Steel member, steel sheet, and methods for producing same

A manufacturing method and technology of steel components, applied in the direction of manufacturing tools, furnaces, heat treatment equipment, etc.

Active Publication Date: 2020-10-20
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It should be noted that high-strength steel sheets can be easily processed by roll forming instead of press forming, but its application is limited to parts having a uniform cross-section in the longitudinal direction

Method used

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  • Steel member, steel sheet, and methods for producing same
  • Steel member, steel sheet, and methods for producing same
  • Steel member, steel sheet, and methods for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0179] The slabs listed in Tables 1-1 to 1-2 were hot-rolled to obtain hot-rolled steel sheets with a thickness of 3.0 mm. In the hot rolling process, the slab heating temperature is set to 1250°C, the parameter S1 from rough rolling to finish rolling is set to 22657, the finish rolling end temperature is set to 930°C, and the average cooling rate is 20°C. °C / sec cooling to coiling, coiling at 550 °C.

[0180] The parameter S1 is controlled to 22657 within the range of 1 to 60 seconds from the end of rough rolling to the start of finish rolling, and the average temperature of the rough profile from the end of rough rolling to the start of finish rolling of 950 to 1150°C. Thereafter, the hot-rolled steel sheet was descaled for 30 seconds with hydrochloric acid having a concentration of 12% and a temperature of 90°C. Thereafter, cold rolling was performed by a cold rolling mill to obtain a cold-rolled steel sheet having a thickness of 1.4 mm.

[0181] The above-mentioned cold-...

Embodiment 2

[0199] The slabs listed in Tables 1-1 to 1-2 were hot-rolled to obtain hot-rolled steel sheets with a thickness of 3.0 mm. In the hot rolling process, the slab heating temperature is set to 1250°C, the parameter S1 from the end of rough rolling to the start of finish rolling is set to 22657, the finishing temperature is set to 930°C, and the temperature is set at 20°C / Second cooling to coiling, coiling at 550°C. The parameter S1 is controlled to 22657 within the range of 1 to 60 seconds from the end of rough rolling to the start of finish rolling, and the average temperature of the rough profile from the end of rough rolling to the start of finish rolling of 950 to 1150°C. Thereafter, the hot-rolled steel sheet was descaled for 30 seconds with hydrochloric acid having a concentration of 12% and a temperature of 90°C. Thereafter, cold rolling was performed by a cold rolling testing machine to obtain a cold-rolled steel sheet having a thickness of 1.4 mm.

[0200] With respec...

Embodiment 3

[0205] The hot rolling shown in Tables 4-1 and 4-2 was carried out on slabs having steel components of steel No. A28 and A29 among the steel types shown in Table 1-1 (a part was heated using a profile heater. ), pickling (hydrochloric acid or sulfuric acid), and manufactured hot-rolled steel sheets (thickness 2.8mm). The evaluation results of the structure of the obtained steel sheets are shown in Tables 4-1 and 4-2. It should be noted that t1 (seconds) in Tables 4-1 and 4-2 is the time from the end of rough rolling to the start of finish rolling, and T1 (°C) is the temperature of the rough profile from the end of rough rolling to the start of finish rolling. The average temperature, S1, is a value obtained by (T1+273)×(logt1+20).

[0206] However, the unit of t1 in the formula of S1 is (hour).

[0207]

[0208]

[0209] Invention examples D1 to D22 satisfying the scope of the present invention showed good Cu surface enrichment degree and average crystal grain size, bu...

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Abstract

The objective of the present invention is to provide a steel member and a steel sheet that have high tensile strength and toughness, and also have excellent hydrogen embrittlement resistance in corrosive environments, and to provide methods for producing the same. A steel member according to the present invention is characterized by having a predetermined chemical composition, wherein the maximumCu content at a depth range within 0-30 [mu]m from the surface is at least 1.4 times greater than the Cu content at a depth of 200 [mu]m from the surface.

Description

technical field [0001] The present invention relates to steel members, steel plates and methods for their manufacture. Background technique [0002] In the field of steel sheets for automobiles, against the backdrop of recent environmental regulations and stricter crash safety standards, the use of steel sheets with high tensile strength is expanding in order to achieve both fuel efficiency and crash safety. However, since the press-formability of steel sheets decreases with increasing strength, it is gradually becoming difficult to manufacture products with complex shapes. [0003] Specifically, since the ductility of the steel sheet decreases with the increase in strength, there is a problem of breakage of highly processed parts. In addition, problems such as springback, wall warpage, and deterioration of dimensional accuracy due to residual stress after processing also arise. Therefore, it is not easy to press-form a steel plate having a high strength, especially a tens...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C21D1/18C21D9/00C21D9/46C22C38/60
CPCC21D1/18C22C38/60C21D6/005C21D6/008C21D1/26C21D1/673C21D2211/008C21D9/48C21D8/0426C21D8/0447C21D8/0463C21D8/0473C21D9/46C23G1/081C23G1/08C25D5/48C22C38/005C22C38/02C22C38/04C22C38/08C22C38/12C22C38/14C22C38/16C22C38/20C22C38/22C22C38/24C22C38/26C22C38/28C22C38/32C22C38/38C22C38/34C21D8/005C21D9/0068C21D8/0226C21D8/0273C21D8/0263C21D8/0205C21D8/0405C21D8/0247C22C38/58C22C38/50C22C38/54C22C38/42C22C38/44C22C38/46C22C38/48B21C47/02C22C38/002C22C38/008C22C38/06
Inventor 田畑进一郎楠见和久匹田和夫入川秀昭
Owner NIPPON STEEL CORP
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