Effect of Deformation Temperature on Hydrogen Embrittlement in Low-Carbon Martensitic Steel

This study investigated the effect of deformation temperature on the hydrogen embrittlement behavior in a low-carbon martensitic steel. Tensile strength and total elongation of the hydrogen-charged specimens significantly decreased with increasing the deformation temperature from -100°C to 25°C. Fracture behavior also changed greatly with the deformation temperature. When the deformation temperature was low (-100°C), the hydrogen-charged specimen exhibited cleavage fracture within prior austenite grains. On the other hand, at the higher temperature (25°C), intergranular fracture at prior austenite grain boundaries mainly occurred. This was presumably because deformation at the lower temperature suppressed hydrogen accumulation at prior austenite grain boundaries, which led to the fracture inside prior austenite grains and the lower hydrogen embrittlement sensitivity.