Temperature dependence of sensitization on tensile pre-strained AISI 304 stainless steels

• The degree of sensitization increased with the increasing of strain at low temperature.
• The strain promoted desensitization at higher temperature.
• The reversed transformation of strain-induced α′-martensite in higher temperature decreased sensitization.

With the increase of strain, the degree of sensitization of 304 stainless steels increased and desensitization did not occur in 240 h at 380 °C. Although the stress relaxation appeared, the reversed transformation of strain-induced martensite was scarcely observed. Therefore, strain-induced α′-martensite could lead directly to increase of degree of sensitization. Unlike the sensitization at lower temperature, tensile pre-strain promoted desensitization in higher temperature at 575 °C and 675 °C. The higher the sensitization temperature was, the lower the degree of sensitization was. The higher temperature promoted reversed transformation of strain-induced α′-martensite and facilitated recovery and recrystallization of reversed transformed austenite, which resulted in decreased degree of sensitization.