Hydrogen absorption and embrittlement of ultra-high strength aluminized press hardening steel

The use of press hardening steel (PHS) in structural safety-related parts has experienced a rapid growth in the automotive industry, due to increased passenger safety standards, which require an improved vehicle intrusion resistance. Very small concentrations of diffusible hydrogen in ultra-high strength PHS deteriorate their mechanical properties. The focus of the present study was the analysis of the diffusible hydrogen uptake during the hot press forming process of the aluminized PHS and its impact on the mechanical properties of PHS. The effect of the paint baking on the properties of aluminized PHS was also evaluated by mechanical testing and hydrogen thermal desorption analysis. A mechanism for the hydrogen absorption of aluminized PHS was proposed.