US20030094218A1 - Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products - Google Patents
Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products Download PDFInfo
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- US20030094218A1 US20030094218A1 US10/325,730 US32573002A US2003094218A1 US 20030094218 A1 US20030094218 A1 US 20030094218A1 US 32573002 A US32573002 A US 32573002A US 2003094218 A1 US2003094218 A1 US 2003094218A1
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 87
- 239000010959 steel Substances 0.000 title claims abstract description 87
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 51
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 17
- 238000001556 precipitation Methods 0.000 title description 4
- 230000009466 transformation Effects 0.000 claims abstract description 28
- 238000000137 annealing Methods 0.000 claims abstract description 21
- 238000010791 quenching Methods 0.000 claims abstract description 11
- 230000000171 quenching effect Effects 0.000 claims abstract description 11
- 238000004881 precipitation hardening Methods 0.000 claims abstract description 7
- 238000007493 shaping process Methods 0.000 claims abstract description 6
- 239000002245 particle Substances 0.000 claims abstract description 4
- 230000001235 sensitizing effect Effects 0.000 claims description 11
- 239000011651 chromium Substances 0.000 claims description 9
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 4
- 239000012530 fluid Substances 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims description 2
- 239000000047 product Substances 0.000 description 24
- 239000000463 material Substances 0.000 description 12
- 239000010936 titanium Substances 0.000 description 9
- 229910001566 austenite Inorganic materials 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 229910052719 titanium Inorganic materials 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 229910052750 molybdenum Inorganic materials 0.000 description 5
- 238000005098 hot rolling Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000005275 alloying Methods 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 2
- 230000001687 destabilization Effects 0.000 description 2
- 229910000765 intermetallic Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000000930 thermomechanical effect Effects 0.000 description 2
- 229910001240 Maraging steel Inorganic materials 0.000 description 1
- 229910000943 NiAl Inorganic materials 0.000 description 1
- 206010070834 Sensitisation Diseases 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
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- 238000000227 grinding Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 235000000396 iron Nutrition 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 238000005482 strain hardening Methods 0.000 description 1
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Images
Classifications
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- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/02—Hardening by precipitation
-
- 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
- C21D1/26—Methods of annealing
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
-
- 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
- C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
-
- 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
- C21D9/18—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for knives, scythes, scissors, or like hand cutting tools
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/04—Hardening by cooling below 0 degrees Celsius
Definitions
- the present invention relates to a method for the manufacture of a steel product wherein the steel is subjected to isothermal martensite formation and precipitation hardening in a martensitic structure subsequent to soft annealing and shaping.
- the invention also relates to a steel product obtained with such method and to the use of said steel product.
- One aspect of the present invention is a method for the manufacture of a steel product comprising the steps of subjecting the steel to precipitation hardening in a martensitic structure subsequent to soft annealing.
- the steel is then shaped into the desired form followed by solution annealing between a temperature of 1200° C. and 1050° C. and for a time period of from 5 to 30 minutes. From the annealing temperature, the steel is quenched at a rate of at least 5° C. per second to a temperature below 500° C. The quenched steel being subjected to an isothermal martensitic transformation. Hardening of the steel is then accomplished at a temperature of between 450° C. and 550° C. for at least 3 minutes to cause precipitation of particles out of solution into the martensitic structure.
- FIG. 1 is a temperature profile in time of the heat treatment and processing method of the present invention.
- a method for the manufacture of a steel product according to the invention is characterized by shaping of the steel followed by solution annealing between 1200° C. and 1050° C. for from 5 to 30 minutes, after which the steel is quenched from the solution annealing temperature to a temperature below 500° C. with a quenching speed of at least 5° C. per second.
- the quenched steel is then subjected to an isothermal martensitic transformation and is subsequently hardened by being held at a temperature between 450° C. and 550° C. for at least 3 minutes to precipitate out particles from solution into the martensitic structure.
- a method for the manufacture of steel products according to the invention is further characterized by subjecting the quenched steel to an isothermal martensitic transformation by holding the steel at a temperature between ⁇ 30° C. and ⁇ 50° C. for at least one hour.
- a method for the manufacture of steel products according to the invention is still further characterized by a sensitizing procedure in which the steel is held at a temperature between 950° C. and 850° C. for at least 5 minutes so as to allow initiation of the martensitic transformation to become optimal.
- the sensitizing procedure occurs between solution annealing and quenching the steel.
- a steel subjected to a sensitizing procedure avoids thermo-mechanical stresses which would otherwise build up internally in the steel product. The absence of internal thermo-mechanical stresses enables the manufacture of a steel product with a very accurate size and which is stable in use.
- a further object of the invention is to provide a method of manufacture of a steel product exhibiting a combination of superior strength, corrosion resistance and ductility.
- Such a method is further characterized in that the steel comprises chromium (Cr) in a weight percentage between 10% and 14%.
- Cr chromium
- martensitic steels with a low weight percentage of carbon so-called maraging steels, may be with or without chromium.
- Corrosion resistant maraging steels comprise a weight percentage of chromium between 10.5 and 18%.
- a particular type of maraging steel which may be obtained by the method according to the invention, contains in weight percentage 10-14% Cr, 7-10% Ni, 5-6% Mo, 0-9% Co, 0.5-4% Cu, 0.05-0.5% Al, 0.4-1.4% Ti and less than 0.03% C and N.
- a steel material suitable for use with the present invention and containing a weight percentage of Cr of 10-14% was produced as a strip material from a full scale seven ton melt in a high frequency furnace and then subjected to rolling.
- the solidification process after melting 1 is shown in FIG. 1 in which the temperature profile over time is indicated by a solid line. Solidification of the melt leads to crystallization of Ti (C, N), thereby binding the free carbon and free nitrogen. The binding of free nitrogen is important because the free nitrogen would otherwise prohibit the isothermal martensitic transformation.
- the steel Before rolling, the steel is reheated to a temperature of 1150-1250° C. and soaked at this temperature for at least 1 hour in order to give the material an austenitic structure and sufficient ductility to be hot rolled. Reheating to a temperature of 1150-1250° C. 2 is followed by hot rolling 3 .
- Hot rolling 3 produces a material in a strip shape with a suitable grain size and evenly distributed intermetallic inclusions of carbon. Additionally, hot rolling into a strip is accomplished without resulting in a strain induced martensitic transformation.
- Scale oxide layers formed during soaking and hot rolling has to be removed by etching and/or grinding before the material can be cold rolled to final dimensions.
- Cold rolling 4 gives the strip steel the final thickness without formation of oxide layers.
- Cold rolling 4 leads to strain induced martensitic transformations and, to ensure sufficient ductility to form a complicated product, the material has to be brought back into the austenitic condition by annealing 5 .
- This annealing 5 is carried out in a continuous furnace at a temperature around 1050° C., to prevent the material from transforming to martensite before shaping of the product.
- the product is cold formed in the austenitic condition 6 leading to a partial transformation to strain induced martensite.
- the material has to be solution annealed 7 for 5 to 30 minutes at a temperature between 1050° C. and 1200° C.
- Solution annealing 7 also causes Al, Mo, Cu, Ti, C and N to go into substitutional and/or interstitial solution in the austenitic structure and reversion of strain induced martensite to austenite.
- the elements Al, Cu, Mo and Ti in solution are used for precipitation hardening of the isothermal martensite in a later stage of the manufacture.
- the martensitic transformation 10 should be carried out at a temperature between ⁇ 30° C. and ⁇ 50° C. for at least one hour. More preferably, the isothermal martensitic transformation 10 is preceded by a sensitizing process 8 .
- the sensitizing process 8 is positioned between a solution annealing step 7 and a quenching step 9 .
- the sensitizing process 8 occurs when the steel is held at a temperature between 850° C. and 950° C. for at least five minutes.
- the sensitizing process 8 causes destabilization of the austenitic structure of the steel material and so facilitates the later isothermal martensitic transformation 10 .
- the steel material is subjected to an isothermal martensitic transformation 10 .
- This transformation is accomplished by holding the steel at a temperature of ⁇ 30° C. to ⁇ 50° C. for at least one hour.
- the result is a homogeneous martensitic structure with regularly distributed retained austenite in a fine grain size.
- the isothermal martensitic transformation 10 is followed by a hardening procedure 11 during which intermetallic compounds like ⁇ -Ni 3 (Al, Mo, Ti) and ⁇ -NiAl precipitate out from substitutional and/or interstitial solution into the martensitic structure.
- the steel product so treated will have a homogeneous hardness of more than 500 HV.
- a steel product which is obtained by the present method exhibits excellent properties with respect to wear and corrosion resistance, homogeneous hardness and ductility during the austenitic phase of the manufacture. This makes the strip steel product very attractive for shaver caps of electric rotary shavers, which are subjected to deep drawing during manufacture in order to obtain the necessary bowl shape. The same applies to the heavily deformed cutters of shavers, the strongly shaped knives of blenders and the strongly folded return springs for thermostats in irons.
- the chemical composition in weight percentages of a steel material which is very well suited to be subjected to the treatment method according to the present invention is as follows (so-called Sandvik 1RK91 steel): C + N ⁇ 0.05 Cr 12.00 Mn 0.30 Fe balance Ni 9.00 Mo 4.00 Ti 0.90 Al 0.30 Si 0.15 Cu 2.00
- a steel material or product with the same chemical composition as in Example 1 may be produced as a diaphragm plate spring functioning as a return spring in a fluid valve.
- it may be allowed to have so-called rest austenite in the product after quenching 9 .
- Diaphragm plate springs for many applications use complicated shapes which require strong deformations during forming. Such deformations cause strain induced martensite which has to be reversed into austenite by solution annealing 7 .
- the method of the present invention is well suited to preparing the steel stock for this application.
Abstract
Description
- 1. Field of the Invention
- The present invention relates to a method for the manufacture of a steel product wherein the steel is subjected to isothermal martensite formation and precipitation hardening in a martensitic structure subsequent to soft annealing and shaping. The invention also relates to a steel product obtained with such method and to the use of said steel product.
- 2. State of the Art
- In the discussion of the state of the art that follows, reference is made to certain structures and/or methods. However, the following references should not necessarily be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention.
- In published international patent application WO93/07303, a method of manufacture of the above mentioned kind has been described wherein the transformation into the martensitic structure is accomplished by air cooling after annealing in the austenitic region or by cold working. Air cooling after annealing normally results in the so-called athermal kinetic mode of martensite transformation. The formation of air cooling induced martensite is suppressed by alloying elements like nickel, titanium and aluminum, which are used for precipitation of hardenable steel. It may be that at relatively high concentrations of such alloying elements the austenite is stabilized such that the martensitic transformation start temperature becomes impracticably low.
- It is an object of the invention to offer a method for the manufacture of steel products, steel products so manufactured and the use of said steel products whereby a practical optimum is achieved between ductility, strength, wear and corrosion resistance, homogeneity of martensite distribution and a practical level of the martensite transformation temperature.
- One aspect of the present invention is a method for the manufacture of a steel product comprising the steps of subjecting the steel to precipitation hardening in a martensitic structure subsequent to soft annealing. The steel is then shaped into the desired form followed by solution annealing between a temperature of 1200° C. and 1050° C. and for a time period of from 5 to 30 minutes. From the annealing temperature, the steel is quenched at a rate of at least 5° C. per second to a temperature below 500° C. The quenched steel being subjected to an isothermal martensitic transformation. Hardening of the steel is then accomplished at a temperature of between 450° C. and 550° C. for at least 3 minutes to cause precipitation of particles out of solution into the martensitic structure.
- The objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments thereof in connection with the accompanying drawing.
- FIG. 1 is a temperature profile in time of the heat treatment and processing method of the present invention.
- A method for the manufacture of a steel product according to the invention is characterized by shaping of the steel followed by solution annealing between 1200° C. and 1050° C. for from 5 to 30 minutes, after which the steel is quenched from the solution annealing temperature to a temperature below 500° C. with a quenching speed of at least 5° C. per second. The quenched steel is then subjected to an isothermal martensitic transformation and is subsequently hardened by being held at a temperature between 450° C. and 550° C. for at least 3 minutes to precipitate out particles from solution into the martensitic structure.
- A combination of an isothermal martensitic transformation and precipitation hardening is known (See Scripta Metallurgica et Materialia, 1995, Vol. 33, No. 9, pp. 1367-1373). However, a method of manufacture of the above-mentioned kind which allows a steel product to be formed of a relatively complicated shape by deformation whilst achieving an optimum between ductility, strength, wear and corrosion resistance and homogeneity of martensite distribution is not disclosed.
- It is a further object of the invention to provide a very efficient method for the manufacture of steel products with a homogeneous distribution of martensite and precipitates.
- Accordingly, a method for the manufacture of steel products according to the invention is further characterized by subjecting the quenched steel to an isothermal martensitic transformation by holding the steel at a temperature between −30° C. and −50° C. for at least one hour.
- A method for the manufacture of steel products according to the invention is still further characterized by a sensitizing procedure in which the steel is held at a temperature between 950° C. and 850° C. for at least 5 minutes so as to allow initiation of the martensitic transformation to become optimal. The sensitizing procedure occurs between solution annealing and quenching the steel. A steel subjected to a sensitizing procedure avoids thermo-mechanical stresses which would otherwise build up internally in the steel product. The absence of internal thermo-mechanical stresses enables the manufacture of a steel product with a very accurate size and which is stable in use.
- A further object of the invention is to provide a method of manufacture of a steel product exhibiting a combination of superior strength, corrosion resistance and ductility. Such a method is further characterized in that the steel comprises chromium (Cr) in a weight percentage between 10% and 14%. Generally, martensitic steels with a low weight percentage of carbon, so-called maraging steels, may be with or without chromium. Corrosion resistant maraging steels comprise a weight percentage of chromium between 10.5 and 18%. A particular type of maraging steel, which may be obtained by the method according to the invention, contains in weight percentage 10-14% Cr, 7-10% Ni, 5-6% Mo, 0-9% Co, 0.5-4% Cu, 0.05-0.5% Al, 0.4-1.4% Ti and less than 0.03% C and N.
- The invention will be elucidated further by the use of practical examples:
- A steel material suitable for use with the present invention and containing a weight percentage of Cr of 10-14% was produced as a strip material from a full scale seven ton melt in a high frequency furnace and then subjected to rolling. The solidification process after melting1 is shown in FIG. 1 in which the temperature profile over time is indicated by a solid line. Solidification of the melt leads to crystallization of Ti (C, N), thereby binding the free carbon and free nitrogen. The binding of free nitrogen is important because the free nitrogen would otherwise prohibit the isothermal martensitic transformation.
- Before rolling, the steel is reheated to a temperature of 1150-1250° C. and soaked at this temperature for at least 1 hour in order to give the material an austenitic structure and sufficient ductility to be hot rolled. Reheating to a temperature of 1150-1250° C.2 is followed by hot rolling 3. Hot rolling 3 produces a material in a strip shape with a suitable grain size and evenly distributed intermetallic inclusions of carbon. Additionally, hot rolling into a strip is accomplished without resulting in a strain induced martensitic transformation.
- Scale (oxide layers) formed during soaking and hot rolling has to be removed by etching and/or grinding before the material can be cold rolled to final dimensions. Cold rolling4 gives the strip steel the final thickness without formation of oxide layers. Cold rolling 4, however, leads to strain induced martensitic transformations and, to ensure sufficient ductility to form a complicated product, the material has to be brought back into the austenitic condition by annealing 5. This annealing 5 is carried out in a continuous furnace at a temperature around 1050° C., to prevent the material from transforming to martensite before shaping of the product. The product is cold formed in the
austenitic condition 6 leading to a partial transformation to strain induced martensite. To ensure a homogeneous martensite transformation throughout the product and sufficient hardenability of the formed martensite by precipitation hardening, the material has to be solution annealed 7 for 5 to 30 minutes at a temperature between 1050° C. and 1200° C. Solution annealing 7 also causes Al, Mo, Cu, Ti, C and N to go into substitutional and/or interstitial solution in the austenitic structure and reversion of strain induced martensite to austenite. The elements Al, Cu, Mo and Ti in solution are used for precipitation hardening of the isothermal martensite in a later stage of the manufacture. - In order to achieve an optimal isothermal
martensitic transformation 10, themartensitic transformation 10 should be carried out at a temperature between −30° C. and −50° C. for at least one hour. More preferably, the isothermalmartensitic transformation 10 is preceded by asensitizing process 8. Thesensitizing process 8 is positioned between a solution annealingstep 7 and aquenching step 9. Thesensitizing process 8 occurs when the steel is held at a temperature between 850° C. and 950° C. for at least five minutes. Thesensitizing process 8 causes destabilization of the austenitic structure of the steel material and so facilitates the later isothermalmartensitic transformation 10. It has been determined that during thesensitizing process 8, Mo and Ti are removed from the solution and it is believed that Mo concentrates along crystal boundaries. The behavior of Ti is not yet clear. Sensitization further ensures homogeneous nucleation of martensite during the isothermalmartensitic transformation 10. Quenching 9 to room temperature or even lower prevents premature precipitation of essential intermetallic compounds in the austenite. - After quenching9, the steel material is subjected to an isothermal
martensitic transformation 10. This transformation is accomplished by holding the steel at a temperature of −30° C. to −50° C. for at least one hour. The result is a homogeneous martensitic structure with regularly distributed retained austenite in a fine grain size. The isothermalmartensitic transformation 10 is followed by a hardening procedure 11 during which intermetallic compounds like η-Ni3(Al, Mo, Ti) and β-NiAl precipitate out from substitutional and/or interstitial solution into the martensitic structure. The steel product so treated will have a homogeneous hardness of more than 500 HV. - A steel product which is obtained by the present method exhibits excellent properties with respect to wear and corrosion resistance, homogeneous hardness and ductility during the austenitic phase of the manufacture. This makes the strip steel product very attractive for shaver caps of electric rotary shavers, which are subjected to deep drawing during manufacture in order to obtain the necessary bowl shape. The same applies to the heavily deformed cutters of shavers, the strongly shaped knives of blenders and the strongly folded return springs for thermostats in irons.
- The chemical composition in weight percentages of a steel material, which is very well suited to be subjected to the treatment method according to the present invention is as follows (so-called Sandvik 1RK91 steel):
C + N <0.05 Cr 12.00 Mn 0.30 Fe balance Ni 9.00 Mo 4.00 Ti 0.90 Al 0.30 Si 0.15 Cu 2.00 - A steel material or product with the same chemical composition as in Example 1 may be produced as a diaphragm plate spring functioning as a return spring in a fluid valve. Depending on the required accuracy of the diaphragm plate spring dimensions, it may be allowed to have so-called rest austenite in the product after quenching9. In the event that maximum accuracy is required, it is preferred to anneal the
solution 7 followed by sensitizing thesolution 8 which causes destabilization of the austenite so that the later isothermalmartensitic transformation 10 is facilitated. Diaphragm plate springs for many applications use complicated shapes which require strong deformations during forming. Such deformations cause strain induced martensite which has to be reversed into austenite bysolution annealing 7. The method of the present invention is well suited to preparing the steel stock for this application. - Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims.
Claims (16)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US10/325,730 US20030094218A1 (en) | 1999-08-23 | 2002-12-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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SE9902977-9 | 1999-08-23 | ||
SE9902977A SE520169C2 (en) | 1999-08-23 | 1999-08-23 | Method for the manufacture of steel products of precipitated hardened martensitic steel, and the use of these steel products |
US09/644,079 US6531007B1 (en) | 1999-08-23 | 2000-08-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
US10/325,730 US20030094218A1 (en) | 1999-08-23 | 2002-12-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US09/644,079 Division US6531007B1 (en) | 1999-08-23 | 2000-08-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
Publications (1)
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US20030094218A1 true US20030094218A1 (en) | 2003-05-22 |
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US09/644,079 Expired - Lifetime US6531007B1 (en) | 1999-08-23 | 2000-08-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
US10/325,730 Abandoned US20030094218A1 (en) | 1999-08-23 | 2002-12-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
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US09/644,079 Expired - Lifetime US6531007B1 (en) | 1999-08-23 | 2000-08-23 | Method for the manufacture of steel products of a precipitation hardened martensitic steel, steel products obtained with such method and use of said steel products |
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US (2) | US6531007B1 (en) |
EP (1) | EP1216311B1 (en) |
JP (1) | JP5099865B2 (en) |
KR (1) | KR100767834B1 (en) |
CN (1) | CN1140640C (en) |
AT (1) | ATE292194T1 (en) |
DE (1) | DE60019141T2 (en) |
HK (1) | HK1049863A1 (en) |
SE (1) | SE520169C2 (en) |
WO (1) | WO2001014601A1 (en) |
Cited By (5)
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US20050241159A1 (en) * | 2002-08-02 | 2005-11-03 | Koninkilijke Phillips Electronics N.V. | Wear-resistant stainless cutting element of an electric shaver, electric shaver, and method of producing such a cutting element |
WO2006114499A2 (en) * | 2005-04-27 | 2006-11-02 | Aubert & Duval | Tempered martensitic steel, method of producing a part from said steel and part thus obtained |
WO2009007562A1 (en) * | 2007-07-10 | 2009-01-15 | Aubert & Duval | Hardened martensitic steel having a low or zero content of cobalt, process for manufacturing a part from this steel, and part thus obtained |
CN110241380A (en) * | 2019-06-02 | 2019-09-17 | 邢晓英 | A kind for the treatment of process of medical free nickel stainless steel |
RU2740294C1 (en) * | 2020-10-16 | 2021-01-12 | федеральное государственное бюджетное образовательное учреждение высшего образования "Нижегородский государственный технический университет им. Р.Е. Алексеева" (НГТУ) | Method of martensite-aging steel hardening treatment |
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- 2000-08-23 DE DE60019141T patent/DE60019141T2/en not_active Expired - Lifetime
- 2000-08-23 KR KR1020027002263A patent/KR100767834B1/en not_active IP Right Cessation
- 2000-08-23 JP JP2001518468A patent/JP5099865B2/en not_active Expired - Lifetime
- 2000-08-23 WO PCT/SE2000/001634 patent/WO2001014601A1/en active IP Right Grant
- 2000-08-23 AT AT00957215T patent/ATE292194T1/en not_active IP Right Cessation
- 2000-08-23 EP EP00957215A patent/EP1216311B1/en not_active Expired - Lifetime
- 2000-08-23 US US09/644,079 patent/US6531007B1/en not_active Expired - Lifetime
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Publication number | Priority date | Publication date | Assignee | Title |
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US20050241159A1 (en) * | 2002-08-02 | 2005-11-03 | Koninkilijke Phillips Electronics N.V. | Wear-resistant stainless cutting element of an electric shaver, electric shaver, and method of producing such a cutting element |
US8152938B2 (en) | 2005-04-27 | 2012-04-10 | Aubert & Duval | Hardened martensitic steel, method for producing a component from this steel and component obtained in this manner |
US8192560B2 (en) | 2005-04-27 | 2012-06-05 | Aubert & Duval | Hardened martensitic steel, method for producing a component from this steel and component obtained in this manner |
WO2006114499A3 (en) * | 2005-04-27 | 2006-12-14 | Aubert & Duval Sa | Tempered martensitic steel, method of producing a part from said steel and part thus obtained |
US20080193321A1 (en) * | 2005-04-27 | 2008-08-14 | Aubert & Duval | Hardened Martensitic Steel, Method For Producing A Component From This Steel And Component Obtained In This Manner |
FR2885142A1 (en) * | 2005-04-27 | 2006-11-03 | Aubert & Duval Soc Par Actions | CURED MARTENSITIC STEEL, METHOD FOR MANUFACTURING A WORKPIECE THEREFROM, AND PIECE THUS OBTAINED |
US8153056B2 (en) | 2005-04-27 | 2012-04-10 | Aubert & Duval | Hardened martensitic steel, method for producing a component from this steel and component obtained in this manner |
US20110041961A1 (en) * | 2005-04-27 | 2011-02-24 | Aubert & Duval | Hardened martensitic steel, method for producing a component from this steel and component obtained in this manner |
US20110048583A1 (en) * | 2005-04-27 | 2011-03-03 | Aubert & Duval | Hardened martensitic steel, method for producing a component from this steel and component obtained in this manner |
WO2006114499A2 (en) * | 2005-04-27 | 2006-11-02 | Aubert & Duval | Tempered martensitic steel, method of producing a part from said steel and part thus obtained |
US20100200119A1 (en) * | 2007-07-10 | 2010-08-12 | Aubert & Duval | Hardened martensitic steel having a low or zero content of cobalt, method for producing a component from this steel, and component obtained in this manner |
WO2009007562A1 (en) * | 2007-07-10 | 2009-01-15 | Aubert & Duval | Hardened martensitic steel having a low or zero content of cobalt, process for manufacturing a part from this steel, and part thus obtained |
US9045806B2 (en) | 2007-07-10 | 2015-06-02 | Aubert & Duval | Hardened martensitic steel having a low or zero content of cobalt, method for producing a component from this steel, and component obtained in this manner |
CN110241380A (en) * | 2019-06-02 | 2019-09-17 | 邢晓英 | A kind for the treatment of process of medical free nickel stainless steel |
RU2740294C1 (en) * | 2020-10-16 | 2021-01-12 | федеральное государственное бюджетное образовательное учреждение высшего образования "Нижегородский государственный технический университет им. Р.Е. Алексеева" (НГТУ) | Method of martensite-aging steel hardening treatment |
Also Published As
Publication number | Publication date |
---|---|
CN1370243A (en) | 2002-09-18 |
SE9902977D0 (en) | 1999-08-23 |
CN1140640C (en) | 2004-03-03 |
WO2001014601A1 (en) | 2001-03-01 |
DE60019141D1 (en) | 2005-05-04 |
KR100767834B1 (en) | 2007-10-17 |
HK1049863A1 (en) | 2003-05-30 |
US6531007B1 (en) | 2003-03-11 |
ATE292194T1 (en) | 2005-04-15 |
JP2003507576A (en) | 2003-02-25 |
SE520169C2 (en) | 2003-06-03 |
KR20020042648A (en) | 2002-06-05 |
EP1216311A1 (en) | 2002-06-26 |
JP5099865B2 (en) | 2012-12-19 |
EP1216311B1 (en) | 2005-03-30 |
DE60019141T2 (en) | 2005-08-11 |
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