Hot stamp molded article and method for producing same

A technology of hot stamping and manufacturing methods, which is applied in the direction of manufacturing tools, furnace types, heat treatment furnaces, etc., can solve problems such as processing performance such as complicate shapes of parts, hole expandability, etc., and achieve good hole expandability

Active Publication Date: 2014-09-10
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, even with these existing technologies, it is difficult to meet the requirements of today's automobiles for further weight reduction, higher strength, complex shape of parts, and hole expandability after hot stamping.

Method used

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  • Hot stamp molded article and method for producing same
  • Hot stamp molded article and method for producing same
  • Hot stamp molded article and method for producing same

Examples

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Embodiment

[0132] After continuous casting of the steel with the composition shown in Table 1 at a casting speed of 1.0 m / min to 2.5 m / min, it is directly or temporarily cooled, and then the slab is heated in a heating furnace according to the conditions in Table 2 according to a conventional method, at a temperature of 910 to 2.5 m / min. Hot rolling was performed at a finish rolling temperature of 930° C. to produce a hot-rolled steel sheet. Then, this hot-rolled steel sheet was coiled at the coiling temperature CT shown in Table 2. Thereafter, pickling is performed to remove scale on the surface of the steel sheet, and the sheet is cold rolled to a thickness of 1.2 to 1.4 mm. At this time, cold rolling was performed so that the value of Formula e became the value shown in Table 2. After cold rolling, annealing was performed at the annealing temperatures shown in Table 3 and Table 4 in a continuous annealing furnace. Hot-dip galvanizing is further performed on a part of the steel sheet...

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Abstract

A hot stamp molded article is characterized in that when the carbon content (mass%), silicon content (mass%) and manganese content (mass%) are expressed as [C], [Si] and [Mn], respectively, a relationship of (5*[Si] + [Mn]) / [C] > 10 holds, and if the metal structure contains martensite at 80% or more by area ratio, and further contains one or more of perlite at 10% or less by area ratio, retained austenite at 5% or less by volume ratio, ferrite at 20% or less by area ratio, and bainite at less than 20% by area ratio, TS lambda, which is the product of the tensile strength (TS) and hole expansion rate (lambda), is at least 50000 MPa.%, and the hardness of the martensite, as measured by a nanoindenter, satisfies H2 / H1 < 1.10 and sigmaHM < 20.

Description

technical field [0001] The present invention relates to a hot-stamped formed body excellent in formability using a cold-rolled steel sheet for hot-stamping and a method for producing the same. The cold-rolled steel sheet of the present invention includes cold-rolled steel sheet, hot-dip galvanized cold-rolled steel sheet, alloyed hot-dip galvanized cold-rolled steel sheet, electro-galvanized cold-rolled steel sheet and aluminized cold-rolled steel sheet. [0002] This application claims priority based on Japanese Patent Application No. 2012-004552 for which it applied in Japan on January 13, 2012, and uses the content here. Background technique [0003] Currently, steel sheets for automobiles are required to improve their crash safety and reduce their weight. Currently, not only steel sheets with a tensile strength of 980 MPa class (980 MPa or more) and 1180 MPa class (1180 MPa or more) but also higher strength steel sheets are required. For example, a steel plate exceedin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00B21B3/00C21D9/46C22C38/58C23C2/02C23C2/06C23C2/12C23C2/26C23C2/28
CPCC21D2211/008C23C2/28C23C2/06C22C38/14C23C2/12C22C38/04C22C38/58C21D9/46C22C38/001C22C38/22C22C38/00C22C38/06C22C38/28C21D8/0263B21B3/00C22C38/005C21D8/0236C22C38/002C22C38/18C22C38/02C21D8/0226C22C38/12C21D1/673C23C2/02C23C2/26C21D8/0284C22C38/16C22C38/08C22C38/32C22C38/38Y10T428/12757Y10T428/12799C23C2/024C23C2/0224
Inventor 野中俊树加藤敏川崎薰友清寿雅
Owner NIPPON STEEL CORP
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