4. Stress corrosion

Nickel alloys have often been considered immune to stress corrosion and specified as substitutes for stainless steels. However, the emergence of new intermediate alloys between stainless steels and the most alloyed nickel alloys, and their use at increasingly high temperatures, are leading some of these alloys to suffer stress corrosion failure. This phenomenon is always associated with an incubation period, ranging from a few minutes to several years, during which no damage is really visible.

Several types of environment are likely to generate stress cracking in nickel alloys:

• hot halogenated media ;

• high-temperature water ;

• hot caustic environments;

• molten metals ;

• solutions containing...