CN117488023A - Die steel and heat treatment method thereof - Google Patents
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- CN117488023A CN117488023A CN202311467213.0A CN202311467213A CN117488023A CN 117488023 A CN117488023 A CN 117488023A CN 202311467213 A CN202311467213 A CN 202311467213A CN 117488023 A CN117488023 A CN 117488023A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 240
- 239000010959 steel Substances 0.000 title claims abstract description 240
- 238000010438 heat treatment Methods 0.000 title claims abstract description 104
- 238000000034 method Methods 0.000 title claims abstract description 55
- 238000001816 cooling Methods 0.000 claims abstract description 73
- 238000010791 quenching Methods 0.000 claims abstract description 37
- 230000000171 quenching effect Effects 0.000 claims abstract description 37
- 238000011282 treatment Methods 0.000 claims abstract description 30
- 239000011241 protective layer Substances 0.000 claims abstract description 13
- 238000000137 annealing Methods 0.000 claims abstract description 8
- 239000011248 coating agent Substances 0.000 claims abstract description 4
- 238000000576 coating method Methods 0.000 claims abstract description 4
- 230000008569 process Effects 0.000 claims description 20
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 15
- 229910052799 carbon Inorganic materials 0.000 claims description 15
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 10
- 229910052779 Neodymium Inorganic materials 0.000 claims description 10
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 claims description 10
- 229910052746 lanthanum Inorganic materials 0.000 claims description 10
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 10
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 claims description 10
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 9
- 229910052804 chromium Inorganic materials 0.000 claims description 9
- 239000011651 chromium Substances 0.000 claims description 9
- 229910052710 silicon Inorganic materials 0.000 claims description 9
- 239000010703 silicon Substances 0.000 claims description 9
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 8
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 8
- 229910052748 manganese Inorganic materials 0.000 claims description 8
- 239000011572 manganese Substances 0.000 claims description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims description 8
- 239000011733 molybdenum Substances 0.000 claims description 8
- 229910052759 nickel Inorganic materials 0.000 claims description 8
- 238000005507 spraying Methods 0.000 claims description 8
- 229910052720 vanadium Inorganic materials 0.000 claims description 8
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 8
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 7
- 229910001069 Ti alloy Inorganic materials 0.000 claims description 7
- 229920000642 polymer Polymers 0.000 claims description 7
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 238000004321 preservation Methods 0.000 claims description 6
- 239000004094 surface-active agent Substances 0.000 claims description 6
- 238000009210 therapy by ultrasound Methods 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- 238000010894 electron beam technology Methods 0.000 claims description 4
- 229920002401 polyacrylamide Polymers 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 239000013556 antirust agent Substances 0.000 claims description 3
- 239000002826 coolant Substances 0.000 claims description 3
- 238000007669 thermal treatment Methods 0.000 claims description 3
- 230000007797 corrosion Effects 0.000 abstract description 14
- 238000005260 corrosion Methods 0.000 abstract description 14
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 239000000463 material Substances 0.000 description 15
- 239000000126 substance Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 229910001566 austenite Inorganic materials 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 7
- 229910000734 martensite Inorganic materials 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000005496 tempering Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 150000001247 metal acetylides Chemical class 0.000 description 5
- 239000002202 Polyethylene glycol Substances 0.000 description 4
- 238000005275 alloying Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 229920001223 polyethylene glycol Polymers 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000010410 layer Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229910001562 pearlite Inorganic materials 0.000 description 3
- 229910000162 sodium phosphate Inorganic materials 0.000 description 3
- 239000001488 sodium phosphate Substances 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910001567 cementite Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
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- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000003112 inhibitor Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
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- 239000000047 product Substances 0.000 description 2
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- QIJNJJZPYXGIQM-UHFFFAOYSA-N 1lambda4,2lambda4-dimolybdacyclopropa-1,2,3-triene Chemical compound [Mo]=C=[Mo] QIJNJJZPYXGIQM-UHFFFAOYSA-N 0.000 description 1
- 208000025599 Heat Stress disease Diseases 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910039444 MoC Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- UFGZSIPAQKLCGR-UHFFFAOYSA-N chromium carbide Chemical compound [Cr]#C[Cr]C#[Cr] UFGZSIPAQKLCGR-UHFFFAOYSA-N 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 108010025899 gelatin film Proteins 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical group CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 125000002467 phosphate group Chemical group [H]OP(=O)(O[H])O[*] 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910003470 tongbaite Inorganic materials 0.000 description 1
Classifications
-
- 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
- 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
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/60—Aqueous agents
-
- 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
- C21D1/68—Temporary coatings or embedding materials applied before or during heat treatment
- C21D1/70—Temporary coatings or embedding materials applied before or during heat treatment while heating or quenching
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention discloses a die steel and a heat treatment method thereof, wherein the heat treatment method comprises the following steps: placing the die steel in an annealing furnace, heating to 750-800 ℃, preserving heat for 2-4 hours, and then air-cooling to room temperature; heating the die steel to 720-760 ℃ again, preserving heat for 1-2 h, and then air-cooling to room temperature; heating the die steel to 1050-1150 ℃, and preserving heat for 30-60 min; transferring the die steel into a quenching medium for quenching treatment; heating the quenched die steel to 150-200 ℃, preserving heat for 1-2 h, then air-cooling to room temperature, heating to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature; and coating a protective layer on the surface of the die steel, and performing rapid heat treatment and rapid cold treatment on the die steel, wherein the heating rate of the rapid heat treatment and the cooling rate of the rapid cold treatment are both more than 1000 ℃/s. According to the die steel and the heat treatment method thereof, the microstructure of the die steel can be effectively regulated and controlled through the multi-stage heat treatment strategy, and the thermal fatigue resistance, the corrosion resistance and the tensile property of the die steel are improved.
Description
Technical Field
The invention belongs to the technical field of metal heat treatment, and particularly relates to die steel and a heat treatment method thereof.
Background
In the manufacturing industry, the properties of the die steel are of paramount importance, as it determines the service life of the die, the production efficiency and the quality of the final product. The traditional heat treatment process of the die steel comprises preheating, heating, quenching, tempering and the like, and aims to improve the hardness, wear resistance and fatigue crack resistance of the material. However, as the performance requirements of the manufacturing industry for the mold increase, conventional heat treatment techniques have seen little in many respects.
On the one hand, while conventional heat treatments can enhance the surface hardness of die steel, such enhancement is often at the expense of material internal uniformity and stability. Under long-term or high-strength service conditions, the die steel may suffer thermal fatigue, resulting in the generation of cracks. The formation of such fatigue cracks, particularly under the influence of high temperature repeated loads, can greatly reduce the service life and reliability of the mold.
On the other hand, the conventional heat treatment method has a limitation in improving corrosion resistance. Although corrosion resistance is critical to extending the useful life of the mold and maintaining product quality, conventional methods often fail to effectively provide long-term protection, especially when the mold is subjected to chemical treatments or humid environments.
Accordingly, in view of the above-mentioned problems, it is necessary to provide a new die steel and a heat treatment method thereof.
Disclosure of Invention
The invention aims to provide die steel and a heat treatment method thereof, so as to improve the thermal fatigue resistance and corrosion resistance of the die steel.
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
in a first aspect, the present invention provides a method for heat treatment of die steel, comprising the steps of:
s101: placing the die steel in an annealing furnace, heating to 750-800 ℃, preserving heat for 2-4 hours, cooling to 500 ℃ in a furnace cooling mode, and then cooling to room temperature in an air cooling mode;
s102: heating the die steel to 720-760 ℃ again, preserving heat for 1-2 h, and then air-cooling to room temperature;
s103: heating the die steel to 1050-1150 ℃, and preserving heat for 30-60 min to austenitize the die steel;
s104: transferring the austenitized die steel into a quenching medium for quenching treatment;
s105: heating the quenched die steel to 150-200 ℃, preserving heat for 1-2 h, then air-cooling to room temperature, heating to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature;
s106: and coating a protective layer on the surface of the die steel, and performing rapid heat treatment and rapid cold treatment on the die steel, wherein the heating rate of the rapid heat treatment and the cooling rate of the rapid cold treatment are both more than 1000 ℃/s.
Further, the die steel comprises the following components in percentage by weight:
carbon: 0.35 to 0.45 percent, chromium: 4.5 to 5.5 percent, 1.3 to 1.8 percent of molybdenum, vanadium: 0.8 to 1.2 percent of manganese: 0.2 to 0.4 percent, silicon: 0.8 to 1.2 percent, nickel: 0.3 to 0.8 percent of rare earth elements: 0.02-0.3%, and the balance of iron and unavoidable impurities.
Further, the rare earth elements include at least neodymium, gadolinium, and lanthanum.
Further, in the heat preservation process in S102, the die steel is subjected to ultrasonic treatment, wherein the frequency of the ultrasonic wave is 20-40 kHz, and the amplitude of the ultrasonic wave is 20-100 μm.
Further, the quenching medium comprises a polymer solution, a surfactant and an antirust agent, wherein the polymer solution is a polyvinyl alcohol solution or a polyacrylamide solution.
Further, the step S105 specifically includes:
heating the die steel after quenching treatment to 150-200 ℃, preserving heat for 1-2 h, and then air-cooling to room temperature;
placing the die steel in a freezer, cooling for 4-6 hours at the temperature of-70 ℃ to-100 ℃, and naturally returning to the temperature for 2-4 hours at the room temperature;
and heating the die steel to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature.
Further, a protective layer is coated on the surface of the die steel, and the method specifically comprises the following steps:
spraying titanium or titanium alloy powder with 100-220 meshes on the surface of the die steel at the pressure of 0.2-0.4 MPa, and forming a protective layer on the surface of the die steel.
Further, the rapid thermal processing of the template steel specifically comprises:
scanning the surface of the die steel at a scanning rate of 20-100 mm/s and a scanning overlap rate of 30-50% by using laser or electron beam, and heating the surface of the die steel to 900-1200 ℃.
Further, the rapid cooling treatment is carried out on the template steel, and the method specifically comprises the following steps:
the area of the die steel subjected to the rapid thermal treatment is sprayed with a cooling medium.
In a second aspect, the present invention provides a die steel made by the method as described above.
Compared with the prior art, the die steel and the heat treatment method thereof can effectively regulate and control the microstructure of the die steel through the multi-stage heat treatment strategy, and improve the thermal fatigue resistance, the corrosion resistance and the tensile property of the die steel.
Drawings
Fig. 1 is a flow chart of a method of heat treating die steel in an embodiment of the present application.
Detailed Description
In order to more fully understand the technical content of the present invention, the following description and the description of the technical solution of the present invention will be further presented by specific examples.
It is noted that all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about" unless otherwise indicated. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can be varied appropriately by those skilled in the art utilizing the desired properties sought to be obtained by the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers subsumed within that range and any range within that range, e.g., 1 to 5 includes 1, 1.2, 1.4, 1.55, 2, 2.75, 3, 3.80, 4, 5, and the like.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or article that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article; the term "preferred" refers to a preferred option, but is not limited to the option selected.
In modern manufacturing, the properties of the die steel have a decisive influence on the life of the die, the production efficiency and the quality of the product. With the development of industrial technology and the increase of production requirements, the conventional heat treatment process of die steel faces the challenges of improving hardness and maintaining uniformity of materials, and improvements in terms of improving corrosion resistance and fatigue resistance are also required. In this regard, the limitations of the prior art are that they often fail to address and optimize other performance metrics while improving one performance. Particularly, under the working conditions of high temperature and high pressure, the requirements of thermal fatigue, corrosion resistance and microstructure stability of the die steel are more severe, and a novel heat treatment method capable of comprehensively improving the performance of the die steel is urgently needed.
The technical realization thinking of the invention is based on deep analysis and defect recognition of the existing heat treatment process, and an innovative multi-stage heat treatment strategy is adopted, so that the optimization of the hardness and toughness of the die steel is realized, and the heat fatigue resistance and the corrosion resistance of the die steel are improved. By precisely controlling the temperature and time in the heating and cooling processes, the method of the invention can effectively regulate and control the microstructure of the die steel, thereby obtaining more uniform carbide distribution and finer and uniform martensitic structure. In addition, the invention also particularly considers the environmental factors in the heat treatment process, and further improves the surface performance and the service life of the die steel by applying the surface protection layer and the rapid heat treatment and rapid cooling technology.
Referring to fig. 1, a process flow diagram of a heat treatment method for die steel according to an embodiment of the invention is shown. The heat treatment method of the die steel specifically comprises the following steps:
s101: and (3) placing the die steel in an annealing furnace, heating to 750-800 ℃, preserving heat for 2-4 hours, cooling to 500 ℃ in a furnace cooling mode, and then air-cooling to room temperature.
The die steel is a steel containing a relatively high carbon content and an alloy element, and the structure thereof is mainly composed of pearlite and carbide. Pearlite is a lamellar structure composed of ferrite and cementite, and its hardness and toughness decrease with increasing cementite content. Carbides are a hard phase composed of carbon and alloying elements, which have high hardness and wear resistance, but low toughness. In the manufacturing process of the die steel, internal stress and structural non-uniformity can be generated due to the reasons of processing, cooling, hot rolling and the like, so that the performance of the material is reduced. In addition, the die steel forms austenite at high temperature, which is a ferrite having a face-centered cubic structure, which is capable of dissolving more carbon and alloy elements, and improving the strength and toughness of the material. However, if austenite is not completely transformed into pearlite during cooling, residual austenite remains, the presence of which reduces the stability and toughness of the die steel, increasing the risk of cracking.
Through step S101, the die steel is annealed at a higher temperature to soften the steel, reduce hardness, eliminate internal stress, improve workability, and prepare for a subsequent heat treatment process. At the temperature of 750-800 ℃, carbide particles in the die steel can be redissolved and uniformly distributed, so that the non-uniformity of materials is reduced. In this temperature range, the crystal structure of the steel changes, allowing internal stresses to be relieved, while promoting redistribution of carbon atoms, which contributes to the softening and toughness increase of the material.
In an exemplary embodiment, the die steel comprises the following components in percentage by weight: carbon: 0.35 to 0.45 percent, chromium: 4.5 to 5.5 percent, 1.3 to 1.8 percent of molybdenum, vanadium: 0.8 to 1.2 percent of manganese: 0.2 to 0.4 percent, silicon: 0.80 to 1.2 percent, nickel: 0.3 to 0.8 percent of rare earth elements: 0.02-0.3%, and the balance of iron and unavoidable impurities.
Carbon is a major alloying element of steel, which can increase the strength and hardness of steel, but also reduce the toughness and weldability of steel. The carbon content in the die steel is controlled to be 0.35-0.45%, so that the die steel can be ensured to have enough hardenability and hardenability, and meanwhile, the brittleness increase and carbide precipitation caused by the excessively high carbon content are avoided.
Chromium can improve the wear resistance, corrosion resistance and red hardness of the steel. The chromium content in the die steel is controlled to be 4.5-5.5%, so that the die steel can be ensured to have good wear resistance and heat resistance, and quenching deformation and cracking caused by too high chromium content are avoided.
Molybdenum can improve the strength, toughness and heat resistance of steel. The molybdenum content in the die steel is controlled to be 1.3-1.8%, so that the die steel can be ensured to have high red hardness and thermal fatigue resistance.
Vanadium can improve the strength, hardness and wear resistance of the steel. The vanadium content in the die steel is controlled to be 0.8-1.2%, so that the die steel can be ensured to have fine grains and uniform tissues, and meanwhile, very fine and uniformly distributed carbides can be formed, thereby improving the strength and toughness of the material. These fine carbides are particularly important for resistance to wear, as they provide a hard layer on the material surface, helping to protect the mold from damage.
Manganese can improve the strength, toughness and wear resistance of the steel. The manganese content in the die steel is controlled to be 0.2-0.4%, so that the die steel can be ensured to have proper hardenability and hardenability, and the harmful effect of sulfur can be neutralized, thereby reducing the formation of sulfide in the steel.
Silicon can improve the strength, hardness and wear resistance of the steel. The silicon content in the die steel is controlled to be 0.80-1.2%, so that the die steel can be ensured to have proper hardenability and hardenability, and meanwhile, the brittleness increase of the steel caused by the excessively high silicon content is avoided.
Nickel can improve the strength, toughness and heat resistance of steel. The nickel content in the die steel is controlled to be 0.3-0.8%, so that the die steel can be ensured to have high toughness and thermal fatigue resistance, and the corrosion resistance of the whole die steel is enhanced.
The rare earth element can improve the purity of the steel, refine grains, improve the structure and performance, and improve the hardenability and hardenability of the steel. The rare earth element content in the die steel is controlled to be 0.02-0.3%, so that the die steel can be ensured to have high purity and fine grains.
Preferably, the rare earth elements include at least neodymium, gadolinium and lanthanum. Neodymium is useful for improving the crystallization process of steel and increasing the strength and hardness of materials, and can promote the formation of finer grains of steel during solidification, thereby increasing the strength and toughness of die steel. Gadolinium can reduce the thermal expansion coefficient of steel and improve the dimensional stability of die steel when the temperature is changed. Lanthanum can reduce nonmetallic inclusions in steel, promote grain refinement, and further enhance the strength and toughness of the steel.
S102: and heating the die steel to 720-760 ℃ again, preserving heat for 1-2 h, and then air-cooling to room temperature.
After the annealing treatment in step S101, the internal stress of the die steel is released, the hardness is reduced, and the material becomes softer and more uniform. In order to further improve the performance of the die steel, the secondary heating is performed to perform spheroidization treatment, so that the carbide distribution in the die steel can be optimized. At temperatures ranging from 720 to 760 c, some undissolved carbides will be further dissolved, while the lattice structure of the die steel will allow atomic rearrangement due to the input of thermal energy to reduce microscopic defects and inhomogeneities.
Specifically, in the heat preservation process in S102, the die steel is subjected to ultrasonic treatment, wherein the frequency of the ultrasonic wave is 20-40 kHz, and the amplitude of the ultrasonic wave is 20-100 μm.
The action of the ultrasonic treatment is based on the generation of a microscopic vibration effect inside the material by the ultrasonic energy. These vibrations can affect the atomic and lattice structure in the die steel, thereby improving its performance. Ultrasonic energy may promote grain refinement, resulting in smaller and uniform grain structure formation that improves the strength and toughness of the die steel. The method is favorable for uniform distribution of carbide in steel and reduces carbide segregation. Can promote the floating of inclusions and the escape of gas, thereby reducing the defects in the die steel and improving the purity of the die steel. The conduction efficiency of heat energy in the material can be improved, so that the heat preservation process is more uniform, and the effects of subsequent heat treatment steps such as quenching and tempering are improved.
S103: heating the die steel to 1050-1150 ℃, and preserving heat for 30-60 min to austenitize the die steel.
In the temperature range of 1050 to 1150 ℃, the Body Centered Cubic (BCC) ferrite lattice structure of the die steel is transformed into an austenite structure of the Face Centered Cubic (FCC). This structure more readily dissolves carbon and other alloying elements. The increased solubility of carbon and other alloying elements in austenite at high temperatures promotes uniform distribution of these elements within the material. Carbides (e.g., chromium carbide, molybdenum carbide, etc.) that were otherwise unevenly distributed in the die steel may dissolve into the austenite, helping to form uniform martensite during subsequent quenching.
S104: transferring the austenitized die steel into a quenching medium for quenching treatment.
In step S104, the austenitized die steel is rapidly cooled at a high temperature by the cooling action of the quenching medium, thereby forming a martensitic hard structure, improving the hardness and strength of the die steel, and improving the wear resistance and deformation resistance of the die steel.
Specifically, the quenching medium comprises a polymer solution, a surfactant and an antirust agent, wherein the polymer solution is a polyvinyl alcohol solution or a polyacrylamide solution.
Polyvinyl alcohol and polyacrylamide have a reverse solubility, i.e. are insoluble in water at high temperatures and soluble in water at low temperatures. When the workpiece is quenched into the polymer solution, a steam film and a gel film are formed on the surface of the workpiece, and the two films can enable the workpiece to be slowly cooled in a high temperature area, be quickly cooled in a medium temperature area and be slowly cooled in a low temperature area, so that ideal quenching characteristics are realized.
The surfactant can reduce the surface tension of the solution, so that the quenching medium can wet the surface of the die steel more easily, thereby improving the cooling efficiency and uniformity. During the quenching process, the surfactant can help the solution to expel bubbles, avoiding the formation of bubbles on the die steel surface, which can lead to insufficient local cooling, affecting hardness and microstructure. The surfactant is preferably a stearate of polyethylene glycol, sodium or potassium.
The surface of the die steel is easy to react with oxygen in air in the quenching process to form an oxide layer, so that the subsequent treatment is influenced. The rust inhibitor can form a protective film on the surface of steel, so that oxidation is reduced. The rust inhibitor is preferably a phosphate, nitrate or silicate.
S105: heating the die steel after quenching treatment to 150-200 ℃, preserving heat for 1-2 h, then air-cooling to room temperature, heating to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature.
In step S105, the brittleness of the die steel after quenching can be significantly reduced by two-stage tempering treatment, and brittle fracture during use can be prevented. In the low-temperature tempering stage (150-200 ℃), the residual stress formed in the quenching process can be reduced, so that the occurrence of cracks after quenching is prevented. Martensite in the steel does not undergo a significant structural change in the temperature range of 150-200 c, but releases a portion of the internal stress. In the intermediate temperature tempering stage (550-650 ℃), martensite starts to decompose and carbide starts to precipitate, so that the hardness of the die steel is reduced, and the toughness and the plasticity are improved.
In an exemplary embodiment, step S105 specifically includes: heating the die steel after quenching treatment to 150-200 ℃, preserving heat for 1-2 h, and then air-cooling to room temperature; placing the die steel in a freezer, cooling for 4-6 hours at the temperature of-70 ℃ to-100 ℃, and naturally returning to the temperature for 2-4 hours at the room temperature; and heating the die steel to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature.
After the low-temperature tempering treatment is carried out on the die steel, the low-temperature sub-cooling treatment (-70 ℃ to-100 ℃) is carried out, and the residual austenite in the die steel can be converted into martensite, so that the hardness and the stability of the material are improved.
S106: and coating a protective layer on the surface of the die steel, and performing rapid heat treatment and rapid cold treatment on the die steel, wherein the heating rate of the rapid heat treatment and the cooling rate of the rapid cold treatment are both more than 1000 ℃/s.
Specifically, titanium or titanium alloy powder with the granularity of 100-220 meshes is sprayed on the surface of the die steel at the pressure of 0.2-0.4 MPa, and a protective layer is formed on the surface of the die steel; using a laser or an electron beam; scanning the surface of the die steel at a scanning rate of 20-100 mm/s and a scanning overlapping rate of 30-50%, and heating the surface of the die steel to 900-1200 ℃ (rapid heat treatment); the region of the die steel subjected to the rapid thermal treatment is sprayed (rapid cooling treatment) using a cooling medium.
The protective layer formed of titanium or titanium alloy powder can prevent oxidation, corrosion and carbon loss of the die steel during rapid heat treatment and cold treatment to enhance the durability and impact resistance of the die steel surface. By laser or electron beam rapid heating, fine austenite grains can be formed on the surface of the mold steel, which grains are transformed into martensite in a subsequent rapid cooling process, thereby locally changing the microstructure of the surface layer of the mold steel to improve hardness and wear resistance while maintaining the internal properties of the steel, thereby achieving differentiation of the structure and properties of the surface layer and core of the mold steel. The surface layer of the die steel has high hardness, strength, wear resistance and fatigue resistance, is suitable for working conditions such as high pressure, high speed, high temperature and the like, and the core of the die steel has high toughness and plasticity, and is suitable for working conditions such as impact, vibration, deformation and the like.
In one embodiment of the invention, a die steel is provided, which is made by the method.
The invention will be further illustrated with reference to specific examples.
Example 1
Chemical composition of die steel: carbon: 0.4%, chromium: 5%, molybdenum 1.5%, vanadium: 1%, manganese: 0.3%, silicon: 1%, nickel: 0.5 percent of rare earth elements (the mass ratio of neodymium, gadolinium and lanthanum is 1:1:1): 0.09%, the balance being iron and unavoidable impurities.
And (3) placing the die steel in an annealing furnace, heating to 780 ℃, preserving heat for 3 hours, cooling to 500 ℃ in a furnace cooling mode, and then air-cooling to room temperature. And heating the die steel to 740 ℃, preserving heat for 2 hours, then air-cooling to room temperature, and carrying out ultrasonic treatment on the die steel in the heat preservation process, wherein the frequency of ultrasonic waves is 30kHz, and the amplitude of the ultrasonic waves is 50 mu m.
And heating the die steel to 1100 ℃, and preserving heat for 40min to austenitize the die steel. The austenitized die steel was then rapidly transferred to a quenching medium (90% polyvinyl alcohol solution at 10% strength, 6% polyethylene glycol, 4% sodium phosphate) for quenching.
And heating the die steel subjected to quenching treatment to 160 ℃, preserving heat for 2 hours, and then air-cooling to room temperature. The die steel is placed in a freezer, cooled for 5 hours at the temperature of minus 80 ℃, and naturally warmed for 3 hours at the room temperature. Heating to 600 deg.c, maintaining for 3 hr, and air cooling to room temperature.
And spraying titanium alloy powder with the granularity of 200 meshes on the surface of the die steel under the pressure of 0.3MPa, and forming a protective layer on the surface of the die steel. The surface of the die steel was scanned using a laser at a scan rate of 50mm/s, a scan overlap rate of 30%, and heated to 1100 ℃ (heating rate greater than 1000 ℃/s). And then spraying and cooling the laser scanned area on the die steel by using liquid nitrogen (the cooling rate is more than 1000 ℃/s) until the whole die steel surface is covered.
Example 2
The die steel had neodymium as the entire rare earth element in the chemical composition compared with example 1, and the other conditions were the same as in example 1.
Example 3
The die steel had gadolinium as the rare earth element in the chemical composition compared with example 1, and the other conditions were the same as in example 1.
Example 4
The die steel had all lanthanum as the rare earth element in the chemical composition compared with example 1, and the other conditions were the same as in example 1.
Example 5
The die steel had a chemical composition of neodymium and lanthanum in a mass ratio of 1:1 as compared with example 1, except that the other conditions were the same as in example 1.
Example 6
The die steel had a chemical composition of neodymium and gadolinium in a mass ratio of 1:1 as compared with example 1, except that the other conditions were the same as in example 1.
Example 7
The die steel had a chemical composition of lanthanum and gadolinium in a mass ratio of 1:1 as compared with example 1, except that the conditions were the same as in example 1.
Example 8
The quenching medium was water as compared with example 1, and the other conditions were the same as in example 1.
Example 9
Chemical composition of die steel: carbon: 0.4%, chromium: 5%, molybdenum 1.5%, vanadium: 1%, manganese: 0.3%, silicon: 1%, nickel: 0.5 percent of rare earth elements (the mass ratio of neodymium, gadolinium and lanthanum is 1:1:1): 0.09%, the balance being iron and unavoidable impurities.
And (3) placing the die steel in an annealing furnace, heating to 780 ℃, preserving heat for 3 hours, cooling to 500 ℃ in a furnace cooling mode, and then air-cooling to room temperature. And heating the die steel to 740 ℃ again, preserving heat for 2 hours, and then cooling to room temperature in air.
And heating the die steel to 1100 ℃, and preserving heat for 40min to austenitize the die steel. The austenitized die steel was then rapidly transferred to a quenching medium (90% polyvinyl alcohol solution at 10% strength, 6% polyethylene glycol, 4% sodium phosphate) for quenching.
And heating the die steel subjected to quenching treatment to 160 ℃, preserving heat for 2 hours, and then air-cooling to room temperature. The die steel is placed in a freezer, cooled for 5 hours at the temperature of minus 80 ℃, and naturally warmed for 3 hours at the room temperature. Heating to 600 deg.c, maintaining for 3 hr, and air cooling to room temperature.
And spraying titanium alloy powder with the granularity of 200 meshes on the surface of the die steel under the pressure of 0.3MPa, and forming a protective layer on the surface of the die steel. The surface of the die steel was scanned using a laser at a scan rate of 50mm/s, a scan overlap rate of 30%, and heated to 1100 ℃ (heating rate greater than 1000 ℃/s). And then spraying and cooling the laser scanned area on the die steel by using liquid nitrogen (the cooling rate is more than 1000 ℃/s) until the whole die steel surface is covered.
Example 10
Chemical composition of die steel: carbon: 0.4%, chromium: 5%, molybdenum 1.5%, vanadium: 1%, manganese: 0.3%, silicon: 1%, nickel: 0.5 percent of rare earth elements (the mass ratio of neodymium, gadolinium and lanthanum is 1:1:1): 0.09%, the balance being iron and unavoidable impurities.
And (3) placing the die steel in an annealing furnace, heating to 780 ℃, preserving heat for 3 hours, cooling to 500 ℃ in a furnace cooling mode, and then air-cooling to room temperature. And heating the die steel to 740 ℃, preserving heat for 2 hours, then air-cooling to room temperature, and carrying out ultrasonic treatment on the die steel in the heat preservation process, wherein the frequency of ultrasonic waves is 30kHz, and the amplitude of the ultrasonic waves is 50 mu m.
And heating the die steel to 1100 ℃, and preserving heat for 40min to austenitize the die steel. The austenitized die steel was then rapidly transferred to a quenching medium (90% polyvinyl alcohol solution at 10% strength, 6% polyethylene glycol, 4% sodium phosphate) for quenching.
And heating the die steel subjected to quenching treatment to 160 ℃, preserving heat for 2 hours, and then air-cooling to room temperature. Heating to 600 deg.c, maintaining for 3 hr, and air cooling to room temperature.
And spraying titanium alloy powder with the granularity of 200 meshes on the surface of the die steel under the pressure of 0.3MPa, and forming a protective layer on the surface of the die steel. The surface of the die steel was scanned using a laser at a scan rate of 50mm/s, a scan overlap rate of 30%, and heated to 1100 ℃ (heating rate greater than 1000 ℃/s). And then spraying and cooling the laser scanned area on the die steel by using liquid nitrogen (the cooling rate is more than 1000 ℃/s) until the whole die steel surface is covered.
Performance testing
Corrosion resistance: the corrosion resistance of the die steel was tested according to standard ASTM B117.
Tensile properties: the test method of mechanical properties of high-temperature stretching at 700 ℃ is referred to GB/T4338-2006.
Thermal fatigue resistance: the surface of the die steel is polished smooth, the microstructure and defects of the die steel are observed by a metallographic microscope, a proper position is selected, and a small hole is drilled on the surface of the die as a starting point of a crack. Mounting die steel on a clamp of a thermal fatigue testing machine, and adjusting the position and angle of the clamp to enable the axis of the die steel to be parallel to the axis of the clamp and enable the position of a small hole to be aligned with the center of the clamp; setting test parameters, wherein the load amplitude is 200MPa, the load frequency is 3Hz, the temperature amplitude is 1000 ℃, the temperature frequency is 0.05Hz, and the cycle number is 5 multiplied by 10 5 Secondly, starting the testing machine according to a specified program, and starting to apply cyclic load and temperature change; at intervals of each cycle number, the tester is stopped, the length of the crack is measured with a microscope or other instrument, data is recorded, and the test is continued until the die steel breaks or a predetermined number of cycles is reached.
In summary, the die steel and the heat treatment method thereof provided by the invention can effectively regulate and control the microstructure of the die steel and improve the thermal fatigue resistance, corrosion resistance and tensile property of the die steel through a multi-stage heat treatment strategy.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment contains only one independent technical solution, and that such description is provided for clarity only, and that the technical solutions of the embodiments may be appropriately combined to form other embodiments that will be understood by those skilled in the art.
Claims (10)
1. A method for heat treatment of die steel, comprising the steps of:
s101: placing the die steel in an annealing furnace, heating to 750-800 ℃, preserving heat for 2-4 hours, cooling to 500 ℃ in a furnace cooling mode, and then cooling to room temperature in an air cooling mode;
s102: heating the die steel to 720-760 ℃ again, preserving heat for 1-2 h, and then air-cooling to room temperature;
s103: heating the die steel to 1050-1150 ℃, and preserving heat for 30-60 min to austenitize the die steel;
s104: transferring the austenitized die steel into a quenching medium for quenching treatment;
s105: heating the quenched die steel to 150-200 ℃, preserving heat for 1-2 h, then air-cooling to room temperature, heating to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature;
s106: and coating a protective layer on the surface of the die steel, and performing rapid heat treatment and rapid cold treatment on the die steel, wherein the heating rate of the rapid heat treatment and the cooling rate of the rapid cold treatment are both more than 1000 ℃/s.
2. The method of heat treatment of die steel according to claim 1, wherein the die steel comprises the following components in weight percent:
carbon: 0.35 to 0.45 percent, chromium: 4.5 to 5.5 percent, 1.3 to 1.8 percent of molybdenum, vanadium: 0.8 to 1.2 percent of manganese: 0.2 to 0.4 percent, silicon: 0.8 to 1.2 percent, nickel: 0.3 to 0.8 percent of rare earth elements: 0.02-0.3%, and the balance of iron and unavoidable impurities.
3. A die steel heat treatment method according to claim 2, wherein the rare earth elements include at least neodymium, gadolinium and lanthanum.
4. The heat treatment method of die steel according to claim 1, wherein the die steel is subjected to ultrasonic treatment in the heat preservation process in S102, the ultrasonic wave having a frequency of 20 to 40kHz and an amplitude of 20 to 100 μm.
5. The method of heat treatment of die steel according to claim 1, wherein the quenching medium comprises a polymer solution, a surfactant and an antirust agent, and the polymer solution is a polyvinyl alcohol solution or a polyacrylamide solution.
6. The heat treatment method for die steel according to claim 1, wherein S105 specifically comprises:
heating the die steel after quenching treatment to 150-200 ℃, preserving heat for 1-2 h, and then air-cooling to room temperature;
placing the die steel in a freezer, cooling for 4-6 hours at the temperature of-70 ℃ to-100 ℃, and naturally returning to the temperature for 2-4 hours at the room temperature;
and heating the die steel to 550-650 ℃, preserving heat for 2-4 h, and then air-cooling to room temperature.
7. The heat treatment method of die steel according to claim 1, wherein a protective layer is coated on the surface of the die steel, specifically comprising:
spraying titanium or titanium alloy powder with 100-220 meshes on the surface of the die steel at the pressure of 0.2-0.4 MPa, and forming a protective layer on the surface of the die steel.
8. The method for heat treatment of die steel according to claim 1, characterized in that the die steel is subjected to rapid heat treatment, specifically comprising:
scanning the surface of the die steel at a scanning rate of 20-100 mm/s and a scanning overlap rate of 30-50% by using laser or electron beam, and heating the surface of the die steel to 900-1200 ℃.
9. The method for heat treatment of die steel according to claim 1, characterized in that the die steel is subjected to rapid cooling treatment, specifically comprising:
the area of the die steel subjected to the rapid thermal treatment is sprayed with a cooling medium.
10. A die steel, characterized in that it is produced by the method according to any one of claims 1 to 9.
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