CN114410894A - Method for reducing quenching cracks of 12Cr2Mo1VR steel - Google Patents
Method for reducing quenching cracks of 12Cr2Mo1VR steel Download PDFInfo
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- CN114410894A CN114410894A CN202111621569.6A CN202111621569A CN114410894A CN 114410894 A CN114410894 A CN 114410894A CN 202111621569 A CN202111621569 A CN 202111621569A CN 114410894 A CN114410894 A CN 114410894A
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- quenching
- steel
- cracks
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- 12cr2mo1vr
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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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
-
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
-
- 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 relates to a method for reducing quenching cracks of 12Cr2Mo1VR steel, which comprises the steps of steel plate smelting, rolling and heat treatment, wherein the heat treatment step adopts the processes of low-temperature quenching, water-entering red returning and tempering, the quenching heating temperature is 900-. The content of P, H in steel is reduced in the smelting process; the rolling process adopts a high-temperature large-reduction rolling process. The 12Cr2Mo1VR steel produced by the method has no quenching crack after quenching, no aging crack after placement, and stable steel plate performance, the yield strength is 450-550MPa, the tensile strength is 620-670MPa, and the impact at minus 20 ℃ is more than or equal to 120J.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for reducing quenching cracks of 12Cr2Mo1VR steel.
Background
The main reason for the quench cracking of steel sheets is that the tensile stress generated during cooling exceeds the tensile strength of the steel. Inclusions, bulk carbides, and various micro-cracks existing in steel, which have an adverse effect on the strength of steel, promote cracking of a workpiece during quenching and cooling. According to the formation time of the quench cracks, the quench cracks are divided into cracks formed during quenching and cracks generated during the room-temperature standing process after quenching, which are also called age cracks.
The alloy content of the 12Cr2Mo1VR steel is high, and the production period is long. In the smelting process, a large amount of alloy and slagging agent are required to be added, and the control difficulty of harmful elements and impurities is high; during the casting process, obvious composition segregation phenomenon is easy to generate, so that a large amount of microcrack defects are easy to generate in the ingot blank. Because the performance requirements of the steel plate are strict, a quenching and tempering production process is required in the heat treatment process. The steel plate is easy to generate quenching cracks in the quenching process due to the micro-crack defects caused by the segregation of harmful elements, inclusions and components in the steel.
For the 12Cr2Mo1VR steel plate, if cracks are generated after quenching, the steel plate is used after repair if the cracks are light, and the steel plate is directly rejected if the cracks are heavy, so that economic loss is caused; if the aging cracks occur, the steel plate cracks after delivery to users, so that the loss of the users is compensated, and the enterprises are extremely badly influenced. Therefore, the invention optimizes the steel plate smelting, rolling and heat treatment processes to reduce the quenching cracks of the 12Cr2Mo1VR steel plate.
Disclosure of Invention
The invention aims to provide a method for reducing quenching cracks of 12Cr2Mo1VR steel, wherein the 12Cr2Mo1VR steel produced by the method has no quenching cracks after quenching, has no age cracks after being placed, and has stable steel plate performance.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a method for reducing quenching cracks of 12Cr2Mo1VR steel comprises the steps of steel plate smelting, rolling and heat treatment, wherein the heat treatment process adopts the processes of low-temperature quenching, water entry and red return and tempering, the quenching heating temperature is 900-.
Further, the quenching and heating are carried out, then the water is added for 15-20min, and the temperature of the red returning is 250-300 ℃.
Further, the tempering temperature is 690-.
Furthermore, the rolling process adopts a high-temperature large-reduction rolling process, the rolling temperature is 950-.
Furthermore, the steel plate smelting process requires slag-free tapping of an electric furnace, the steel plate is subjected to P removal treatment after sitting in a refining furnace, the P removal is required to be less than or equal to 0.002%, the P content of a finished product after smelting is less than or equal to 0.005%, and the H content is less than or equal to 0.0002%.
Further, the refined molten steel is subjected to vacuum degassing treatment, the argon blowing amount is increased in the vacuum process, the argon flow is 100-300L/min, and the pressure is 0.4-0.5 MPa.
Further, the soft blowing time is guaranteed to be more than or equal to 10min after vacuum, the molten steel is required to be bare, the flow of argon is 25-35L/min, and the pressure is 0.2-0.3 MPa.
The invention principle of the invention is as follows: in the smelting process, the electric furnace discharges steel without slag and strictly controls the P content, so that the phenomenon of quenching cracks caused by high P content can be reduced; after refining, carrying out vacuum degassing treatment, and strictly controlling the flow and pressure of argon, so that the content of H in steel can be further reduced, and quenching cracks caused by overhigh H are reduced; performing soft blowing on the molten steel after vacuum, strictly controlling the flow and pressure of the soft argon blowing gas, ensuring that impurities float sufficiently, and reducing the content of the impurities in the steel; a high-temperature high-reduction rolling process is adopted in the rolling process, so that the pressing of microcrack defects in the steel is ensured; the quenching process adopts the processes of low-temperature quenching, water cooling and tempering, so that the coarsening of crystal grains can be avoided and the quenching crack tendency can be reduced on the premise of ensuring the performance of the steel plate.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1) the produced 12Cr2Mo1VR steel has no quenching crack after quenching and no aging crack after being placed; 2) the produced 12Cr2Mo1VR steel has stable performance, the yield strength is 450-550MPa, the tensile strength is 620-670MPa, and the impact at-20 ℃ is more than or equal to 120J; 3) the method only optimizes the process, does not increase equipment investment, and has low production cost.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
A method for reducing quenching cracks of 12Cr2Mo1VR steel comprises the following steps of controlling the processes of steel plate smelting, rolling and heat treatment:
in the steel plate smelting process, slag-free steel tapping is carried out by an electric furnace, the P removing treatment is carried out after a refining furnace is arranged, the P removing is required to be less than or equal to 0.002 percent, the P content of a finished product is less than or equal to 0.005 percent after the smelting is finished, and the H content is less than or equal to 0.0002 percent; after refining, the molten steel is subjected to vacuum degassing treatment, the argon blowing amount is increased in the vacuum process, the argon flow is 100-300L/min, and the pressure is 0.4-0.5 Mpa; and ensuring that the soft blowing time is more than or equal to 10min after vacuum, wherein the molten steel is required to be bare, the flow of argon is 25-35L/min, and the pressure is 0.2-0.3 MPa.
The rolling process adopts a high-temperature large-reduction rolling process, the rolling temperature is 950-.
The heat treatment process adopts the processes of low-temperature quenching, water-entering red returning and tempering, the quenching heating temperature is 900-; after quenching and heating, the mixture is put into water for 15-20min, and the temperature of the mixture is returned to 250-; the tempering temperature is 690 and 710 ℃, and the temperature is kept for 150 and 180 min.
Examples 1 to 8
In examples 1 to 8, the tapping condition of the electric furnace, the P content after P removal, the P content and the H content of the finished product after smelting are shown in Table 1; the argon flow and the pressure in the vacuum degassing and soft blowing processes are shown in the table 2; the rolling temperature and the rolling reduction in the steel plate rolling process are shown in Table 3; the quenching temperature, the heat preservation time, the water inlet time, the re-reddening temperature, the tempering temperature and the heat preservation time of the steel plate in the heat treatment process are shown in a table 4.
The steel sheets produced in examples 1 to 8 were found to have quench cracking, yield strength, tensile strength and impact properties shown in Table 5.
TABLE 1 Steel tapping condition of electric furnace, P content after P removal, P and H contents of finished product after smelting in the smelting process of each example
TABLE 2 argon flow, pressure during vacuum degassing and Soft blowing for each example
TABLE 3 Rolling temperature and reduction in Rolling of Steel sheet for Each example
TABLE 4 Heat treatment Process parameters of the Steel sheets of the examples
TABLE 5 Properties of the steel sheets of examples
As shown in Table 5, the 12Cr2Mo1VR steel produced by the method provided by the invention has no quenching cracks after quenching, no aging cracks after placing, and stable steel plate performance, the yield strength is 450-550MPa, the tensile strength is 620-670MPa, and the impact at-20 ℃ is more than or equal to 120J
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (9)
1. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel is characterized by comprising the steps of steel plate smelting, rolling and heat treatment, wherein the heat treatment process adopts a low-temperature quenching process, a water-entering and red-returning process and a tempering process, the quenching heating temperature is 900-920 ℃, and the heat preservation time is 120-150 min.
2. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel as claimed in claim 1, wherein the quenching heating is carried out in water for 15-20min at the temperature of 250-300 ℃.
3. The method for reducing the 12Cr2Mo1VR steel quenching cracks as claimed in claim 1 or 2, wherein the tempering temperature is 690-710 ℃ and the temperature is 150-180 min.
4. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel as claimed in claim 1 or 2, wherein the rolling process adopts a high-temperature large-reduction rolling process, the rolling temperature is 950-.
5. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel as claimed in claim 1, wherein the smelting process requires slag-free tapping from an electric furnace, the P removal treatment is performed after the refining furnace, the P removal treatment is required to be less than or equal to 0.002%, the P content of the finished product is less than or equal to 0.005% after the smelting is completed, and the H content is less than or equal to 0.0002%.
6. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel as claimed in claim 5, wherein the refined molten steel is vacuum degassed with an increased argon blowing amount, an argon flow of 100L/min and a pressure of 0.4-0.5 MPa.
7. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel as claimed in claim 6, wherein the soft blowing time is guaranteed to be more than or equal to 10min after vacuum, no exposure of molten steel is required, the flow of argon is 25-35L/min, and the pressure is 0.2-0.3 MPa.
8. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel according to any one of claims 1-7, wherein the 12Cr2Mo1VR steel produced by the method has no quenching cracks after quenching and no age cracks after being placed.
9. The method for reducing the quenching cracks of the 12Cr2Mo1VR steel as claimed in any one of claims 1-7, wherein the 12Cr2Mo1VR steel produced by the method has stable performance, the yield strength of 450-550MPa, the tensile strength of 620-670MPa, and the impact at-20 ℃ is not less than 120J.
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| CN202111621569.6A CN114410894B (en) | 2021-12-28 | 2021-12-28 | Method for reducing quenching cracks of 12Cr2Mo1VR steel |
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| CN202111621569.6A CN114410894B (en) | 2021-12-28 | 2021-12-28 | Method for reducing quenching cracks of 12Cr2Mo1VR steel |
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Citations (14)
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2021
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| KR20010016977A (en) * | 1999-08-06 | 2001-03-05 | 전선기 | Method of producing a bar steel using a direct quenching and self tempering |
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