阅读说明：本技术 70t级锻造12Cr2Mo1R(H)钢锭的模铸方法 (Die casting method for 70 t-grade forged 12Cr2Mo1R (H) steel ingot ) 是由 甄光楠 夏保卫 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种70t级锻造12Cr2Mo1R(H)钢锭的模铸方法,所述模铸方法包括保护渣选择、浇注过热度控制、浇注速度控制、保护浇注控制、退火控制工序。本发明操作简便易行,既能提高钢锭内部质量,减少钢锭头部疏松、缩孔等缺陷,也能防止钢锭表面裂纹,减少70t级锻造12Cr2Mo1R(H)钢锭因裂纹缺陷造成的废品计划外,生产锻造锭轧出的钢板符合NB/T47013.3-2015验收等级Level T1级,探伤合格率≥98.2%,且钢锭无裂纹缺陷。(The invention discloses a die casting method for a 70 t-grade forged 12Cr2Mo1R (H) steel ingot, which comprises the working procedures of casting powder selection, casting superheat degree control, casting speed control, protective casting control and annealing control. The method is simple and easy to operate, can improve the internal quality of the steel ingot, reduce the defects of looseness, shrinkage cavity and the like of the head of the steel ingot, prevent cracks on the surface of the steel ingot, reduce the possibility of rejection caused by crack defects of 70T-grade forged 12Cr2Mo1R (H) steel ingots, produce steel plates rolled out of forged ingots and accord with NB/T47013.3-2015 acceptance grade Level T1 grade, the flaw detection qualification rate is more than or equal to 98.2 percent, and the steel ingot has no crack defects.)

1. A die casting method for a 70 t-grade forged 12Cr2Mo1R (H) steel ingot is characterized by comprising the working procedures of casting powder selection, casting superheat degree control, casting speed control, protective casting control and annealing control; the annealing process comprises the following steps: the charging temperature is more than or equal to 400 ℃, the steel is firstly subjected to steel sealing for 10 hours at 280-300 ℃, then the temperature is increased to 900-920 ℃ at the speed of 46-50 ℃/h, then the temperature is kept for 46-48 hours, and finally the temperature is reduced to 150-200 ℃ at the speed of 47-50 ℃/h, and then the steel is discharged.

2. A die casting method for a 70 t-grade forged 12Cr2Mo1R (H) steel ingot according to claim 1, wherein the mold flux selecting step uses low-carbon mold flux, and the hemispherical point temperature of the low-carbon mold flux is 1120-1170 ℃.

3. A die casting method of a 70 t-grade forged 12Cr2Mo1R (H) steel ingot according to claim 1, wherein the casting superheat degree control step is performed such that the casting superheat degree of the forged ingot is controlled to be 46-48 ℃.

4. A die casting method of a 70 t-grade forged 12Cr2Mo1R (H) steel ingot according to claim 1, wherein in the pouring speed control procedure, the aperture of a pouring nozzle is 45mm, the main body pouring time is 22-26 min, and the cap opening pouring time is 8-10 min.

5. A die casting method of a 70 t-grade forged 12Cr2Mo1R (H) steel ingot according to claim 1, wherein the casting control procedure is full-sealed casting, molten steel is completely isolated from air in the casting process, the casting is performed for 24-26H, and the ingot is immediately placed in an annealing furnace for annealing after being demolded.

6. A die casting method of a 70 t-grade forged 12Cr2Mo1R (H) steel ingot according to any one of claims 1-5, wherein the die casting method produces a forged ingot which is 70-80 t sixteen-edged forged ingot.

7. A die casting method for a 70T-grade forged 12Cr2Mo1R (H) steel ingot according to any one of claims 1-5, wherein the thickness of a steel plate rolled by the die casting method for producing the forged ingot is 160-190 mm, the steel plate meets NB/T47013.3-2015 acceptance Level T1 grade, the flaw detection qualification rate is not less than 98.2%, and the steel ingot has no crack defects.

8. A die casting method for forging a 12Cr2Mo1R (H) steel ingot of 70t grade according to any one of claims 1-5, wherein the die casting method produces a steel plate rolled from the forged ingot with yield strength not less than 320MPa, tensile strength 520-680MPa and impact at-30 ℃ not less than 100J.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a die casting method for a 70 t-grade forged 12Cr2Mo1R (H) steel ingot.

Background

The 12Cr2Mo1R (H) steel has good high temperature resistance, high pressure resistance, corrosion resistance and hydrogen resistance, is often applied to the manufacture of equipment such as a hot high pressure separator, a hydrogenation reactor and the like, and requires that a steel plate of the manufactured equipment not only has excellent mechanical property and internal quality, but also has good surface quality due to harsh use environment of the equipment. With the development of petrochemical projects, equipment is large-sized, intensive and green, the quality improvement and upgrading of the equipment inevitably cause the improvement of the quality of steel for the equipment, and steel plates are developed towards the directions of large thickness and large single weight.

The 12Cr2Mo1R (H) steel has high alloy content, poor molten steel fluidity, difficult floating of inclusions, easier slag rolling and easy deposition and aggregation of the inclusions at the tail of a steel ingot. In the process of cooling steel ingots, hard and brittle structures such as bainite are easily generated in the 12Cr2Mo1R (H), so that large structural stress and thermal stress are generated in steel, various types of cracks are easily generated, the problems of scrapping of blanks and steel plates or surface quality of finished products are caused, production and delivery are influenced, and the production cost is increased.

Based on this study, a die casting and annealing method for a 70 t-grade forged 12Cr2Mo1R (H) steel ingot. The method is simple and easy to operate, the comprehensive cost is low, the flaw detection qualification rate of the rolled steel plate is more than or equal to 98.2 percent, and the steel ingot has no crack defects.

Disclosure of Invention

The invention aims to provide a die casting method for forging a 12Cr2Mo1R (H) steel ingot of 70t grade. According to the invention, through the selection of the casting powder, the control of the superheat degree of molten steel casting, the control of the casting speed, the control of protective casting and the control of annealing, the ordered solidification of the steel ingot is realized, inclusions effectively float and are eliminated, no large-scale endogenous inclusions and external inclusions are accumulated at the bottom of the steel ingot, no layering and shrinkage phenomena exist in the steel ingot, no cracks exist on the surface of the steel ingot, and the like.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a die casting method for a 70 t-grade forged 12Cr2Mo1R (H) steel ingot comprises the working procedures of casting powder selection, casting superheat degree control, casting speed control, protective casting control and annealing control; the annealing process comprises the following steps: the charging temperature is more than or equal to 400 ℃, the steel is firstly subjected to steel sealing for 10 hours at 280-300 ℃, then the temperature is increased to 900-920 ℃ at the speed of 46-50 ℃/h, then the temperature is kept for 46-48 hours, and finally the temperature is reduced to 150-200 ℃ at the speed of 47-50 ℃/h, and then the steel is discharged.

According to the protective slag selection process, the low-carbon protective slag is used, the hemispherical point temperature of the low-carbon protective slag is 1120-1170 ℃, the lower hemispherical point temperature is higher, the protective slag is easier to melt, and molten steel is not easy to be involved in the protective slag, so that the tail inclusion defect is formed.

According to the pouring superheat degree control process, the pouring superheat degree of a forging ingot is controlled to be 46-48 ℃. The high superheat degree is adopted, so that the long pouring time is prevented, the molten steel temperature is low in the later pouring period, impurities float up difficultly and are gathered at the tail part.

According to the pouring speed control procedure, the aperture of a pouring nozzle is 45mm, the pouring time of a body is 22-26 min, and the pouring time of a cap opening is 8-10 min. The 45mm aperture nozzle can more easily keep the casting flow shape and control the casting speed in the casting process, reduce the secondary oxidation of molten steel and reduce the surface cracks of steel ingots, and the operation is simpler and more convenient.

The protective casting control procedure of the invention comprises the steps of full-sealing protective casting, completely isolating molten steel from air in the casting process, preventing the molten steel from secondary oxidation, demoulding after 24-26h of casting, and timely loading in an annealing furnace for annealing after demoulding.

The die casting method provided by the invention is used for producing 70-80 t of sixteen-edge forged ingots.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method is 160-190 mm, the steel plate conforms to NB/T47013.3-2015 acceptance Level T1, the flaw detection qualification rate is more than or equal to 98.2%, and the steel ingot has no crack defects.

The yield strength of the steel plate rolled by the forging ingot produced by the die casting method is more than 320MPa, the tensile strength is 520-680MPa, and the impact at minus 30 ℃ is more than or equal to 100J.

The steel 12Cr2Mo1R (H) product for the hydrogenation reactor produced by the die casting method of 70 t-grade forged 12Cr2Mo1R (H) steel ingot and the performance detection method standard reference are as follows: GB713 Steel sheets for boilers and pressure vessels; and (3) flaw detection standard reference: NB/T47013.3 nondestructive testing of pressure-bearing equipment.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the invention uses low-carbon covering slag with lower hemispherical point temperature, the covering slag is easier to melt, and the molten steel is not easy to be rolled into the covering slag to form the defect of tail inclusion. 2. The invention adopts higher superheat degree to prevent long pouring time, low molten steel temperature in the later pouring period, difficult floating of impurities and aggregation at the tail part. 3. The invention adopts the water gap with the aperture of 45mm to more easily keep the casting flow shape and control the casting speed in the casting process, reduces the secondary oxidation of molten steel and the surface cracks of steel ingots, and has simpler and more convenient operation. 4. The invention adopts full-sealing protection pouring, and the molten steel is completely isolated from air in the pouring process, thereby preventing the molten steel from secondary oxidation. 5. The annealing process can effectively release the internal stress in the steel, and the steel ingot and the rolled steel plate have no crack defects. 6. The method is simple and easy to operate, can improve the internal quality of the steel ingot, reduce the defects of looseness, shrinkage cavity and the like of the head of the steel ingot, prevent cracks on the surface of the steel ingot, reduce the possibility of rejection caused by crack defects of 70T-grade forged 12Cr2Mo1R (H) steel ingots, produce steel plates rolled out of forged ingots and accord with NB/T47013.3-2015 acceptance grade Level T1 grade, the flaw detection qualification rate is more than or equal to 98.2 percent, and the steel ingot has no crack defects.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example 1

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) a covering slag selection procedure, wherein low-carbon covering slag is used, and the hemispherical point temperature of the low-carbon covering slag is 1150 ℃;

(2) a pouring superheat degree control procedure, wherein the pouring superheat degree of a forging ingot is controlled to be 46 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 22min, and the pouring time of the cap opening is 8 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 24h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) and an annealing control procedure, wherein the charging temperature is 400 ℃, the steel is firstly subjected to cold covering at 280 ℃ for 10h, then the temperature is increased to 900 ℃ at the temperature increasing speed of 48 ℃/h, then the temperature is kept for 46h, and finally the temperature is reduced to 150 ℃ at the temperature decreasing speed of 48 ℃/h to be discharged.

The die casting method of this example produces a 70t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 98.9%, and the steel ingot has no crack defects.

The thickness of the steel plate rolled by the forging ingot produced by the die casting method of the embodiment is 160mm, the yield strength is 330MPa, the tensile strength is 520MPa, and the impact is 102J at-30 ℃.

Example 2

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) the method comprises the following steps of (1) selecting a protective slag, wherein low-carbon protective slag is used, and the hemispherical point temperature of the low-carbon protective slag is 1120 ℃;

(2) a pouring superheat degree control process, wherein the pouring superheat degree of a forging ingot is controlled to be 47 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 24min, and the pouring time of the cap opening is 9 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 26h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) and (3) annealing control, wherein the charging temperature is 410 ℃, the steel is firstly subjected to steel sealing at 300 ℃ for 10h, then the temperature is increased to 920 ℃ at the heating rate of 50 ℃/h, then the temperature is kept for 48h, and finally the temperature is reduced to 200 ℃ at the cooling rate of 50 ℃/h, and then the steel is discharged.

The die casting method of this example produces a 70t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 99.5%, and the steel ingot has no crack defects.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method of the embodiment is 170mm, the yield strength is 340MPa, the tensile strength is 550MPa, and the impact at minus 30 ℃ is 110J.

Example 3

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) a covering slag selection procedure, wherein low-carbon covering slag is used, and the hemispherical point temperature of the low-carbon covering slag is 1170 ℃;

(2) a pouring superheat degree control process, wherein the pouring superheat degree of a forging ingot is controlled to be 48 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 26min, and the pouring time of the cap opening is 10 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 25h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) and (3) an annealing control procedure, wherein the charging temperature is 408 ℃, the steel is firstly sealed at 295 ℃ for 10h, then the temperature is increased to 910 ℃ at the temperature increasing speed of 49 ℃/h, then the temperature is kept for 46.5h, and finally the temperature is reduced to 180 ℃ at the temperature reducing speed of 49.5 ℃/h to be discharged.

The die casting method of this example produced a 80t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 99.2%, and the steel ingot has no crack defects.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method of the embodiment is 190mm, the yield strength is 355MPa, the tensile strength is 680MPa, and the impact at minus 30 ℃ is 105J.

Example 4

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) the method comprises the following steps of (1) selecting a working procedure of the covering slag, wherein low-carbon covering slag is used, and the hemispherical point temperature of the low-carbon covering slag is 1130 ℃;

(2) a pouring superheat degree control process, wherein the pouring superheat degree of a forging ingot is controlled to be 48 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 25min, and the pouring time of the cap opening is 8 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 25h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) annealing control process, wherein the charging temperature is 412 ℃, the steel is firstly choked at 285 ℃ for 10h (ignition and small fire), then the temperature is increased to 920 ℃ at the temperature rising speed of 48.5 ℃/h, then the temperature is kept for 47.5h, and finally the temperature is reduced to 175 ℃ at the temperature falling speed of 48.5 ℃/h, and the steel is taken out of the furnace

The die casting method of this example produced a 80t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 99.7%, and the steel plate has no crack defects.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method of the embodiment is 185mm, the yield strength is 365MPa, the tensile strength is 560MPa, and the impact is 125J at-30 ℃.

Example 5

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) a covering slag selection procedure, wherein low-carbon covering slag is used, and the hemispherical point temperature of the low-carbon covering slag is 1140 ℃;

(2) a pouring superheat degree control procedure, wherein the pouring superheat degree of a forging ingot is controlled to be 46 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 23min, and the pouring time of the cap opening is 8.5 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 24h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) and an annealing control procedure, wherein the charging temperature is 420 ℃, steel sealing is carried out for 10h at 293 ℃, then the temperature is increased to 915 ℃ at the speed of 46.8 ℃/h, then the temperature is kept for 47.5h, and finally the temperature is reduced to 190 ℃ at the speed of 48.5 ℃/h, and then the steel is discharged.

The die casting method of this example produced a 76t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 98.7%, and the steel ingot has no crack defects.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method of the embodiment is 175mm, the yield strength is 375MPa, the tensile strength is 600MPa, and the impact is 120J at-30 ℃.

Example 6

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) the method comprises the following steps of (1) selecting a working procedure of covering slag, wherein low-carbon covering slag is used, and the hemispherical point temperature of the low-carbon covering slag is 1146 ℃;

(2) a pouring superheat degree control process, wherein the pouring superheat degree of a forging ingot is controlled to be 47.5 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 24min, and the pouring time of the cap opening is 9.5 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 25.5h, demolding, and timely loading into an annealing furnace for annealing after demolding;

(5) and (3) annealing control, wherein the charging temperature is 410.5 ℃, the annealing is carried out for 10h at 288 ℃, then the temperature is increased to 915 ℃ at the speed of 49.5 ℃/h, then the temperature is kept for 47.5h, and finally the temperature is reduced to 185 ℃ at the speed of 48.5 ℃/h for discharging.

The die casting method of this example produces a 72t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 98.8%, and the steel ingot has no crack defects.

The thickness of the steel plate rolled by the forging ingot produced by the die casting method of the embodiment is 180mm, the yield strength is 380MPa, the tensile strength is 600MPa, and the impact is 115J at minus 30 ℃.

Example 7

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) a covering slag selection procedure, wherein low-carbon covering slag is used, and the hemispherical point temperature of the low-carbon covering slag is 1160 ℃;

(2) a pouring superheat degree control procedure, wherein the pouring superheat degree of a forging ingot is controlled to be 46 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 26min, and the pouring time of the cap opening is 10 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 26h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) and an annealing control procedure, wherein the charging temperature is 405 ℃, the steel is firstly subjected to steel sealing at 298 ℃ for 10h, then the temperature is increased to 918 ℃ at the temperature increasing speed of 46 ℃/h, then the temperature is kept for 48h, and finally the temperature is reduced to 200 ℃ at the temperature decreasing speed of 49 ℃/h to be discharged.

The die casting method of this example produced a 79t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 99.0%, and the steel ingot has no crack defects.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method of the embodiment is 165mm, the yield strength is 400MPa, the tensile strength is 580MPa, and the impact is 125J at-30 ℃.

Example 8

The die casting method for forging the 12Cr2Mo1R (H) steel ingot of 70t grade in the embodiment comprises the following specific process steps of casting powder selection, casting superheat degree control, casting speed control, casting protection control and annealing control:

(1) a protective slag selection procedure, wherein low-carbon protective slag is used, and the hemispherical point temperature of the low-carbon protective slag is 1150 ℃;

(2) a pouring superheat degree control process, wherein the pouring superheat degree of a forging ingot is controlled to be 48 ℃;

(3) controlling the pouring speed, wherein the aperture of a pouring water gap is 45mm, the pouring time of the body is 22min, and the pouring time of the cap opening is 9 min;

(4) the protective pouring control procedure is full-sealed protective pouring, and molten steel is completely isolated from air in the pouring process; pouring for 24h, demolding, and timely loading in an annealing furnace for annealing after demolding;

(5) and an annealing control procedure, wherein the charging temperature is 408 ℃, the steel is firstly blocked at 289 ℃ for 10h, then the temperature is increased to 920 ℃ at the heating rate of 47 ℃/h, then the temperature is kept for 47h, and finally the temperature is reduced to 150 ℃ at the cooling rate of 47 ℃/h to be discharged.

The die casting method of this example produced a 74t hex forged ingot.

The steel plate rolled by the forged ingot produced by the die casting method of the embodiment meets the NB/T47013.3-2015 acceptance Level T1 Level, the flaw detection qualification rate is 99.1%, and the steel ingot has no crack defects.

The thickness of a steel plate rolled by a forged ingot produced by the die casting method of the embodiment is 172mm, the yield strength is 380MPa, the tensile strength is 580MPa, and the impact is 130J at-30 ℃.

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.