Transcrystalline stress corrosion cracking is induced in which grades of stainless steel by chlorides especially, and by hot concentrated caustic?

• A. Martensitic
• B. Ferritic
• C. Austenitic
• D. Precipitation Hardened

Answer: (C)

Transcrystalline (transgranular) cracking in stainless steels is most associated with the austenitic grades. When these alloys—those with the face-centered cubic structure and higher nickel content—are exposed to chlorides, the protective chromium oxide film can break down at stressed regions. Chloride ions concentrate at flaws and initiate cracking that travels through the grains themselves rather than along grain boundaries, producing transgranular cracking. Hot concentrated caustic similarly promotes cracking in these same austenitic alloys by aggressive attack and hydrogen-related embrittlement, again tending to propagate across grains. The other stainless steel families are less prone to this transgranular chloride- and caustic-induced cracking under typical conditions, so the austenitic group is the most susceptible and best explains this failure mode.