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Production method of 1800 MPa-grade cold-rolled steel for hot stamping forming

A technology of hot stamping forming and production method, which is applied in the production field of cold-rolled steel for 1800MPa-level hot stamping forming, can solve the problems of undisclosed key process and equipment of cold rolling welding, achieve reduction of energy consumption of production line, low alloy cost, The effect of low production cost

Active Publication Date: 2020-11-03
GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the invention patent does not disclose the key processes and equipment of cold rolling welding, pickling and rolling

Method used

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  • Production method of 1800 MPa-grade cold-rolled steel for hot stamping forming
  • Production method of 1800 MPa-grade cold-rolled steel for hot stamping forming
  • Production method of 1800 MPa-grade cold-rolled steel for hot stamping forming

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Hot-rolled raw steel strip: thickness 3.2mm, yield strength 603MPa, tensile strength 740MPa, elongation after fracture A 50mm was 25.0%.

[0034] Primary Bell Furnace Annealing:

[0035] The annealing hot spot is 726°C / 733°C, the holding time is 18h, and the annealing process adopts a hydrogen atmosphere. The heating rate from room temperature to 650°C is 79.9°C / h, and the average hydrogen flow rate is 39.8m 3 / h; 650℃~700℃ heating rate is 33.9℃ / h, 700~740℃ heating rate is 24.8℃ / h, when the hot spot in the heating section is ≥650℃, the average hydrogen flow rate is 25.0m 3 / h. The average flow rate of hydrogen is 17.8m at 6 hours before heat preservation 3 / h. When cooling to 580°C, switch to air-cooling mode and cool at full speed, air-cool to 380°C, switch to water-cooling mode and cool at full speed, and the temperature of the oven is 98°C.

[0036] Continuous flash butt welding:

[0037] The welding mode is dripping oil + annealing mode, the flash voltage ...

Embodiment 2

[0047] Hot-rolled raw steel strip: thickness 3.0mm, yield strength 611MPa, tensile strength 752MPa, elongation after fracture A 50mm was 24.5%.

[0048] Primary Bell Furnace Annealing:

[0049] The annealing hot spot is 727°C / 731°C, the holding time is 18h, and the annealing process uses a hydrogen atmosphere. The heating rate from room temperature to 650°C is 80.0°C / h, and the average hydrogen flow rate is 39.9m 3 / h; 650℃~700℃ heating rate is 33.6℃ / h, 700~740℃ heating rate is 24.9℃ / h, when the hot spot in the heating section is ≥650℃, the average flow rate of hydrogen is 24.8m 3 / h. The average flow rate of hydrogen is 17.9m at 6h before heat preservation 3 / h. When cooling to 580°C, switch to air-cooling mode and cool at full speed, air-cool to 380°C, switch to water-cooling mode and cool at full speed, and the temperature out of the furnace is 95°C.

[0050] Continuous flash butt welding:

[0051] The welding mode is dripping oil + annealing mode, the flash volt...

Embodiment 3

[0061] Hot-rolled raw steel strip: thickness 2.4mm, yield strength 650MPa, tensile strength 765MPa, elongation after fracture A 50mm was 23.0%.

[0062] Primary Bell Furnace Annealing:

[0063] The annealing hot spot is 728°C / 734°C, the holding time is 18h, and the annealing process adopts a hydrogen atmosphere. The heating rate from room temperature to 650°C is 79.7°C / h, and the average hydrogen flow rate is 39.8m 3 / h; 650℃~700℃ heating rate is 33.8℃ / h, 700~740℃ heating rate is 25.0℃ / h, when the hot spot in the heating section is ≥650℃, the average flow rate of hydrogen is 24.9m 3 / h. The average flow rate of hydrogen is 18.0m at 6 hours before heat preservation 3 / h. When cooling to 580°C, switch to air-cooling mode and cool at full speed; when air-cooling to 380°C, switch to water-cooling mode and cool at full speed, and the temperature out of the oven is 97°C.

[0064] Continuous flash butt welding:

[0065] The welding mode is dripping oil + annealing mode, th...

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Abstract

The invention discloses 1800 MPa-grade cold-rolled steel for hot stamping forming. The 1800 MPa-grade cold-rolled steel is composed of the following chemical components including, by weight, 0.25%-0.35% of C, 0.20%-0.40% of Si, 1.10%-1.45% of Mn, less than or equal to 0.020% of P, less than or equal to 0.012% of S, 0.030%-0.060% of Als, 0.25%-0.60% of Cr, 0.030%-0.060% of Ti, 0.0025%-0.0055% of Band the balance Fe and inevitable impurities. According to the process route, the production method comprises the steps of raw material steel strip hot rolling, primary bell-type furnace annealing, continuous flash butt welding, acid pickling, cold continuous rolling, secondary bell-type furnace annealing, leveling and finished product obtaining. After hot stamping forming, a 1800 MPa-grade cold-rolled steel strip for hot stamping forming has the yield strength of 1359-1369 MPa, the tensile strength of 1821-1846 MPa and the percentage elongation after fracture of 6.5%-6.0% , meets the use requirements of the 1800 MPa-grade steel strip for hot stamping forming, and has the characteristics of low cost and high efficiency.

Description

technical field [0001] The invention belongs to the technical field of cold-rolled high-strength steel production, and in particular relates to a production method of cold-rolled steel for 1800MPa-level hot stamping. Background technique [0002] With the continuous development of the automobile industry towards lightweight, the research on "stronger and lighter" materials such as advanced high-strength steel and high-strength alloys for automobiles is also deepening. When the tensile strength of cold-rolled high-strength steel for automobiles exceeds 1000MPa, the plastic deformation range of the steel becomes smaller and the formability is poor; moreover, the stamping force required in the processing process is high, and the stamping equipment is high, resulting in high production costs. . When it is stamped and deformed at room temperature, it is easy to crack and wrinkle, which leads to serious springback of the formed part. Especially when the strength reaches 1300MPa o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/28C22C38/32C21D8/02C21D1/26C21D1/74
CPCC22C38/02C22C38/04C22C38/06C22C38/28C22C38/32C21D8/0226C21D8/0263C21D8/0236C21D8/0273C21D8/0242C21D1/26C21D1/74
Inventor 罗晓阳赵小龙狄彦军王生东王正仲周文宾苏晓智
Owner GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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