CN114990292B - Heat treatment method for hot work die steel - Google Patents
Heat treatment method for hot work die steel Download PDFInfo
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- CN114990292B CN114990292B CN202111386557.XA CN202111386557A CN114990292B CN 114990292 B CN114990292 B CN 114990292B CN 202111386557 A CN202111386557 A CN 202111386557A CN 114990292 B CN114990292 B CN 114990292B
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 115
- 239000010959 steel Substances 0.000 title claims abstract description 115
- 238000010438 heat treatment Methods 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000001816 cooling Methods 0.000 claims abstract description 89
- 238000010791 quenching Methods 0.000 claims abstract description 54
- 230000000171 quenching effect Effects 0.000 claims abstract description 54
- 238000005496 tempering Methods 0.000 claims abstract description 50
- 238000005255 carburizing Methods 0.000 claims abstract description 16
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 8
- 238000000137 annealing Methods 0.000 claims abstract description 7
- 238000007689 inspection Methods 0.000 claims abstract description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 238000001514 detection method Methods 0.000 claims description 11
- 230000000630 rising effect Effects 0.000 claims description 11
- 230000002950 deficient Effects 0.000 claims description 5
- 239000012467 final product Substances 0.000 claims description 5
- 230000006698 induction Effects 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 238000011084 recovery Methods 0.000 claims description 5
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- 229910052720 vanadium Inorganic materials 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 238000012360 testing method Methods 0.000 claims description 4
- 238000004321 preservation Methods 0.000 claims description 3
- 239000011651 chromium Substances 0.000 abstract description 7
- 230000008569 process Effects 0.000 abstract description 7
- 229910000734 martensite Inorganic materials 0.000 abstract description 5
- 229910001566 austenite Inorganic materials 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 abstract description 3
- 230000008646 thermal stress Effects 0.000 abstract description 3
- 238000001125 extrusion Methods 0.000 abstract description 2
- 230000001131 transforming effect Effects 0.000 abstract description 2
- 239000010410 layer Substances 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000012935 Averaging Methods 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 238000001192 hot extrusion Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical compound OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 229910001315 Tool steel Inorganic materials 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000005256 carbonitriding Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000004512 die casting Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229910000859 α-Fe 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
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
- C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
-
- 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
- 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
- C22C38/02—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
- 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
- C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
-
- 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
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
- C23C8/22—Carburising of ferrous surfaces
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses a heat treatment method for hot working die steel, and particularly relates to the field of hot working dies, which comprises S1), annealing, S2), quenching, S3), high-temperature tempering, S4), carburizing and S5) and quality inspection. The invention can lead the internal thermal stress to be more uniformly diffused through the first-order and second-order preheating and heating treatment, lead the die steel to be cooled more fully and stably through multi-order cooling after quenching, reduce the deformation, simultaneously coordinate with primary tempering and secondary tempering, lead the die steel to be capable of decomposing martensite and transforming residual austenite at higher temperature, lead carbide to keep larger dispersivity, thereby improving the resistance and thermal fatigue resistance of tempering softening on the premise of meeting the central hardness in the subsequent use process of the die steel, and effectively avoiding the phenomenon of secondary hardening caused by chromium elements in the die steel at 500 ℃ during the primary and secondary stage tempering, being beneficial to ensuring the toughness of the die steel and further leading the die steel to be more rapidly conductive under high-temperature extrusion.
Description
Technical Field
The invention relates to the technical field of hot working dies, in particular to a heat treatment method for hot working die steel.
Background
The hot working die steel is an alloy tool steel suitable for manufacturing a die for performing heat deformation processing on metal, such as a hot forging die, a hot extrusion die, a die casting die, a hot upsetting die and the like, and since the hot working die is operated under high temperature and high pressure conditions for a long time, the die material is required to have high strength, hardness and thermal stability, particularly high thermal strength, thermal fatigue, toughness and wear resistance, and the heat treatment is a metal hot working process in which the material is in a solid state through heating, heat preservation and cooling means to obtain the expected structure and performance, and the effect of the heat treatment is gradually known in the process of advancing from the stone age to the copper age and the iron age.
In the manufacturing process of the die, heat treatment is generally adopted to obtain the processed die steel, so that the die steel has certain metal properties, but for a part of hot working plastic die, the traditional die steel is poor in wear resistance and thermal fatigue resistance in the use process, so that the die steel cannot well meet the use requirement of the hot extrusion of the plastic die, and therefore, the heat treatment method for the hot working die steel is provided.
Disclosure of Invention
In order to overcome the above-mentioned drawbacks of the prior art, an embodiment of the present invention provides a heat treatment method for hot work die steel, which aims to solve the technical problems: the wear resistance and the thermal fatigue resistance of the die steel are improved, so that the die steel can better meet the hot working plastic die application.
In order to achieve the above purpose, the present invention provides the following technical solutions: a heat treatment method for hot work die steel, which consists of the following components in percentage by weight: 0.250 to 0.30 percent of C, 1.50 to 1.70 percent of Mn, 0.70 to 1.20 percent of Si, 1.60 to 2.00 percent of W, 0.10 to 0.20 percent of Mo, 1.60 to 1.80 percent of V, 1.20 to 1.50 percent of Ni, 4.50 to 5.10 percent of Cr, 0.2 to 0.6 percent of Co, less than or equal to 0.010 percent of S, less than or equal to 0.03 percent of P and the balance of Fe;
the heat treatment method of the hot work die steel comprises the following steps:
s1), annealing:
s11), heating the workpiece to 850-880 ℃, and keeping the temperature for 2-4 hours;
s12), air cooling to enable the temperature in the furnace to be reduced to 500+/-10 ℃;
s2), quenching:
s21), one-stage preheating: the temperature rising rate is 1-5 ℃/min, and the temperature rises to 550+/-10 ℃;
s22), two-stage preheating: the temperature rising rate is 5-12 ℃/min, and the temperature rises to 850+/-10 ℃;
s23), high temperature cooling: the final temperature in the step S22) is cooled to 600 ℃, and the cooling speed is 5-12 ℃/min;
and (3) medium-temperature cooling: cooling from 600 ℃ to 450 ℃ at a cooling speed of 5-8 ℃/min;
and (3) low-temperature cooling: cooling from 450 ℃ to 250 ℃ at a cooling speed of 3-5 ℃/min;
s3), high-temperature tempering:
s31), primary tempering: charging the steel into a furnace after quenching at the temperature of less than or equal to 250 ℃, and heating to maintain the temperature in the furnace at 550-650 ℃ for 2-3 h;
and (3) secondary tempering: charging the furnace after the temperature is less than or equal to 650 ℃, and heating to keep the temperature in the furnace at 520-620 ℃ and the heat preservation time at 2-2.5 h;
s32), cooling the die steel subjected to the secondary tempering in the step;
s4), carburizing:
s41), placing the die steel cooled to room temperature in the step S32) in an active carburizing medium, heating to 900-950 ℃, and preserving heat for 30-40 h;
s42), surface quenching: carrying out surface quenching on the die steel in the step S41) through a double-frequency quenching inductor;
s43), low temperature tempering: charging the quenching furnace after the quenching temperature is less than or equal to 150 ℃, heating to keep the temperature in the furnace at 150-250 ℃ and keeping the temperature for 2-3 h;
s44), taking out the cold area of the die steel to room temperature, and finishing the heat treatment of the hot work die steel;
s5), quality inspection.
In a preferred embodiment, the cooling method in step S23) is any one of oil cooling, air cooling, and water cooling.
In a preferred embodiment, the cooling method in step S32) is oil cooling and cooling to room temperature.
In a preferred embodiment, the carbon content in the hot work die steel is between 0.25 and 0.3%.
In a preferred embodiment, the frequency of the dual-frequency quenching inductor in the step S42) is 200hz to 300hz, the height of the induction coil is 70 cm to 120cm, and the quenching temperature is 1000 ℃ to 1250 ℃.
In a preferred embodiment, the step S5) includes the steps of:
s51): detecting a carbon layer of the carburized die steel by a thickness detection instrument, wherein the thickness of the carbon layer is more than or equal to 0.9 and is qualified;
s52): the hardness test was averaged over three different locations of the die steel surface by a hardness test tool.
In a preferred embodiment, the step S5) further comprises the steps of:
s53): carrying out metallographic examination on the die steel through a two-dimensional metallographic specimen mill;
s54): the qualified die steel in steps S51), S52) and S53) is the final product, and one or more steps are not qualified, and the defective area is returned to wait for recovery.
The invention has the technical effects and advantages that:
1. the invention can lead the internal thermal stress to be more uniformly diffused through the first-order and second-order preheating and heating treatment, and lead the die steel to be cooled more fully and stably through multi-order cooling after quenching, reduce the deformation, simultaneously match with primary tempering and secondary tempering, lead the die steel to be capable of decomposing martensite and transforming residual austenite at a higher temperature, lead carbide to keep larger dispersivity, thereby improving the resistance and thermal fatigue resistance of tempering softening on the premise of meeting the central hardness in the subsequent use process of the die steel, and effectively avoiding the phenomenon of secondary hardening caused by chromium elements in the die steel at 500 ℃ during the primary and secondary tempering, being beneficial to ensuring the toughness of the die steel, further leading the die steel to be faster in heat conduction under high-temperature extrusion and further improving the comprehensive mechanical property.
2. According to the invention, through further carburizing treatment on the quenched and tempered die steel, activated carbon atoms decomposed in a carburized medium permeate into the surface layer of the steel piece, so that the lower surface of the die steel still has good hardness and wear resistance on the premise of enhancing the central hardness of the die steel, and the conditions of cracking, deformation and the like of the die steel are not easy to occur due to stable use of the die steel under the conditions of long-time hot extrusion and high die cavity heating temperature are ensured.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1:
the invention provides a heat treatment method for hot work die steel, which comprises the following components in percentage by weight: 0.250 to 0.30 percent of C, 1.50 to 1.70 percent of Mn, 0.70 to 1.20 percent of Si, 1.60 to 2.00 percent of W, 0.10 to 0.20 percent of Mo, 1.60 to 1.80 percent of V, 1.20 to 1.50 percent of Ni, 4.50 to 5.10 percent of Cr, 0.2 to 0.6 percent of Co, less than or equal to 0.010 percent of S, less than or equal to 0.03 percent of P and the balance of Fe;
the heat treatment method of the hot work die steel comprises the following steps;
s1), annealing:
s11), heating the workpiece to 850 ℃ and keeping the temperature for 2-4 hours;
s12), air cooling to enable the temperature in the furnace to be reduced to 500+/-10 ℃;
s2), quenching:
s21), one-stage preheating: the temperature rising rate is 1-5 ℃/min, and the temperature rises to 550+/-10 ℃;
s22), two-stage preheating: the temperature rising rate is 5-12 ℃/min, and the temperature rises to 850+/-10 ℃;
the first-order second-order preheating temperature rising treatment ensures that the internal thermal stress can be more uniformly diffused, and the die steel is cooled more fully and stably by multi-order cooling after quenching, so that the deformation is reduced;
s23), high temperature cooling: the final temperature in the step S22) is cooled to 600 ℃, and the cooling speed is 5-12 ℃/min;
the cooling method in the step S23) is any one of oil cooling, air cooling and water cooling;
and (3) medium-temperature cooling: cooling from 600 ℃ to 450 ℃ at a cooling speed of 5-8 ℃/min;
and (3) low-temperature cooling: cooling from 450 ℃ to 250 ℃ at a cooling speed of 3-5 ℃/min;
s3), high-temperature tempering:
s31), primary tempering: charging the quenching furnace after the quenching temperature is less than or equal to 250 ℃, and heating to maintain the temperature in the furnace at 550 ℃ for 2-3 h;
and (3) secondary tempering: charging the furnace after the temperature is less than or equal to 650 ℃, and heating to keep the temperature in the furnace at 520 ℃ for 2-2.5 h;
the primary tempering and the secondary tempering enable the die steel to be subjected to martensite decomposition and retained austenite transformation at a higher temperature, so that carbide keeps larger dispersity, thereby improving the resistance to tempering softening and thermal fatigue resistance on the premise of meeting the central hardness in the subsequent use process of the die steel, and the primary tempering and the secondary tempering effectively avoid the phenomenon of secondary hardening caused by chromium elements in the die steel in 500 ℃, and are beneficial to ensuring the toughness of the die steel;
s32), cooling the die steel subjected to the secondary tempering in the step;
the alloy elements in the hot work die steel delay the decomposition of martensite and the transformation of residual austenite in the primary tempering and secondary tempering processes, the recrystallization temperature of ferrite is improved, and carbide is difficult to gather and grow and keeps larger dispersity, so that the resistance of the steel to tempering softening is improved, namely the tempering stability of the steel is improved;
the cooling method in the step S32) is oil cooling, and the cooling is carried out to room temperature;
step S2) quenching and step S3) high-temperature tempering are carried out to finish the quenching and tempering of the hot work die steel, and the hot work die steel is subjected to quenching and tempering treatment to obtain high toughness and strength and good comprehensive mechanical properties;
s4), carburizing:
s41), placing the die steel cooled to room temperature in the step S32) in an active carburizing medium, heating to 900 ℃, and preserving heat for 30-40 h;
s42), surface quenching: carrying out surface quenching on the die steel in the step S41) through a double-frequency quenching inductor;
the frequency of the double-frequency quenching inductor in the step S42) is 200hz to 300hz, the height of the induction coil is 70 cm to 120cm, and the quenching temperature is 1000 ℃ to 1250 ℃;
the surface of the workpiece generates compressive internal stress through quenching after carburization, which is beneficial to improving the fatigue strength of the workpiece;
s43), low temperature tempering: charging the quenching furnace after the quenching temperature is less than or equal to 150 ℃, heating to keep the temperature in the furnace at 150-250 ℃ and keeping the temperature for 2-3 h;
the low-temperature tempering is favorable for the secondary decomposition of martensite to form sorbite, and good mechanical properties can be obtained;
s44), taking out the cold area of the die steel to room temperature, and finishing the heat treatment of the hot work die steel;
the carburization can be divided into gas carburization, solid carburization, liquid carburization and carbonitriding, and the gas carburization is adopted in the step S4), namely, hot work die steel is filled into a closed carburizing furnace, one of a gas carburizing agent (methane, ethane and the like) or a liquid carburizing agent (kerosene, benzene, alcohol and acetone) is introduced, active carbon atoms are decomposed at high temperature, and the active carbon atoms penetrate into the surface of a workpiece, so that the hot work die steel with good hardness and wear resistance is obtained;
s5), quality inspection;
step S5) comprises the steps of:
s51): detecting a carbon layer of the carburized die steel by a thickness detection instrument, wherein the thickness of the carbon layer is more than or equal to 0.9 and is qualified;
s52): performing hardness detection and averaging on three different positions of the surface of the die steel by using a hardness detection tool;
s53): the method comprises the steps of carrying out metallographic examination on die steel through a two-dimensional metallographic specimen mill, wherein the metallographic examination mainly adopts a quantitative metallographic principle, and uses measurement and calculation of a metallographic microstructure of a two-dimensional metallographic specimen mill face or a film to determine the three-dimensional space morphology of an alloy structure, so as to establish a quantitative relation among alloy components, structures and performances, and assist a worker to carry out further measurement treatment on hot work die steel;
s54): the qualified die steel in steps S51), S52) and S53) is the final product, and one or more steps are not qualified, and the defective area is returned to wait for recovery.
Example 2:
the invention provides a heat treatment method for hot work die steel, which comprises the following components in percentage by weight: 0.250 to 0.30 percent of C, 1.50 to 1.70 percent of Mn, 0.70 to 1.20 percent of Si, 1.60 to 2.00 percent of W, 0.10 to 0.20 percent of Mo, 1.60 to 1.80 percent of V, 1.20 to 1.50 percent of Ni, 4.50 to 5.10 percent of Cr, 0.2 to 0.6 percent of Co, less than or equal to 0.010 percent of S, less than or equal to 0.03 percent of P and the balance of Fe;
the heat treatment method of the hot work die steel comprises the following steps;
s1), annealing:
s11), heating the workpiece to 865 ℃ and keeping the temperature for 2-4 hours;
s12), air cooling to enable the temperature in the furnace to be reduced to 500+/-10 ℃;
s2), quenching:
s21), one-stage preheating: the temperature rising rate is 1-5 ℃/min, and the temperature rises to 550+/-10 ℃;
s22), two-stage preheating: the temperature rising rate is 5-12 ℃/min, and the temperature rises to 850+/-10 ℃;
s23), high temperature cooling: the final temperature in the step S22) is cooled to 600 ℃, and the cooling speed is 5-12 ℃/min;
the cooling method in the step S23) is any one of oil cooling, air cooling and water cooling;
and (3) medium-temperature cooling: cooling from 600 ℃ to 450 ℃ at a cooling speed of 5-8 ℃/min;
and (3) low-temperature cooling: cooling from 450 ℃ to 250 ℃ at a cooling speed of 3-5 ℃/min;
s3), high-temperature tempering:
s31), primary tempering: charging the steel into a furnace after quenching at the temperature of less than or equal to 250 ℃, and heating to maintain the temperature in the furnace at 600 ℃ for 2-3 h;
and (3) secondary tempering: charging the furnace after the temperature is less than or equal to 650 ℃, and heating to keep the temperature in the furnace at 580 ℃ for 2-2.5 h;
s32), cooling the die steel subjected to the secondary tempering in the step;
the cooling method in the step S32) is oil cooling, and the cooling is carried out to room temperature;
s4), carburizing:
s41), placing the die steel cooled to room temperature in the step S32) in an active carburizing medium, heating to 930 ℃, and preserving heat for 30-40 h;
s42), surface quenching: carrying out surface quenching on the die steel in the step S41) through a double-frequency quenching inductor;
the frequency of the double-frequency quenching inductor in the step S42) is 200hz to 300hz, the height of the induction coil is 70 cm to 120cm, and the quenching temperature is 1000 ℃ to 1250 ℃;
s43), low temperature tempering: charging the quenching furnace after the quenching temperature is less than or equal to 150 ℃, heating to keep the temperature in the furnace at 150-250 ℃ and keeping the temperature for 2-3 h;
s44), taking out the cold area of the die steel to room temperature, and finishing the heat treatment of the hot work die steel;
s5), quality inspection;
step S5) comprises the steps of:
s51): detecting a carbon layer of the carburized die steel by a thickness detection instrument, wherein the thickness of the carbon layer is more than or equal to 0.9 and is qualified;
s52): performing hardness detection and averaging on three different positions of the surface of the die steel by using a hardness detection tool;
s53): carrying out metallographic examination on the die steel through a two-dimensional metallographic specimen mill;
s54): the qualified die steel in steps S51), S52) and S53) is the final product, and one or more steps are not qualified, and the defective area is returned to wait for recovery.
Example 3:
the invention provides a heat treatment method for hot work die steel, which comprises the following components in percentage by weight: 0.250 to 0.30 percent of C, 1.50 to 1.70 percent of Mn, 0.70 to 1.20 percent of Si, 1.60 to 2.00 percent of W, 0.10 to 0.20 percent of Mo, 1.60 to 1.80 percent of V, 1.20 to 1.50 percent of Ni, 4.50 to 5.10 percent of Cr, 0.2 to 0.6 percent of Co, less than or equal to 0.010 percent of S, less than or equal to 0.03 percent of P and the balance of Fe;
the heat treatment method of the hot work die steel comprises the following steps;
s1), annealing:
s11), heating the workpiece to 880 ℃, and keeping the temperature for 2-4 hours;
s12), air cooling to enable the temperature in the furnace to be reduced to 500+/-10 ℃;
s2), quenching:
s21), one-stage preheating: the temperature rising rate is 1-5 ℃/min, and the temperature rises to 550+/-10 ℃;
s22), two-stage preheating: the temperature rising rate is 5-12 ℃/min, and the temperature rises to 850+/-10 ℃;
s23), high temperature cooling: the final temperature in the step S22) is cooled to 600 ℃, and the cooling speed is 5-12 ℃/min;
the cooling method in the step S23) is any one of oil cooling, air cooling and water cooling;
and (3) medium-temperature cooling: cooling from 600 ℃ to 450 ℃ at a cooling speed of 5-8 ℃/min;
and (3) low-temperature cooling: cooling from 450 ℃ to 250 ℃ at a cooling speed of 3-5 ℃/min;
s3), high-temperature tempering:
s31), primary tempering: charging the steel into a furnace after quenching at the temperature of less than or equal to 250 ℃, and heating to maintain the temperature in the furnace at 650 ℃ for 2-3 h;
and (3) secondary tempering: charging the furnace after the temperature is less than or equal to 650 ℃, and heating to keep the temperature in the furnace at 620 ℃ and keeping the temperature for 2-2.5 h;
s32), cooling the die steel subjected to the secondary tempering in the step;
the cooling method in the step S32) is oil cooling, and the cooling is carried out to room temperature;
s4), carburizing:
s41), placing the die steel cooled to room temperature in the step S32) in an active carburizing medium, heating to 950 ℃, and preserving heat for 30-40 h;
s42), surface quenching: carrying out surface quenching on the die steel in the step S41) through a double-frequency quenching inductor;
the frequency of the double-frequency quenching inductor in the step S42) is 200hz to 300hz, the height of the induction coil is 70 cm to 120cm, and the quenching temperature is 1000 ℃ to 1250 ℃;
s43), low temperature tempering: charging the quenching furnace after the quenching temperature is less than or equal to 150 ℃, heating to keep the temperature in the furnace at 150-250 ℃ and keeping the temperature for 2-3 h;
s44), taking out the cold area of the die steel to room temperature, and finishing the heat treatment of the hot work die steel;
s5), quality inspection;
step S5) comprises the steps of:
s51): detecting a carbon layer of the carburized die steel by a thickness detection instrument, wherein the thickness of the carbon layer is more than or equal to 0.9 and is qualified;
s52): performing hardness detection and averaging on three different positions of the surface of the die steel by using a hardness detection tool;
s53): carrying out metallographic examination on the die steel through a two-dimensional metallographic specimen mill;
s54): the qualified die steel in steps S51), S52) and S53) is the final product, and one or more steps are not qualified, and the defective area is returned to wait for recovery.
Example 4:
the hot work die steels prepared in examples 1 to 3 above were respectively taken for measurement of red hardness, impact toughness, thermal conductivity and tensile strength properties, five pieces of work pieces were taken in each example, and an average value of the measurement coefficients of the hot work die steels in five pieces of each example was taken to obtain the following data:
as is clear from the above table, in example 2, the annealing temperature (865 ℃), the primary tempering (600 ℃), the secondary tempering (580 ℃) and the carburizing temperature (930 ℃) are all in the optimal boundary values, and the steel has better resistance to tempering and softening, thermal fatigue resistance, heat conduction performance, hardness and wear resistance, and the comprehensive mechanical property is greatly improved compared with the traditional hot work die steel after the steel is measured.
Finally: while the techniques of the present invention have been described in terms of preferred embodiments, it will be apparent to those skilled in the art that variations and rearrangements of the techniques described herein can be made to achieve the final manufacturing techniques without departing from the spirit, scope, and spirit of the invention, and it is intended that all such similar alterations and modifications be apparent to those skilled in the art from this disclosure be considered to be included within the spirit, scope, and content of the invention.
Claims (6)
1. A heat treatment method for hot work die steel, characterized by comprising the steps of: the hot work die steel comprises the following components in percentage by weight: 0.250 to 0.30 percent of C, 1.50 to 1.70 percent of Mn, 0.70 to 1.20 percent of Si, 1.60 to 2.00 percent of W, 0.10 to 0.20 percent of Mo, 1.60 to 1.80 percent of V, 1.20 to 1.50 percent of Ni, 4.50 to 5.10 percent of Cr, 0.2 to 0.6 percent of Co, less than or equal to 0.010 percent of S, less than or equal to 0.03 percent of P and the balance of Fe;
the heat treatment method of the hot work die steel comprises the following steps:
s1), annealing:
s11), heating the workpiece to 850-880 ℃, and keeping the temperature for 2-4 hours;
s12), air cooling to enable the temperature in the furnace to be reduced to 500+/-10 ℃;
s2), quenching:
s21), one-stage preheating: the temperature rising rate is 1-5 ℃/min, and the temperature rises to 550+/-10 ℃;
s22), two-stage preheating: the temperature rising rate is 5-12 ℃/min, and the temperature rises to 850+/-10 ℃;
s23), high temperature cooling: the final temperature in the step S22) is cooled to 600 ℃, and the cooling speed is 5-12 ℃/min;
and (3) medium-temperature cooling: cooling from 600 ℃ to 450 ℃ at a cooling speed of 5-8 ℃/min;
and (3) low-temperature cooling: cooling from 450 ℃ to 250 ℃ at a cooling speed of 3-5 ℃/min;
s3), high-temperature tempering:
s31), primary tempering: charging the steel into a furnace after quenching at the temperature of less than or equal to 250 ℃, and heating to maintain the temperature in the furnace at 550-650 ℃ for 2-3 h;
and (3) secondary tempering: charging the furnace after the temperature is less than or equal to 650 ℃, and heating to keep the temperature in the furnace at 520-620 ℃ and the heat preservation time at 2-2.5 h;
s32), cooling the die steel subjected to the secondary tempering in the step;
s4), carburizing:
s41), placing the die steel cooled to room temperature in the step S32) in an active carburizing medium, heating to 900-950 ℃, and preserving heat for 30-40 h;
s42), surface quenching: carrying out surface quenching on the die steel in the step S41) through a double-frequency quenching inductor;
s43), low temperature tempering: charging the quenching furnace after the quenching temperature is less than or equal to 150 ℃, heating to keep the temperature in the furnace at 150-250 ℃ and keeping the temperature for 2-3 h;
s44), taking out the cold area of the die steel to room temperature, and finishing the heat treatment of the hot work die steel;
s5), quality inspection.
2. A heat treatment method for hot work die steel according to claim 1, characterized in that: the cooling method in step S23) is any one of oil cooling, air cooling and water cooling.
3. A heat treatment method for hot work die steel according to claim 1, characterized in that: the cooling method in step S32) is oil cooling, and cooling to room temperature.
4. A heat treatment method for hot work die steel according to claim 1, characterized in that: the frequency of the double-frequency quenching inductor in the step S42) is 200hz to 300hz, the height of the induction coil is 70 cm to 120cm, and the quenching temperature is 1000 ℃ to 1250 ℃.
5. A heat treatment method for hot work die steel according to claim 1, characterized in that: said step S5) comprises the steps of:
s51): detecting a carbon layer of the carburized die steel by a thickness detection instrument, wherein the thickness of the carbon layer is more than or equal to 0.9 and is qualified;
s52): the hardness test was averaged over three different locations of the die steel surface by a hardness test tool.
6. A heat treatment method for hot work die steel as claimed in claim 5, wherein: the step S5) further comprises the steps of:
s53): carrying out metallographic examination on the die steel through a two-dimensional metallographic specimen mill;
s54): the qualified die steel in steps S51), S52) and S53) is the final product, and one or more steps are not qualified, and the defective area is returned to wait for recovery.
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