Equivalence in evaluating hydrogen-assisted fracture strength of slow strain rate tensile and constant load tensile for three precipitation-hardened martensitic stainless steels: Effect of large-sized particles

This study investigated the equivalence in evaluating hydrogen-assisted fracture strength undergoing slow strain rate tensile (SSRT) and constant load tensile (CLT) for three precipitation-hardened martensitic stainless steels containing second-phase particles of different sizes. For both PH13-8Mo and 17-4PH with nano-sized precipitates, the fracture strength was higher for SSRT than for CLT. However, for 15-6PH with both nano-sized precipitates and large-sized carbides, cracks at the larger-sized carbide/matrix interface led to the lower fracture strength for SSRT. Furthermore, we concluded that the hydrogen-assisted threshold fracture strength of CLT could be estimated by using SSRT if no large-sized particles were in high-strength steels.

Automated summary

This study examines the equality in assessing the strength of hydrogen-assisted fractures using slow strain rate tensile (SSRT) and constant load tensile (CLT) methods for three precipitation-hardened martensitic stainless steels with different sized second-phase particles. SSRT showed higher fracture strength than CLT for PH13-8Mo and 17-4PH with nano-sized precipitates. However, for 15-6PH with both nano-sized precipitates and large-sized carbides, cracks at the larger-sized carbide/matrix interface resulted in lower fracture strength for SSRT. Additionally, we conclude that the hydrogen-assisted threshold fracture strength of CLT can be estimated by using SSRT when there are no large-sized particles present in high-strength steels.