High-strength galvanized steel sheet and method for producing same

A technology of galvanized steel sheet and manufacturing method, applied in the direction of manufacturing tools, chemical instruments and methods, hot-dip galvanizing process, etc., can solve the problem of no galvanized steel sheet, no consideration of tensile flangeability, no consideration of spot weld cracks, etc. problems, to achieve the effect of excellent bendability

Active Publication Date: 2018-09-28
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, stretch flangeability is not considered in Patent Document 2, and there is room for improvement
In addition, there is no opinion on galvanized steel sheets, and spot weld cracks caused by galva

Method used

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  • High-strength galvanized steel sheet and method for producing same
  • High-strength galvanized steel sheet and method for producing same
  • High-strength galvanized steel sheet and method for producing same

Examples

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Embodiment

[0112] Steels having the compositions shown in Table 1 were melted and rolled in a laboratory vacuum melting furnace to produce billets (in Table 1, N is an unavoidable impurity). These billets were heated to 1200° C., and rough rolling and finish rolling were performed to obtain hot-rolled sheets with a thickness of 3.0 mm. The finishing temperature of hot rolling is 900°C, and the coiling temperature is 500°C. Next, after pickling the hot-rolled sheet, a part of it was cold-rolled to 1.4 mm to obtain a cold-rolled sheet (the rolling reduction is shown in Table 2). The obtained hot-rolled sheet and cold-rolled sheet were subjected to annealing. Annealing was performed in a laboratory using a heat treatment and plating treatment apparatus under the conditions shown in Table 2, and alloyed hot-dip galvanized steel sheets 1 to 31 were produced. Galvanized by immersion in a 460 ° C plating solution to form an adhesion of 35 ~ 45g / m 2 The alloying treatment is carried out by ke...

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Abstract

Provided are: a high-strength galvanized steel sheet having exceptional bendability, spot weld crack resistance, stretch-flangeability, and axial crushing stability; and a method for producing the same. This high-strength galvanized steel sheet is provided with a steel sheet and a specific galvanizing layer, the steel sheet having a specific component composition and a steel structure that contains ferrite- and carbide-free bainite in a total area ratio of 25% or less (including 0%), bainite containing tempered martensite and carbide in a total area ratio of 70-97%, martensite and residual austenite in a total area ratio of 3-20%, and residual austenite in an area ratio of 1-5%, the steel structure being configured such that the total area ratio of the ferrite- and carbide-free bainite, the martensite, and the residual austenite is 3-30%, the C level in the residual austenite is 0.10-0.50%, and the average crystal grain size of the carbide-containing bainite and the average crystal grain size of the tempered martensite is 5-20 [mu]m.

Description

technical field [0001] The present invention relates to components suitable for use in automobiles, having flexibility, spot weld crack resistance, stretch flangeability, and axial crush stability (meaning that no cracks or cracks are generated during axial crushing, and stable A high-strength galvanized steel sheet excellent in the property of being crushed into a concertina shape, and a manufacturing method thereof. Background technique [0002] From the viewpoint of improving the collision safety of automobiles, improving fuel consumption, and preventing rust, high rust-proof and high-strength steel sheets used for automotive parts are required. However, strengthening of a material generally leads to a decrease in workability, and therefore, development of a steel sheet that is excellent in workability in addition to strength and rust resistance has been demanded. Furthermore, it is required to have excellent performance as a component after processing. For example, par...

Claims

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Application Information

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IPC IPC(8): C22C38/00C21D9/46C22C38/38C22C38/60C23C2/02C23C2/06C23C2/28C23C2/40
CPCC23C2/02C23C2/06C23C2/28C23C2/40C21D9/46C22C38/38C22C38/60Y02P10/20C22C38/02C22C38/04C22C38/26C22C38/28C22C38/22C22C38/24C22C38/58C22C38/20C22C38/32C22C38/002C22C38/005C22C38/008B32B15/013C21D9/48C21D2211/005C21D2211/001C21D2211/008C21D2211/002C21D8/0236C21D8/0436C21D8/0273C21D8/0473C21D1/25C21D1/19C23C2/022C23C2/0224C23C2/29C23C2/024C21D8/0226C22C38/06C22C38/001C22C38/08C22C38/12C22C38/14C22C38/16C23C18/54
Inventor 长谷川宽船川义正吉富裕美高岛克利
Owner JFE STEEL CORP
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