Gard-Thompson, Trisha, et al. "Why Some High-Hard Steels Fail: Linking Grain Structure to Environmental Toughness in 500HB-600HB Alloys." 14 Nov. 2025. TS - typescript (typed). *
High-Hardness steels in the 500-600 Brinell hardness (HB) range are widely used in defense and industrial applications due to their high strength and abrasion resistance. However, these steels are vulnerable to environmentally accelerated cracking in corrosive or hydrogen-rich environments. Our study reveals significant variability in environmental durability among steels from different manufacturers, even within the same hardness rating. We used an immersed tuning fork test (TFT) to compare the durability of several steels. This novel test approach submerges stressed samples with a ~0.3mm notch in saltwater until crack initiation and failure. Our results showed an over 10X difference in lifetime between the best and worst of the steels within the 500HB class. This study investigates the microstructural factors that may explain those differences