DEVELOPMENT OF PRESS HARDENING STEEL WITH HIGH RESISTANCE TO HYDROGEN EMBRITTLEMENT
Press hardening has become the state-of-art technology in the car body manufacturing to enhance safety standard and to reduce CO2 emission of new vehicles.However the delayed cracking due to hydrogen embrittlement remains to be a critical issue.Generally press hardening steel is susceptible to hydrogen embrittlement due to ultra-high strength and martensitic microstructure.The hydrogen charging tests clearly demonstrate that only a few ppm of diffusible hydrogen is sufficient to cause such embrittlement.Currently the hydrogen embrittlement cannot be detected in the press hardened components and the embitteled components could collapse in the crash situation with fatal consequences arisen through dramatic loss in both strength and ductility.This paper introduces a new metallurgical solution to increase the resistance to hydrogen embrittlement of conventional press hardening steel based on 22MnB5 by Nb microalloying.In the hydrogen embrittlement and permeation tests the impact of Nb microalloying on the hydrogen embrittlement behavior was investigated under different hydrogen charging conditions and constant load.The test results revealed that Nb addition increases the resistance to hydrogen embrittlement due to reduced hydrogen diffusivity.The focus of this paper is to investigate the precipitation behavior of microalloying elements by using TEM and STEM and to find out the mechanisms leading to higher performance against hydrogen embrittlement of Nb alloyed steels.
PHS Hydrogen embrittlement Hydrogen trapping and Nb Microalloying
Jian Bian Hardy Mohrbacher Hongzhou Lu Wenjun Wang
Niobium Tech Asia,068898 Singapore NiobelCon bvba,2970 Schilde,Belgium CITIC Metal,100004 Beijing,China
国内会议
杭州
英文
571-576
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）