Effect of heating process on cold bending ability of 1800 MPa grade hot stamped steel

doi:10.13251/j.issn.0254-6051.2021.04.022

Abstract

Abstract: Effect of holding time in pre-heating process for hot stamping on microstructure and cold bending property of a 1800 MPa grade hot stamped steel was analyzed by means of cold bending test machine, optical microscope and scanning electron microscope. The results show that with the increase of holding time, the prior austenite grains of the hot stamped steel grow up. When the holding time is 5 min, the prior austenite grains are fine and uniform with the average size of about 5 μm. When the holding time reaches 9 min, abnormal coarse grains appear. The cold bending angle is closely related to the prior austenite grain size, i.e., it decreases with grain growth. The maximum cold bending angle is 54.5° when the holding time is 5 min.

Key words: 1800 MPa grade hot stamped steel, prior austenite grain size, hot stamping, holding time in heating, cold bending ability

CLC Number:

TG156

Jin Jiachun, Deng Zongji, Yang Zhen, Li Zitao, Lu Qianqian, Cui Lei, Liu Yonggang, Zhan Hua. Effect of heating process on cold bending ability of 1800 MPa grade hot stamped steel[J]. Heat Treatment of Metals, 2021, 46(4): 126-130.

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