The fracture of a stainless steel pipe in a hydrogen manufacturing facility prompted a study of stress corrosion cracking of 304L stainless steel and 1 l/4 Cr - l/2 MO low alloy steel in aqueous potassium hydroxide solutions using the slow strain rate technique. Both alloys were found to crack in this environment although the low aIloy steel cracked at less severe temperatures. The cracking of stainless steel was aggravated by hydrogen or carbon monoxide. The potassium hydroxide
environment required higher temperatures to crack the stainless alloy than was noted for aqueous sodium hydroxide. An upper temperature limit was found for the low alloy steel.
Keywords: caustic cracking, stress corrosion cracking, potassium hydroxide, sodium hydroxide, syngas systems, stainless steel, low alloy steel, slow strain rate test