High-strength cold-rolled steel sheet having excellent workability and collision characteristics and having tensile strength of 980 MPa or more, and method for producing same

A tensile strength, cold-rolled steel plate technology, applied in the direction of manufacturing tools, hot-dip plating process, metal material coating process, etc., can solve the problems of reduced product shape workability, poor ductility and extended flangeability Excellent effect of stretch flangeability

Active Publication Date: 2017-12-01
KOBE STEEL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, if the strength of the steel plate is increased, its ductility and stretch flangeability will deteriorate, resulting in a decrease in the formability of the product.

Method used

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  • High-strength cold-rolled steel sheet having excellent workability and collision characteristics and having tensile strength of 980 MPa or more, and method for producing same
  • High-strength cold-rolled steel sheet having excellent workability and collision characteristics and having tensile strength of 980 MPa or more, and method for producing same
  • High-strength cold-rolled steel sheet having excellent workability and collision characteristics and having tensile strength of 980 MPa or more, and method for producing same

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Embodiment

[0152] Hereinafter, the present invention is described in more detail by enumerating the examples, but the present invention is not limited by the following examples, and certainly can be implemented within the scope of the above-mentioned and following contents, and these are also included in the present invention within the technical range.

[0153] Cold-rolled steel sheets were produced by melting steels containing the components shown in Table 1 below and the balance being iron and unavoidable impurities, followed by hot rolling, cold rolling, and continuous annealing. In Table 1 below, "-" indicates that no element is contained. In Table 1 below, Ar calculated based on the above formula (ii) is shown 3 The temperature of the point and Ac calculated based on the above formula (iii) 3 point temperature. also, figure 1 An example of a heat treatment method by continuous annealing is shown. figure 1 1 in the figure represents the heating process, 2 represents the soaking...

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Abstract

Provided are: a high-strength cold-rolled steel sheet having a tensile strength of 980 MPa or more, having good workability as evaluated by ductility and stretch-flangeability, and having excellent collision characteristics; and a method for producing said steel sheet. In this high-strength cold-rolled steel sheet, the metal structure at a position of 1 4 sheet thickness satisfies (1)-(4) below. (1) The area ratio of ferrite is 0-10%, inclusive, and the balance is a hard phase comprising at least one selected from the group consisting of bainitic ferrite, bainite, and tempered martensite, said hard phase including quenched martensite and retained austenite. (2) The volume ratio V[gamma] of retained austenite is 5-30%, inclusive. (3) The area ratio VMA of an MA structure in which quenched martensite and retained austenite are combined is 3-25%, inclusive, and the average equivalent circle diameter of the MA structure is 2.0 [mu]m or less. (4) The ratio VMA / V[gamma] of the area ratio VMA of the MA structure to the volume ratio V[gamma] of the retained austenite is 0.50-1.50.

Description

technical field [0001] The present invention relates to a high-strength cold-rolled steel sheet having excellent workability and impact properties and a tensile strength of 980 MPa or more, and a method for producing the same. Specifically, the present invention relates to the above-mentioned high-strength cold-rolled steel sheet, a high-strength electro-galvanized steel sheet having an electro-galvanized layer formed on the surface of the high-strength cold-rolled steel sheet, A high-strength hot-dip galvanized steel sheet having a hot-dip galvanized layer, a high-strength alloyed hot-dip galvanized steel sheet having an alloyed hot-dip galvanized layer formed on the surface of the high-strength cold-rolled steel sheet, and combinations of these steel sheets Production method. Background technique [0002] In order to reduce the fuel consumption of automobiles, transport aircraft, etc., it is required to reduce the weight of automobiles, transport aircraft, and the like. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/60C21D8/02C21D9/46
CPCC21D6/005C21D6/008C21D8/0205C21D8/0226C21D8/0273C23C2/40C22C38/002C22C38/005C22C38/08C22C38/12C22C38/14C22C38/20C22C38/34C22C38/38C21D2211/001C21D2211/005C21D2211/008C21D8/0236C21D9/46C22C38/001C22C38/02C22C38/04C22C38/06C23C2/02C23C2/06C23C2/28C23C2/024C23C2/0224
Inventor 村田忠夫二村裕一粕谷康二
Owner KOBE STEEL LTD
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