simpler structure of such fixing elements.
- the process aspect of the invention provides that the annealing operation is effected by inductive heating to a temperature above annealing brittleness and is limited to the region of the fixing element, which is outside the functional tip. That is based on the fundamental notion that the hardness of the martensite structure formed by the known austenitisation operation and subsequent quenching is sufficient for the purposes of use in relation to a hard counterpart material; in accordance with a development of the invention that hardness can be still further increased by recarburisation or carbonitriding in the region near the edge.
- the hardness of the martensite structure is not reduced again (in the interests of higher toughness) by heating the entire fixing element to the annealing temperature, and the functional tip—that is to say for example the screwthread-forming and possibly hole-forming shaping zone of a screw—is also not subjected to more extensive special treatment, but a heat-treated structure consisting of annealed martensite is produced in the remainder of the fixing element (for example the screw), which does not belong to the functional tip or the shaping zone, by virtue of partial short-term annealing by means of inductive heating; that heat-treated structure of annealed martensite, in the fixing condition, can withstand the stresses produced in that situation, without stress crack corrosion and brittle fracture formation.
- the annealing treatment in the furnace is eliminated and correspondingly reduces the manufacturing expenditure.
- martensite besides non-annealed martensite, is also used to denote unstressed and low-annealed martensite. That can be afforded if the fixing element is subjected for example to a tempering treatment (about 1800-220° C.) after galvanic coating or a baking/precipitation-hardening treatment (approximately 300° C.) in the context of a dip coating operation. In comparison heating to a temperature above annealing brittleness ( ⁇ 360° C.) results in (highly) annealed martensite.
- a tempering treatment about 1800-220° C.
- a baking/precipitation-hardening treatment approximately 300° C.
- the hardness of the functional tip can be further increased if at least the tip is recarburised or carbonitrided during heating to and holding at the austenitisation temperature.
- the edge hardness of the functional tip/screwthread-forming zone can thereby be increased to 750-950 HV0.3, with a core hardness of 350-650 HV0.3. If the region of the fixing element, which is outside the functional tip, is also recarburised or carbonitrided, that affords overall four regions of different hardness levels, more specifically two in the axial direction (tip/shank) and two in the radial direction (edge/core).
- Preferred inductive heating of the fixing elements in a continuous-heating procedure through a line inductor permits a high treatment speed and a correspondingly high output which further reduces the additional costs of such fixing elements, in comparison with conventional fixing elements of the same quality.
- the functional tip is advantageously cooled—for example in a water bath—in order not to adversely affect its hardness, by virtue of heating to the annealing temperature.
- the functional tip is formed by an at least screwthread-forming shaping zone.
- the shaping zone can also be continued to the screw tip in a hole-forming portion, that is to say a boring portion or a flow hole-forming portion.
- the fixing element can also be a firing bolt fixed by a bolt-setting gun or a rivet, in particular a stamping rivet.
- a fixing element according to the invention with a hardened functional tip comprising a carbon-bearing steel whose structure is in part martensitic and in part annealed martensitic, wherein the functional tip is martensitic throughout and the remainder of the fixing element comprises a martensite annealed by short-term inductive heating.
- the functional tip consisting of martensite has the high level of hardness required for driving the fixing element into a hard counterpart material, while the annealed martensite of the remainder of the fixing element (as a consequence of the short-term inductive heating thereof to the annealing temperature) has a notched bar toughness which allows it, even under stress, to withstand being endangered by hydrogen-induced brittle fracture formation or stress crack corrosion.
- martensite besides non-annealed martensite, is further used to denote unstressed and low-annealed martensite.
- a wire portion (bar) of low-alloyed carbon steel such as SAE 1018/18B3/16MnCr5 (which can be case-hardened with recarburisation or carbonitriding) or SAE 1022/22MnB4Cr/35B2/34CrMo4 (which can be heat-treated) or a high-alloyed carbon-bearing steel such as for example X20Cr13 or X38CrMoV15 (that is to say stainless steel) is upset at one end to form a screw head.
- a bore-forming part or flow hole-forming part of the functional tip is formed on the other end by squeezing. Then, a screwthread is rolled on to the shank which is therebetween.
- the initial threads serve for forming the thread and belong to the shaping zone which forms the functional tip.
- the rough screw is then heated to austenitisation temperature in the furnace and, depending on the respective material/dimensioning/furnace type, maintained at that temperature for 10 to 60 minutes; in that case, case-hardenable steel can be recarburised or carbonitrided.
- the screw is then quenched in water or oil.
- the portions of the screw which lie outside the functional tip are inductively heated to an annealing temperature in a linear inductor for 3 to 60 seconds, while at the same time the functional tip is cooled, for example in a water bath.
- the screw can be coated for the purposes of corrosion protection.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Connection Of Plates (AREA)
- Gripping Jigs, Holding Jigs, And Positioning Jigs (AREA)
Abstract
A fixing element which comprises carbon-bearing steel and has a hardened functional tip is overall heated to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation which is effected by inductive heating and limited to the region of the fixing element, which lies outside the functional tip. In that way the structure of the fixing element comprises in part martensite and in part annealed martensite, wherein the functional tip comprises throughout martensite and the remainder of the fixing element comprises a martensite which is annealed by short-term inductive heating.
Description
- The invention concerns a process for the production of a fixing element which has a hardened functional tip and comprises a carbon-bearing steel which after heating to austenitisation temperature and subsequent quenching forms martensite, wherein the fixing element is heated overall to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation. It further concerns a fixing element, in particular a screw having a screwthread-forming and possibly hole-forming shaping zone, the structure thereof comprising in part martensite and in part annealed martensite.
- Fixing elements which are to be driven into hard materials require a correspondingly hard functional tip. The functional tip can involve preferably in the present case—the shaping zone of a screw, which forms a counterpart thread and possibly pre-bores or flow-shapes the hole which is required beforehand. The functional tip however can also be the driving-in tip of a firing bolt fixed by a bolt-setting gun, or the cutting ring edge of a stamping rivet.
- In the case of screws comprising low-alloyed carbon steel (heat-treatable steel or case-hardening steel), it is known for them to be hardened and annealed in continuous-heating furnace installations or case-hardened and annealed, with recarburisation or carbonitriding. In particular after subsequent galvanic coating, screws of that kind are susceptible to hydrogen-induced delayed brittle fracture formation or stress crack corrosion. It is also known from DE-AS No 22 11 608 to impart a very high degree of hardness to the screwthread-forming portion of a screw of that kind, such hardness extending only slightly into the screwthread core which in other respects is of a lower degree of hardness (but higher toughness). Induction hardening which is used in that respect admittedly permits the desired limited hardening effect to be achieved, but it requires individual treatment of the screws in an annular coil, which involves the corresponding expenditure of time and cost.
- Finally, it is also known for thorough or penetration hardening of a screw consisting of heat-treatable steel (heating it and holding it for a prolonged period of time at the austenitisation temperature and then quenching in water or oil) with subsequent annealing, to be followed by inductive hardening which is limited to the shaping zone, by a procedure whereby the outer edge region of the shaping zone is briefly heated again to the austenitisation temperature and freshly quenched. As a result, in this case also, only that edge region is transformed to hard martensite while the core retains the lattice structure of the annealed martensite produced by the preceding annealing operation. It will be noted however that disconformities are formed between that edge zone and the core structure, because at that location there is an unintended annealing effect in respect of inductive heating. Those disconformities can penetrate so far in the radial direction that they partially displace the heat-treated structure which is initially present there and in that way produce a torsional rupture-endangered cross-section.
- In place of the generally multi-stage and at any event complicated and expensive process for the production of a fixing element with a hard functional tip, the invention seeks to provide simplified production without limitation of the range of uses of the fixing elements and also to afford a simpler structure of such fixing elements.
- The process aspect of the invention provides that the annealing operation is effected by inductive heating to a temperature above annealing brittleness and is limited to the region of the fixing element, which is outside the functional tip. That is based on the fundamental notion that the hardness of the martensite structure formed by the known austenitisation operation and subsequent quenching is sufficient for the purposes of use in relation to a hard counterpart material; in accordance with a development of the invention that hardness can be still further increased by recarburisation or carbonitriding in the region near the edge. Then the hardness of the martensite structure is not reduced again (in the interests of higher toughness) by heating the entire fixing element to the annealing temperature, and the functional tip—that is to say for example the screwthread-forming and possibly hole-forming shaping zone of a screw—is also not subjected to more extensive special treatment, but a heat-treated structure consisting of annealed martensite is produced in the remainder of the fixing element (for example the screw), which does not belong to the functional tip or the shaping zone, by virtue of partial short-term annealing by means of inductive heating; that heat-treated structure of annealed martensite, in the fixing condition, can withstand the stresses produced in that situation, without stress crack corrosion and brittle fracture formation. The annealing treatment in the furnace is eliminated and correspondingly reduces the manufacturing expenditure.
- In this respect, the term martensite, besides non-annealed martensite, is also used to denote unstressed and low-annealed martensite. That can be afforded if the fixing element is subjected for example to a tempering treatment (about 1800-220° C.) after galvanic coating or a baking/precipitation-hardening treatment (approximately 300° C.) in the context of a dip coating operation. In comparison heating to a temperature above annealing brittleness (≧360° C.) results in (highly) annealed martensite.
- The hardness of the functional tip can be further increased if at least the tip is recarburised or carbonitrided during heating to and holding at the austenitisation temperature. The edge hardness of the functional tip/screwthread-forming zone can thereby be increased to 750-950 HV0.3, with a core hardness of 350-650 HV0.3. If the region of the fixing element, which is outside the functional tip, is also recarburised or carbonitrided, that affords overall four regions of different hardness levels, more specifically two in the axial direction (tip/shank) and two in the radial direction (edge/core).
- Preferred inductive heating of the fixing elements in a continuous-heating procedure through a line inductor permits a high treatment speed and a correspondingly high output which further reduces the additional costs of such fixing elements, in comparison with conventional fixing elements of the same quality. During inductive heating of the remaining length of the fixing element, that is to say all portions thereof which are outside its functional tip, the functional tip is advantageously cooled—for example in a water bath—in order not to adversely affect its hardness, by virtue of heating to the annealing temperature.
- If the fixing element is a screw the functional tip is formed by an at least screwthread-forming shaping zone. The shaping zone however can also be continued to the screw tip in a hole-forming portion, that is to say a boring portion or a flow hole-forming portion. In a comparable manner however the fixing element can also be a firing bolt fixed by a bolt-setting gun or a rivet, in particular a stamping rivet.
- In a corresponding manner a fixing element according to the invention with a hardened functional tip comprising a carbon-bearing steel whose structure is in part martensitic and in part annealed martensitic, wherein the functional tip is martensitic throughout and the remainder of the fixing element comprises a martensite annealed by short-term inductive heating. The functional tip consisting of martensite has the high level of hardness required for driving the fixing element into a hard counterpart material, while the annealed martensite of the remainder of the fixing element (as a consequence of the short-term inductive heating thereof to the annealing temperature) has a notched bar toughness which allows it, even under stress, to withstand being endangered by hydrogen-induced brittle fracture formation or stress crack corrosion. In this respect in this case also the term martensite, besides non-annealed martensite, is further used to denote unstressed and low-annealed martensite.
- A wire portion (bar) of low-alloyed carbon steel such as SAE 1018/18B3/16MnCr5 (which can be case-hardened with recarburisation or carbonitriding) or SAE 1022/22MnB4Cr/35B2/34CrMo4 (which can be heat-treated) or a high-alloyed carbon-bearing steel such as for example X20Cr13 or X38CrMoV15 (that is to say stainless steel) is upset at one end to form a screw head. A bore-forming part or flow hole-forming part of the functional tip is formed on the other end by squeezing. Then, a screwthread is rolled on to the shank which is therebetween. The initial threads serve for forming the thread and belong to the shaping zone which forms the functional tip.
- The rough screw is then heated to austenitisation temperature in the furnace and, depending on the respective material/dimensioning/furnace type, maintained at that temperature for 10 to 60 minutes; in that case, case-hardenable steel can be recarburised or carbonitrided. The screw is then quenched in water or oil.
- Thereupon, the portions of the screw which lie outside the functional tip (head, possibly the screwthread-free shank portion, and the holding pitches of the screwthread) are inductively heated to an annealing temperature in a linear inductor for 3 to 60 seconds, while at the same time the functional tip is cooled, for example in a water bath.
- Finally the screw can be coated for the purposes of corrosion protection.
Claims (14)
1. A process for the production of a fixing element which has a hardened functional tip and comprises a carbon-bearing steel which after heating to austenitisation temperature and subsequent quenching forms martensite, wherein the fixing element is heated overall to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation, characterised in that the annealing operation is effected by inductive heating to a temperature above annealing brittleness and is restricted to the region of the fixing element, which lies outside the functional tip.
2. A process according to claim 1 characterised in that a low-alloyed carbon steel is used as the carbon-bearing steel.
3. A process according to claim 1 characterised in that a high-alloyed carbon steel is used as the carbon-bearing steel.
4. A process according to claim 2 characterised in that at least the functional tip is recarburised or carbonitrided during the operation of heating to the austenitisation temperature.
5. A process according to one of claims 1 to 4 characterised in that the inductive heating operation is effected in a continuous mode through a line inductor.
6. A process according to one of claims 1 to 5 characterised in that the functional tip is cooled during inductive heating of the rest of the fixing element.
7. A process according to one of claims 1 to 6 characterised in that the fixing element is a screw and the functional tip is a screwthread-forming and possibly hole-forming shaping zone.
8. A process according to one of claims 1 to 6 characterised in that the fixing element is a firing nail or setting bolt.
9. A process according to one of claims 1 to 6 characterised in that the fixing element is a rivet, in particular a stamping rivet.
10. A fixing element which comprises a carbon-bearing steel and has a hardened functional tip and whose structure comprises in part martensite and in part annealed martensite, characterised in that the functional tip comprises martensite throughout and the remainder of the fixing element comprises a martensite annealed by short-term inductive heating to a temperature above annealing brittleness.
11. A fixing element according to claim 8 characterised in that the edge region at least of the functional tip is case-hardened as a result of recarburisation or carbonitriding.
12. A fixing element according to claim 8 or claim 9 characterised in that it is a screw and the functional tip is a screwthread-forming and possibly hole-forming shaping zone.
13. A fixing element according to claim 8 or claim 9 characterised in that it is a firing nail or setting bolt.
14. A fixing element according to claim 8 or claim 9 characterised in that it is a rivet, in particular a stamping rivet.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11/404,452 US20060185768A1 (en) | 2001-11-28 | 2006-04-14 | Fixing element comprising a low-alloyed steel and process for the production thereof |
| US11/519,417 US20070062620A1 (en) | 2001-11-28 | 2006-09-12 | Fixing element comprising a low-alloyed steel and process for the production thereof |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10158197.1 | 2001-11-28 | ||
| DE10158197A DE10158197A1 (en) | 2001-11-28 | 2001-11-28 | Fastener made from a low alloy carbon steel and process for its manufacture |
| PCT/EP2002/012943 WO2003046229A1 (en) | 2001-11-28 | 2002-11-19 | Fastening element made of a carbon-containing steel and method for the production thereof |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US11/404,452 Division US20060185768A1 (en) | 2001-11-28 | 2006-04-14 | Fixing element comprising a low-alloyed steel and process for the production thereof |
| US11/519,417 Continuation US20070062620A1 (en) | 2001-11-28 | 2006-09-12 | Fixing element comprising a low-alloyed steel and process for the production thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US20040154705A1 true US20040154705A1 (en) | 2004-08-12 |
Family
ID=7707158
Family Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US10/480,882 Abandoned US20040154705A1 (en) | 2001-11-28 | 2002-11-19 | Fastening element made of carbon-containing steel and method for the production thereof |
| US11/404,452 Abandoned US20060185768A1 (en) | 2001-11-28 | 2006-04-14 | Fixing element comprising a low-alloyed steel and process for the production thereof |
| US11/519,417 Abandoned US20070062620A1 (en) | 2001-11-28 | 2006-09-12 | Fixing element comprising a low-alloyed steel and process for the production thereof |
Family Applications After (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US11/404,452 Abandoned US20060185768A1 (en) | 2001-11-28 | 2006-04-14 | Fixing element comprising a low-alloyed steel and process for the production thereof |
| US11/519,417 Abandoned US20070062620A1 (en) | 2001-11-28 | 2006-09-12 | Fixing element comprising a low-alloyed steel and process for the production thereof |
Country Status (7)
| Country | Link |
|---|---|
| US (3) | US20040154705A1 (en) |
| EP (1) | EP1451378B1 (en) |
| AT (1) | ATE361999T1 (en) |
| AU (1) | AU2002352053A1 (en) |
| DE (2) | DE10158197A1 (en) |
| ES (1) | ES2286308T3 (en) |
| WO (1) | WO2003046229A1 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130302109A1 (en) * | 2010-12-20 | 2013-11-14 | Ejot Gmbh & Co. Kg | Screw made of low-alloy carbon steel, and method for producing such a screw |
| CN104197127A (en) * | 2014-09-17 | 2014-12-10 | 平湖市当湖街道飞天人机械图文设计服务部 | Connecting bolt of oil circuit of numerical-control lathe and process for thermally treating connecting bolt |
| CN104191560A (en) * | 2014-09-21 | 2014-12-10 | 金方明 | Injection molding machine base pressing plate and heat processing technology thereof |
| CN104197128A (en) * | 2014-09-17 | 2014-12-10 | 平湖市当湖街道飞天人机械图文设计服务部 | Bolt of oil circuit of numerical-control lathe and process for thermally treating bolt |
| CN104196851A (en) * | 2014-09-17 | 2014-12-10 | 平湖市当湖街道飞天人机械图文设计服务部 | Automotive body connector and heat treatment process thereof |
| CN104212964A (en) * | 2014-09-21 | 2014-12-17 | 金方明 | Injection molding machine pressing plate connecting piece and heat treating process thereof |
| CN104212962A (en) * | 2014-09-17 | 2014-12-17 | 平湖市当湖街道飞天人机械图文设计服务部 | CNC lathe hoisting system connecting element and heat treatment technology of CNC lathe hoisting system connecting element |
| CN104229229A (en) * | 2014-09-21 | 2014-12-24 | 金方明 | Connector for lifting mechanism of packing machine and thermal processing technique thereof |
| CN104227430A (en) * | 2014-09-17 | 2014-12-24 | 平湖市当湖街道飞天人机械图文设计服务部 | Lifting system base of numerical control lathe and thermal treatment technology of lifting system base |
| CN104227052A (en) * | 2014-09-17 | 2014-12-24 | 平湖市当湖街道飞天人机械图文设计服务部 | Turning tool outer cover of numerical control lathe and thermal treatment technology of turning tool outer cover |
| US11331703B2 (en) * | 2015-09-25 | 2022-05-17 | Nippon Steel Corporation | Piercer plug and method of manufacturing the same |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102007014408A1 (en) * | 2007-03-26 | 2008-10-02 | Ejot Baubefestigungen Gmbh | Self-tapping screw |
| DE102010063675A1 (en) * | 2010-12-21 | 2012-06-21 | Hilti Aktiengesellschaft | Screw |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4021274A (en) * | 1975-03-26 | 1977-05-03 | Russell, Birdsall & Ward, Inc. | Method for heat treating by induced current |
| US6213884B1 (en) * | 1999-10-20 | 2001-04-10 | Daimlerchrysler Corporation | Case hardened self-drilling, self-tapping, self-piercing fasteners and process for making the same |
| US20010014262A1 (en) * | 1999-11-15 | 2001-08-16 | Ejot Verbindungstechnik Gmbh & Co. Kg | Self-tapping corrosion resistant screw with hardened tip |
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| GB311337A (en) * | 1928-05-09 | 1930-08-08 | Ver Stahlwerke Ag | Process for the manufacture of articles, particularly screws and rivets, by upsetting in the cold |
| US3253495A (en) * | 1962-12-06 | 1966-05-31 | Huck Mfg Co | Hardened blind bolt with annealed shank portion |
| US3515602A (en) * | 1967-09-01 | 1970-06-02 | Alton W Gross | Method of making a self-locking screw |
| JPS5021153B1 (en) * | 1970-12-28 | 1975-07-21 | ||
| GB2186290B (en) * | 1986-02-11 | 1989-11-22 | Avdel Ltd | Pin for a fastener, and method of making same |
| ATE117742T1 (en) * | 1991-07-18 | 1995-02-15 | Daido Oxygen | SCREW MADE OF HARD STAINLESS STEEL AUSTENITIC STEEL. |
| DE4316753C2 (en) * | 1993-05-19 | 2002-01-24 | Thiele Gmbh & Co Kg | Middle chain conveyor with two-part scraper, especially double middle chain conveyor |
| US6086305A (en) * | 1999-01-13 | 2000-07-11 | Illinois Tool Works Inc. | Nails having selected heat treatment and hardening |
| US6109851A (en) * | 1999-01-13 | 2000-08-29 | Illinois Tool Works Inc. | Screws having selected heat treatment and hardening |
| US6386810B1 (en) * | 1999-05-21 | 2002-05-14 | Hiroshi Onoe | High strength screw |
-
2001
- 2001-11-28 DE DE10158197A patent/DE10158197A1/en not_active Ceased
-
2002
- 2002-11-19 WO PCT/EP2002/012943 patent/WO2003046229A1/en not_active Ceased
- 2002-11-19 DE DE50210135T patent/DE50210135D1/en not_active Expired - Lifetime
- 2002-11-19 US US10/480,882 patent/US20040154705A1/en not_active Abandoned
- 2002-11-19 ES ES02787727T patent/ES2286308T3/en not_active Expired - Lifetime
- 2002-11-19 AU AU2002352053A patent/AU2002352053A1/en not_active Abandoned
- 2002-11-19 AT AT02787727T patent/ATE361999T1/en not_active IP Right Cessation
- 2002-11-19 EP EP02787727A patent/EP1451378B1/en not_active Expired - Lifetime
-
2006
- 2006-04-14 US US11/404,452 patent/US20060185768A1/en not_active Abandoned
- 2006-09-12 US US11/519,417 patent/US20070062620A1/en not_active Abandoned
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4021274A (en) * | 1975-03-26 | 1977-05-03 | Russell, Birdsall & Ward, Inc. | Method for heat treating by induced current |
| US6213884B1 (en) * | 1999-10-20 | 2001-04-10 | Daimlerchrysler Corporation | Case hardened self-drilling, self-tapping, self-piercing fasteners and process for making the same |
| US20010014262A1 (en) * | 1999-11-15 | 2001-08-16 | Ejot Verbindungstechnik Gmbh & Co. Kg | Self-tapping corrosion resistant screw with hardened tip |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014506287A (en) * | 2010-12-20 | 2014-03-13 | エヨット ゲーエムベーハー ウント カンパニー カーゲー | Low alloy carbon steel screw and method of manufacturing the screw |
| US20130302109A1 (en) * | 2010-12-20 | 2013-11-14 | Ejot Gmbh & Co. Kg | Screw made of low-alloy carbon steel, and method for producing such a screw |
| US9340848B2 (en) * | 2010-12-20 | 2016-05-17 | Ejot Gmbh And Co. Kg | Screw made of low-alloy carbon steel, and method for producing such a screw |
| CN104227430A (en) * | 2014-09-17 | 2014-12-24 | 平湖市当湖街道飞天人机械图文设计服务部 | Lifting system base of numerical control lathe and thermal treatment technology of lifting system base |
| CN104197127A (en) * | 2014-09-17 | 2014-12-10 | 平湖市当湖街道飞天人机械图文设计服务部 | Connecting bolt of oil circuit of numerical-control lathe and process for thermally treating connecting bolt |
| CN104197128A (en) * | 2014-09-17 | 2014-12-10 | 平湖市当湖街道飞天人机械图文设计服务部 | Bolt of oil circuit of numerical-control lathe and process for thermally treating bolt |
| CN104196851A (en) * | 2014-09-17 | 2014-12-10 | 平湖市当湖街道飞天人机械图文设计服务部 | Automotive body connector and heat treatment process thereof |
| CN104212962A (en) * | 2014-09-17 | 2014-12-17 | 平湖市当湖街道飞天人机械图文设计服务部 | CNC lathe hoisting system connecting element and heat treatment technology of CNC lathe hoisting system connecting element |
| CN104227052A (en) * | 2014-09-17 | 2014-12-24 | 平湖市当湖街道飞天人机械图文设计服务部 | Turning tool outer cover of numerical control lathe and thermal treatment technology of turning tool outer cover |
| CN104191560A (en) * | 2014-09-21 | 2014-12-10 | 金方明 | Injection molding machine base pressing plate and heat processing technology thereof |
| CN104229229A (en) * | 2014-09-21 | 2014-12-24 | 金方明 | Connector for lifting mechanism of packing machine and thermal processing technique thereof |
| CN104212964A (en) * | 2014-09-21 | 2014-12-17 | 金方明 | Injection molding machine pressing plate connecting piece and heat treating process thereof |
| US11331703B2 (en) * | 2015-09-25 | 2022-05-17 | Nippon Steel Corporation | Piercer plug and method of manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10158197A1 (en) | 2003-06-12 |
| WO2003046229A1 (en) | 2003-06-05 |
| DE50210135D1 (en) | 2007-06-21 |
| US20070062620A1 (en) | 2007-03-22 |
| AU2002352053A1 (en) | 2003-06-10 |
| EP1451378A1 (en) | 2004-09-01 |
| ATE361999T1 (en) | 2007-06-15 |
| EP1451378B1 (en) | 2007-05-09 |
| US20060185768A1 (en) | 2006-08-24 |
| ES2286308T3 (en) | 2007-12-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: EJOT VERBINDUNGSTECHNIK GMBH & CO KG, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FRIEDERICH, HEINRICH DR.;SCHMOOCK, REINHARD;REEL/FRAME:015276/0470 Effective date: 20031127 |
|
| AS | Assignment |
Owner name: EJOT GMBH & CO. KG, GERMANY Free format text: MERGER;ASSIGNOR:EJOT VERBINDUNGSTECHNIK GMBH & CO. KG;REEL/FRAME:015015/0626 Effective date: 20040123 |
|
| STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |