Proceedings of the 5th International Conference on Metals & Hydrogen P038

Impact of hydrogen on press-hardened steels

Tobias Schaffner (*) * (1)1 , Valentin Kokotin (1)1 , Cássia Castro Müller (1)1 , Janko Banik (1)1

  • (1) 1

    thyssenkrupp Steel Europe AG, Germany

  • (*) *

    (corresponding author)
    tobias.schaffner@thyssenkrupp.com

Abstract

Press-hardened steels (PHS) play a key role in future-oriented light weight automotive concepts due to their extraordinary high strength and good formability. One of the limiting factors for their widespread use is the possibility of hydrogen embrittlement (HE) caused by hydrogen uptake throughout the whole process chain. In this study, the HE behaviour of various PHS grades was investigated by slow strain rate test (SSRT), permeation measurements and thermal desorption analysis (TDA) to evaluate the general and process related HE susceptibility. Theoretical and experimental investigations were performed on four industrial PHS grades with a tensile strength of above 1500 MPa and 1900 MPa. The results have shown a strong correlation between mechanical properties and hydrogen concentration, whereby the strength class of the material, testing parameters and production steps affect the severity of HE. Surface conditions and type of coating can strongly affect the hydrogen uptake and therefore ease or hinder the HE process.

Keywords

  • press-hardened steels
  • ultra-high strength steels
  • hydrogen embrittlement
  • diffusible hydrogen content
  • slow strain rate test

Introduction




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