CN113881831B - Post-forging heat treatment method for Cr-Mo-V medium carbon medium alloy steel - Google Patents
Post-forging heat treatment method for Cr-Mo-V medium carbon medium alloy steel Download PDFInfo
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- CN113881831B CN113881831B CN202111171966.8A CN202111171966A CN113881831B CN 113881831 B CN113881831 B CN 113881831B CN 202111171966 A CN202111171966 A CN 202111171966A CN 113881831 B CN113881831 B CN 113881831B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
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- 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
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- 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
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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- 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
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
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- 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 after forging of Cr-Mo-V medium carbon alloy steel, wherein a forging piece is cooled to 700-760 ℃ along with a furnace for primary annealing to obtain an equilibrium state structure; heating to 1010-1040 ℃ again, preserving heat, austenitizing and re-nucleation; adopting water-air alternative rapid cooling to reduce the surface temperature of the forging to below 450 ℃ for heat preservation; heating to A c1 Preserving heat at the temperature of between 30 and 50 ℃ and fusing and spheroidizing the unmelted strip carbide; cooling to the pearlite transformation zone to be isothermal, and discharging and air cooling along with furnace cooling to below 500 ℃. The invention adopts the process mode of repeated phase change recrystallization equilibrium annealing after forging, low-temperature air alternate cooling quenching and spheroidizing annealing, effectively eliminates the inheritance of the original coarse structure, and successfully solves the problems of uneven structure, coarse grains and unstable mechanical property of the Cr-Mo-V medium carbon alloy steel.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a heat treatment method after forging of Cr-Mo-V medium carbon medium alloy steel.
Background
The Cr-Mo-V medium carbon alloy steel is a medium alloy steel with high strength and toughness, has high temperature strength, good toughness and cold and hot fatigue resistance, has wide application range, and is mainly used for manufacturing forging dies, hot extrusion dies, precision forging dies, various alloy die-casting dies and the like with large impact load, and the steel types of the medium alloy steel comprise 4Cr5MoSiV (H11), DIEVAR, 4Cr5MoSiV1 (H13), 8418 and the like.
As the steel belongs to hypereutectoid steel, the austenite stability is strong, the heat sensitivity is high, the conventional spheroidizing annealing treatment is adopted after forging, and the heat treatment method often has the phenomena of uneven structure, coarse grains and the like, and influences the comprehensive mechanical property and the service life of products.
Disclosure of Invention
The invention aims to provide a post-forging heat treatment method suitable for Cr-Mo-V medium carbon alloy steel, which adopts a process mode of repeated phase change recrystallization equilibrium annealing after forging, low-temperature water air alternate cooling quenching and spheroidizing annealing to effectively eliminate the inheritance of original coarse tissues and successfully solve the problems of uneven tissue, coarse grains and unstable mechanical property of the Cr-Mo-V medium carbon alloy steel.
In order to achieve the above purpose, the technical solution adopted by the invention is as follows:
the after-forging heat treatment method of Cr-Mo-V medium carbon alloy steel comprises the following steps: cooling the forging to 700-760 ℃ along with the furnace for primary annealing to obtain an equilibrium state structure; heating to 1010-1040 deg.c, maintaining the temperature, austenitizing and re-nucleation; adopting water-air alternative rapid cooling to reduce the surface temperature of the forging to below 450 ℃ for heat preservation; heating to A c1 Preserving heat at the temperature of between 30 and 50 ℃ and fusing and spheroidizing the unmelted strip carbide; cooling to the pearlite transformation zone to be isothermal, and discharging and air cooling along with furnace cooling to below 500 ℃.
Further, immediately feeding the steel ingot into a furnace after forging and forming, waiting for material at the temperature of more than or equal to 850 ℃, and quickly heating to 1010-1040 ℃ after material alignment, and preserving heat for 10-15 hours; then cooling to 700-760 ℃ along with the furnace, preserving heat for 15-20 hours, wherein the cooling rate is less than or equal to 30 ℃/h; heating to 1010-1040 ℃ again, preserving heat for 10-15 hours, and fully dissolving the net carbide precipitated in the forging process to eliminate the original coarse grains; adopting water-air alternative rapid cooling to reduce the surface temperature of the forging to below 450 ℃, and preserving heat for 6-10 hours in a low-temperature furnace at 300-350 ℃; heating to 840-880 ℃, preserving heat for 15-20 hours, cooling to 700-760 ℃ along with the furnace, preserving heat for 20-30 hours, and finally cooling to below 500 ℃ along with the furnace, discharging and air cooling.
Further, the temperature raised to above 850 ℃ may be 860 ℃, 870 ℃, 880 ℃, 890 ℃, 900 ℃ and all values within the range, for example, and the description is omitted because of the limitation of the space.
Further, the temperature is raised to A c1 In the heat preservation process of 30-50 ℃, the temperature is firstly increased to 640-660 ℃ for heat preservation for 2-5 hours, then the temperature is increased to 840-880 ℃ for heat preservation for 15-20 hours, and the heating rate is less than or equal to 80 ℃/h.
Further, in the long-time isothermal process of cooling to the pearlite transformation area, firstly cooling to 650-700 ℃ along with a furnace, wherein the cooling rate is less than or equal to 15 ℃/h; then heating to 700-760 ℃, heating at a speed of less than or equal to 80 ℃/h, and preserving heat for 20-30 hours; cooling to below 500 ℃ along with the furnace, discharging, and cooling at a rate less than or equal to 20 ℃/h.
Further, the temperature is raised to 1010-1040 ℃ (for example, 1010 ℃, 1015 ℃, 1020 ℃, 1025 ℃, 1030 ℃, 1035 ℃, 1040 ℃ and all values in the range are not repeated due to the limitation of the space), and the temperature is kept for 10-15 hours (for example, 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours, 14 hours, 14.5 hours and all values in the range are not repeated due to the limitation of the space);
further, cooling to 700-760 ℃ along with the furnace (for example, 700 ℃, 705 ℃, 710 ℃, 715 ℃, 720 ℃, 725 ℃, 730 ℃, 735 ℃, 740 ℃, 745 ℃, 750 ℃, 755 ℃ and all values in the range are not repeated due to space limitation), and preserving the heat for 15-20h (for example, 15h, 16h, 17h, 18h, 19h, 20h and all values in the range are not repeated due to space limitation).
Further, the temperature is raised to 1010-1040 ℃ again (for example, 1010 ℃, 1015 ℃, 1020 ℃, 1025 ℃, 1030 ℃, 1035 ℃, 1040 ℃ and all values in the range are not repeated due to the limitation of the space), and the temperature is kept for 10-15h (for example, 10h, 10.5h, 11h, 11.5h, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h and all values in the range are not repeated due to the limitation of the space);
further, the surface temperature of the forging is reduced by adopting a water-air alternate cooling mode; the surface temperature of the forging is reduced to below 350 ℃ (such as 345 ℃, 340 ℃, 335 ℃, 330 ℃, 325 ℃, 320 ℃, 315 ℃, 310 ℃, 305 ℃, 300 ℃ and all values within the range are not repeated due to the limitation of the space);
further, the low temperature furnace is kept for 6-10h (for example, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h and all values in the range are not described in detail due to the limitation of the space) at 300-350 ℃ (for example, 345 ℃, 340 ℃, 335 ℃, 330 ℃, 325 ℃, 320 ℃, 315 ℃, 310 ℃, 305 ℃, 300 ℃ and all values in the range are not described in detail due to the limitation of the space).
Further, the temperature is raised to 840-880 ℃ (for example, 840 ℃, 845 ℃, 850 ℃, 855 ℃, 860 ℃, 865 ℃, 870 ℃, 875 ℃, 880 ℃ and all values within the range are not repeated due to the limitation of the space), and the temperature is kept for 15-20 hours (for example, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours and all values within the range are not repeated due to the limitation of the space);
further, cooling to 700-760 ℃ along with the furnace (for example, 700 ℃, 705 ℃, 710 ℃, 715 ℃, 720 ℃, 725 ℃, 730 ℃, 735 ℃, 740 ℃, 745 ℃, 750 ℃, 755 ℃ and all values in the range are not repeated due to space limitation), and preserving heat for 20-30h (for example, 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h, 30h and all values in the range are not repeated due to space limitation).
Further, the steel ingot is Cr-Mo-V medium carbon medium alloy steel, and comprises the following components in percentage by mass: c:0.3-0.5%, mn:0.3-0.6%, si:0.15-1.2%, cr:4.7-5.5%, mo:1.0-3.0%, V:0.3-1.2%, and the balance of Fe and unavoidable impurities.
The technical effects of the invention include:
compared with the prior art, the Cr-Mo-V medium carbon alloy steel has higher high-temperature strength, good toughness and cold and hot fatigue resistance, and is mainly used for manufacturing forging dies, hot extrusion dies, precision forging dies, various alloy die-casting dies and the like with large impact load. The invention adopts the process mode of repeated phase change recrystallization equilibrium annealing after forging, low-temperature air alternate cooling quenching and spheroidizing annealing, effectively eliminates the inheritance of the original coarse structure, and successfully solves the problems of uneven structure, coarse grains and unstable mechanical property of the Cr-Mo-V medium carbon alloy steel. The invention can effectively refine the crystal grains of the steel, and the uniform forged structure can obtain the ideal structure of uniform and fine granular pearlite and dispersed punctiform carbide, and can also eliminate the reticulate carbide, reduce the hydrogen content in the steel, obviously improve the comprehensive mechanical property and prolong the service life.
The process method is mature and applied to die steel forgings of steel grades 4Cr5MoSiV1, 4Cr5MoSiV, 4Cr5Mo1V, 4Cr5Mo2V, 4Cr5Mo3V and the like, has stable test results, can obtain an ideal structure of uniform and fine granular pearlite and dispersed granular carbide, obviously improves the comprehensive mechanical property of the die steel, prolongs the service life of the die steel, and simultaneously can reduce the hydrogen content of the steel grade, eliminate deformation stress, reduce hardness and improve the processing property.
By combining the material characteristics of 4Cr5Mo3V and utilizing repeated phase transition recrystallization, the structure is fully and uniformly improved and the grains are refined. After forging, carrying out primary complete annealing to obtain an equilibrium state structure; then heating up austenitizing to re-form cores, and then carrying out water-air alternate rapid cooling quenching to avoid secondary carbide from crystallizing out and obtain a martensite, bainite, carbide and a small amount of residual austenite structure; then preserving heat at a low temperature of 300-350 ℃, further diffusing and redistributing carbon and alloy elements, promoting uniform tissue, and gradually reducing the hydrogen content in steel; heating to 30-50 ℃ above Ac1, preserving heat, and fusing and spheroidizing unmelted strip carbide to obtain the structure of austenite plus spherical carbide; finally, the temperature is reduced to the pearlite transformation area and isothermal temperature is maintained for a long time, and the ideal structure of the uniform and fine granular pearlite and the dispersed granular carbide is obtained.
Drawings
FIG. 1 is a process flow diagram of a method for post-forging heat treatment of a Cr-Mo-V medium carbon alloy steel of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.
As shown in FIG. 1, the process flow chart of the method for heat treatment after forging of Cr-Mo-V medium carbon alloy steel is shown.
The after-forging heat treatment method of Cr-Mo-V medium carbon alloy steel comprises the following steps:
1. immediately feeding the steel ingot into a furnace after forging and forming, waiting for material at the temperature of more than or equal to 850 ℃, and quickly heating to 1010-1040 ℃ after material alignment, and preserving heat for 10-15 hours;
heating to A after forging cm Austenitizing at a certain temperature, and heating to austenitize to re-nucleate.
2. Then cooling to 700-760 ℃ along with the furnace, and preserving heat for 15-20 hours;
the cooling rate is less than or equal to 30 ℃/h.
Then cooling to the pearlite transformation temperature zone to be isothermal, and performing primary complete annealing after forging to obtain an equilibrium state structure.
3. Heating to 1010-1040 ℃ and preserving heat for 10-15 hours;
then heat up to A cm (A cm : the final temperature of the secondary cementite dissolved into austenite during heating) for a certain time. The temperature is kept for a long time at 1010-1040 ℃, the net carbide precipitated in the forging process can be fully dissolved, the original coarse grains are eliminated, and a uniform and fine austenite plus a large amount of two-phase structure of the granular alloy carbide is obtained.
4. Adopting water-air alternative rapid cooling to reduce the surface temperature of the forging to below 450 ℃, and preserving heat for 6-10 hours in a low-temperature furnace at 300-350 ℃;
then cooling to 450 deg.c, and maintaining in a certain temperature range below 450 deg.c.
The secondary carbide is prevented from crystallizing out along the crystal by water-air alternate rapid cooling quenching, and a martensite, bainite, carbide and a small amount of residual austenite structure are obtained; then preserving heat at a low temperature of 300-350 ℃, further diffusing and redistributing carbon and alloy elements, promoting uniform structure, and gradually reducing the hydrogen content in the steel.
5. Heating to 840-880 ℃ and preserving heat for 15-20 hours;
the temperature rising rate is less than or equal to 80 ℃/h.
Firstly heating to 640-660 ℃ and preserving heat for 2-5 hours; then heating to 840-880 ℃ and preserving heat for 15-20 hours.
Thereafter, the temperature is raised to A c1 (A C1 : the starting temperature of pearlite to austenite transformation when heating) is 30-50 ℃ above, and fusing and spheroidizing unmelted strip carbide to obtain the structure of austenite plus spherical carbide.
6. Cooling to 700-760 ℃ along with the furnace, preserving heat for 20-30 hours, and finally cooling to below 500 ℃ along with the furnace, discharging and air cooling.
Firstly cooling to 650-700 ℃ along with the furnace, wherein the cooling rate is less than or equal to 15 ℃/h; then heating to 700-760 ℃, heating at a speed of less than or equal to 80 ℃/h, and preserving heat for 20-30 hours; cooling to below 500 ℃ along with the furnace, discharging, and cooling at a rate less than or equal to 20 ℃/h.
Heating to A c1 ～A cm Keeping a certain temperature for a certain time, and cooling to A along with the furnace c1 Preserving heat at a certain temperature below; cooling to the pearlite transformation area to isothermal for a long time, and obtaining an ideal structure of uniform and fine granular pearlite and dispersed granular carbide.
The steel ingot is Cr-Mo-V medium carbon medium alloy steel, at least comprises any one or combination of at least two of C element, mn element, si element, cr element, mo element or V element, and at least comprises the following components: c:0.3-0.5%, mn:0.3-0.6%, si:0.15-1.2%, cr:4.7-5.5%, mo:1.0-3.0%, V:0.3-1.2%, and the balance of Fe and unavoidable impurities.
Wherein, the content of C can be 0.32%, 0.34%, 0.36%, 0.38%, 0.40%, 0.42%, 0.44%, 0.46%, 0.48% and all values within the range, and the description is omitted because of the limitation of the space; the Mn content may be 0.32%, 0.34%, 0.36%, 0.38%, 0.40%, 0.42%, 0.44%, 0.46%, 0.48%, 0.50%, 0.52%, 0.54%, 0.56%, 0.58% and all values within the stated ranges, and will not be repeated due to space limitations; the Si content may be 0.20%, 0.25%, 0.30%, 0. 35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60%, 0.65%, 0.70%, 0.75%, 0.80%, 0.85%, 0.90%, 0.95%, 1.00%, 1.05%, 1.10%, 0.15% and all values within said range, the details of which are not repeated due to the limitations of the spread; the Cr content can be 4.7%, 4.8%, 4.9%, 5.0%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5% and all values within the stated range, and will not be described in detail due to space limitations; the Mo content may be 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8% and all values within the stated ranges, and will not be described in detail due to space limitations; the V content may be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2% and all values within the stated range, and will not be described in detail due to space limitations.
Example 1
1) Immediately feeding the steel ingot into a furnace after forging and forming, and heating to a temperature above 850 ℃ for material waiting;
2) After the materials are aligned, the temperature is kept at 1010 ℃ for 10 hours, and then the materials are cooled to 700 ℃ along with a furnace, and the temperature is kept for 15 hours;
3) Heating to 1010 ℃ again, preserving heat for 10 hours, then adopting a water-air alternate cooling mode to reduce the surface temperature of the forging to below 350 ℃, and preserving heat in a low-temperature furnace at 300 ℃ for 6 hours;
4) Then heating to 840 ℃, preserving heat for 15 hours, cooling to 700 ℃ along with the furnace, preserving heat for 20 hours, and finally cooling to about 500 ℃ along with the furnace, discharging and air cooling.
Example 2
1) Immediately feeding the steel ingot into a furnace after forging and forming, and heating to a temperature above 850 ℃ for material waiting;
2) After the materials are aligned, the temperature is kept at 1040 ℃ for 15 hours, and then the materials are cooled to 760 ℃ along with a furnace, and the temperature is kept for 20 hours;
3) Heating to 1040 ℃ again, preserving heat for 15 hours, then adopting a water-air alternate cooling mode to reduce the surface temperature of the forging to below 350 ℃, and preserving heat in a low-temperature furnace at 350 ℃ for 10 hours;
4) Then heating to 880 ℃, preserving heat for 20 hours, cooling to 760 ℃ along with the furnace, preserving heat for 30 hours, and finally cooling to about 500 ℃ along with the furnace, discharging and air cooling.
Example 3
1) Immediately feeding the steel ingot into a furnace after forging and forming, and heating to a temperature above 850 ℃ for material waiting;
2) After the materials are aligned, the temperature is kept at 1030 ℃ for 13 hours, and then the materials are cooled to 730 ℃ along with a furnace, and the temperature is kept for 18 hours;
3) Heating to 1030 ℃ again, preserving heat for 12 hours, then adopting a water-air alternate cooling mode to reduce the surface temperature of the forging to below 350 ℃, and preserving heat in a low-temperature furnace at 320 ℃ for 8 hours;
4) Then heating to 850 ℃, preserving heat for 15 hours, cooling to 730 ℃ along with the furnace, preserving heat for 25 hours, and finally cooling to about 500 ℃ along with the furnace, discharging and air cooling.
Example 4
1) Immediately feeding the steel ingot into a furnace after forging and forming, and heating to a temperature above 850 ℃ for material waiting;
2) After the materials are aligned, the temperature is kept at 1010 ℃ for 10 hours, and then the materials are cooled to 700 ℃ along with a furnace, and the temperature is kept for 15 hours;
3) Heating to 1010 ℃ again, preserving heat for 10 hours, then adopting a water-air alternate cooling mode to reduce the surface temperature of the forging to below 350 ℃, and preserving heat in a low-temperature furnace at 300 ℃ for 6 hours;
4) Then heating to 840 ℃, preserving heat for 15 hours, cooling to 700 ℃ along with the furnace, preserving heat for 20 hours, and finally cooling to about 500 ℃ along with the furnace, discharging and air cooling.
Example 5
1) Immediately feeding the steel ingot into a furnace after forging and forming, and heating to a temperature above 850 ℃ for material waiting;
2) After the materials are aligned, the temperature is kept at 1010 ℃ for 10 hours, and then the materials are cooled to 700 ℃ along with a furnace, and the temperature is kept for 15 hours;
3) Heating to 1010 ℃ again, preserving heat for 10 hours, then adopting a water-air alternate cooling mode to reduce the surface temperature of the forging to below 350 ℃, and preserving heat in a low-temperature furnace at 300 ℃ for 6 hours;
4) Then heating to 840 ℃, preserving heat for 15 hours, cooling to 700 ℃ along with the furnace, preserving heat for 20 hours, and finally cooling to about 500 ℃ along with the furnace, discharging and air cooling.
It should be noted and appreciated that various modifications and improvements of the invention described in detail above can be made without departing from the spirit and scope of the invention as claimed in the appended claims. Accordingly, the scope of the claimed subject matter is not limited by any particular exemplary teachings presented.
Applicant states that the foregoing is a further detailed description of the invention in connection with certain preferred embodiments and that the practice of the invention is not to be construed as limited thereto. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (1)
1. A method for post-forging heat treatment of a Cr-Mo-V medium carbon medium alloy steel, comprising:
the steel ingot is Cr-Mo-V medium carbon medium alloy steel, and comprises the following components in percentage by mass: c:0.3-0.5%, mn:0.3-0.6%, si:0.15-1.2%, cr:4.7-5.5%, mo:1.0-3.0%, V:0.3-1.2%, and the balance of Fe and unavoidable impurities; immediately feeding the steel ingot into a furnace after forging and forming, waiting for material at the temperature of more than or equal to 850 ℃, and quickly heating to 1010-1040 ℃ after material alignment, and preserving heat for 10-15 hours;
cooling the forge piece along with the furnace to 700-760 ℃ and preserving heat for 15-20 hours, wherein the cooling rate is less than or equal to 30 ℃/h, and carrying out primary annealing to obtain an equilibrium state structure;
heating to 1010-1040 deg.c for 10-15 hr to austenitize and re-form nucleus;
adopting water-air alternative rapid cooling to reduce the surface temperature of the forging to below 450 ℃, and preserving heat for 6-10 hours in a low-temperature furnace at 300-350 ℃;
heating to 840-880 ℃, preserving heat for 15-20 hours, heating up at a speed of less than or equal to 80 ℃/h, and heating up to a starting temperature A of pearlite to austenite transformation during heating c1 Preserving heat at the temperature of between 30 and 50 ℃ and fusing and spheroidizing the unmelted strip carbide;
cooling to 700-760 ℃ along with the furnace, preserving heat for 20-30 hours, cooling to isothermal temperature of a pearlite transformation region, cooling to below 500 ℃ along with the furnace, discharging and air cooling.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111171966.8A CN113881831B (en) | 2021-10-08 | 2021-10-08 | Post-forging heat treatment method for Cr-Mo-V medium carbon medium alloy steel |
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| CN202111171966.8A CN113881831B (en) | 2021-10-08 | 2021-10-08 | Post-forging heat treatment method for Cr-Mo-V medium carbon medium alloy steel |
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| JP2000204414A (en) * | 1999-01-14 | 2000-07-25 | Japan Steel Works Ltd:The | Production of medium carbon steel |
| US6383315B1 (en) * | 1998-01-07 | 2002-05-07 | Rasmussen Gmbh | Profile clamp and method for manufacturing a profile clamp |
| CN105838855A (en) * | 2016-05-27 | 2016-08-10 | 中原特钢股份有限公司 | Post-forging dehydrogenation annealing technology of chromium-containing high-nickel alloy steel forged piece |
| JP2018165408A (en) * | 2018-06-22 | 2018-10-25 | 株式会社神戸製鋼所 | Production method of steel material excellent in cold workability or machinability |
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| CN107058717B (en) * | 2017-01-18 | 2018-10-23 | 抚顺特殊钢股份有限公司 | Improve the heat treatment process of big specification Flat Die Steel forging material spherodized structure |
| CN108193023B (en) * | 2017-12-01 | 2020-03-27 | 内蒙古北方重工业集团有限公司 | Method for eliminating network carbide in annealing microstructure of H13 die steel |
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| US6383315B1 (en) * | 1998-01-07 | 2002-05-07 | Rasmussen Gmbh | Profile clamp and method for manufacturing a profile clamp |
| JP2000204414A (en) * | 1999-01-14 | 2000-07-25 | Japan Steel Works Ltd:The | Production of medium carbon steel |
| CN105838855A (en) * | 2016-05-27 | 2016-08-10 | 中原特钢股份有限公司 | Post-forging dehydrogenation annealing technology of chromium-containing high-nickel alloy steel forged piece |
| JP2018165408A (en) * | 2018-06-22 | 2018-10-25 | 株式会社神戸製鋼所 | Production method of steel material excellent in cold workability or machinability |
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