Title: The influence of deformation history on microstructure and microhardness during the hot stamping process of boron steel B1500HS

Authors: Bingtao Tang; Qiaoling Wang; Zhaoqing Wang; Wei Zheng

Addresses: Institute of Engineering Mechanics, Shandong Jianzhu University, Fengming Rd, Lingang Development Zone, Jinan, 250101, Shandong, China ' Institute of Engineering Mechanics, Shandong Jianzhu University, Fengming Rd, Lingang Development Zone, Jinan, 250101, Shandong, China ' Institute of Engineering Mechanics, Shandong Jianzhu University, Fengming Rd, Lingang Development Zone, Jinan, 250101, Shandong, China ' Institute of Engineering Mechanics, Shandong Jianzhu University, Fengming Rd, Lingang Development Zone, Jinan, 250101, Shandong, China

Abstract: To meet the requirements of energy saving and vehicle security, a novel hot stamping process named tailored tempering can be used to manufacture components with functional optimised mechanical properties. It is essential to know the transformation kinetics of the quenchable ultra-high strength steels and how it is influenced by related process parameters. The influence of deformation history on metallographic and microhardness of boron steel B1500HS is investigated. It can be seen that the true stain exerts a negative influence on actual cooling rate. With the development of true stain, the martensite transformation temperature goes down. The higher strain rate leads to a smaller value of microhardness, while the higher true stain can cause a shift of the position of the 'nose' in the TTT-diagram. The results considering the influence of the transformation kinetics by different process parameters can help to investigate the deformation kinetics and transformation behaviour of boron steels.

Keywords: boron steel; hot stamping; quenching; phase transformation; deformation; microstructure; microhardness; energy saving; vehicle security; tailored tempering; transformation kinetics; strain rate.

DOI: 10.1504/IJMPT.2013.058935

International Journal of Materials and Product Technology, 2013 Vol.46 No.4, pp.255 - 268

Received: 21 Dec 2012
Accepted: 30 Sep 2013
Published online: 21 Jun 2014 *

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