Formability of C-Si-Mn-Al-Nb-Mo ultra high-strength TRIP-aided sheet steels

被引：34

作者：

Sugimoto, Koh-ichi

Murata, Muneo

Muramats, Toshiki

Mukai, Yoichi

机构：

[1] Shinshu Univ, Fac Engn, Nagano 3808553, Japan

[2] Shinshu Univ, Grad Sch Sci & Technol, Nagano 3808553, Japan

[3] Kobe Steel Ltd, Res & Dev Labs, Kakogawa, Hyogo 6750023, Japan

来源：

ISIJ INTERNATIONAL | 2007年 / 47卷 / 09期

关键词：

ultra high-strength steel; TRIP-aided steel; retained austenite; formability; aluminum; niobium; galvanization;

D O I：

10.2355/isijinternational.47.1357

中图分类号：

TF [冶金工业];

学科分类号：

0806 ;

摘要：

Formable 980-1470 MPa grade ultra high-strength TRIP-aided sheet steels with bainitic ferrite matrix (TBF steels) have been developed for cold forming of automotive applications. Complex additions of 1.0%Al-0.05%Nb-0.2%Mo to 0.2%C-1.5%Si-1.5%Mn base steel increased both the volume fraction and carbon concentration of retained austenite films of the TBF steel, with refining of microstructure. Extremely much retained austenite was realized in the TBF steel austempered at 450-500 degrees C, corresponding to hot-dip galvanization just after annealing. Good combinations of strength and elongation and strength and stretch-flangeability were achieved when the TBF steel was austempered at 450-500 degrees C and 425-475 degrees C, respectively. These good combinations were caused by fine lath structure and a large amount of metastable retained austenite film. It is noteworthy that the TBF steel exhibited an excellent combination of total elongation and stretch-flangeability when austempered at 325-350 degrees C lower than M-s.

引用

页码：1357 / 1362

页数：6

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