Ferritic stainless steels are generally resistant to chlorine SCC but may suffer which type of cracking in hot concentrated caustic?

• A. Intergranular cracking
• B. Environmental cracking
• C. Transgranular cracking
• D. No cracking

Answer: (B)

Environmental cracking is the type of failure at play here. When ferritic stainless steels are under tensile stress in hot, highly concentrated caustic solutions, the caustic environment assaults the protective films and promotes cracking together with the applied stress. This isn’t about the metal’s susceptibility to chloride SCC; it’s about the aggressive alkaline environment enabling crack initiation and growth. The result is cracking driven by the environment itself, which is why this scenario is described as environmental cracking. Intergranular or transgranular paths can occur in different contexts, but the defining factor in hot concentrated caustic is the environmental assistance that leads to cracking.