High yield ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expansion properties, and manufacturing method thereof

A technology of hot-dip galvanized steel sheet and manufacturing method, which is applied in chemical instruments and methods, manufacturing tools, hot-dip plating processes, etc., can solve the problems of reduced ductility and hole expandability, etc. Excellent ductility and hole expandability

Active Publication Date: 2013-03-27
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is concern that the ductility and hole expandability will decrease due to the high strength of the steel plate

Method used

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  • High yield ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expansion properties, and manufacturing method thereof
  • High yield ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expansion properties, and manufacturing method thereof
  • High yield ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expansion properties, and manufacturing method thereof

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Embodiment

[0094] The steel having the composition shown in Table 1 and the balance consisting of Fe and unavoidable impurities was smelted in a converter, and a steel slab was produced by a continuous casting method. After heating the obtained steel slab to 1200°C, it was hot rolled at the finish rolling exit temperature shown in Table 2 until the thickness of each plate was 2.3 to 3.2 mm, and coiled at the coiling temperature shown in Table 2. . Next, the obtained hot-rolled sheet was pickled, passed through a continuous hot-dip galvanizing line, annealed under the conditions shown in Table 2, and then hot-dip galvanized, and then subjected to alloying treatment under the conditions shown in Table 2. Thus, a hot-dip galvanized steel sheet (alloyed hot-dip galvanized steel sheet, type of coating in Table 3: GA) was obtained. For a part, a hot-dip galvanized steel sheet (type of coating in Table 3: GI) that was not alloyed was obtained. The hot-dip galvanizing bath uses a zinc bath cont...

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Abstract

Disclosed is a high yield ratio hot-dip galvanized steel sheet with excellent ductility and hole expansion properties and having a tensile strength: TS) of 590 MPa or greater; also disclosed is a manufacturing method thereof. The disclosed high yield ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expansion properties contains, by mass%, C: between 0.04% and 0.13%, Si: between 0.9% and 2.3%, Mn: between 0.8% and 2.4%, P: less than 0.1%, S: .01% or less, Al: between 0.01% and 0.1%, N: 0.008% or less, with the remainder consisting of iron and inevitable impurities. The composition is 94% or more ferrite and 2% or less martensite by area ratio, the average grain size of the ferrite is 10[mu]m or less, the Vickers hardness of the ferrite is 140 or greater, the average grain size of the carbides present on the ferrite grain boundaries is 0.5[mu]m or less, and the aspect ratio of the carbides present on the ferrite grain boundaries is 2.0 or less.

Description

Technical field [0001] The present invention relates to a high-yield-ratio high-strength hot-dip galvanized steel sheet with excellent ductility and hole expandability suitable as a member used in the automotive industry, and a method for manufacturing the same. Background technique [0002] In recent years, due to the increasing awareness of the protection of the global environment, there is a strong demand for improved fuel efficiency to reduce the CO of automobiles 2 Emissions. Along with this, there is an increasingly active trend to reduce the weight of the car body by increasing the strength of the body material to achieve thinning. However, there is a concern that the ductility and hole expandability will decrease due to the increased strength of the steel sheet. Therefore, it is desired to develop a high-strength steel sheet having both high ductility and high hole expandability. In addition, from the viewpoint of ensuring the buckling resistance corresponding to the pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C21D9/46C22C38/06C22C38/58C23C2/02C23C2/06C23C2/28C23C2/40
CPCC21D9/46C21D2211/008C22C38/06C21D6/008C21D6/005C23C2/40C21D2211/005B05D3/0218B05D3/12C22C38/00B32B15/013C22C38/001C22C38/02C22C38/04Y10T428/12965C22C1/02
Inventor 川崎由康中垣内达也金子真次郎长泷康伸福士惠介
Owner JFE STEEL CORP
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