Theoretical Analysis of Susceptibility of Ferritic Stainless Steel to Intergranular Corrosion Caused by Welding(Materials, Metallurgy & Weldability)
The carbide precipitation and the susceptibility to intergranular corrosion in ferritic stainless steels were studied theoretically. The thermodynamic data by many references are formulated and the carbide precipitation at the grain boundary was calculated by using a local equilibrium model. Ferritic stainless steel (17Cr-O.01C) becomes susceptible 10^<-5> times more quickly than austenitic one (18Cr-9Ni-0.03C). The phase diagrams for Fe-Cr-C steels on the extremely low-C side were calculated for 1173K to 1473K. Using these diagrams, a strange phenomenon that lower the C content of ferritic stainless steel (i.e. 17Cr-0.07C to 0.03C), the more susceptible it becomes could be explained. It is also showed that the cause of corrosion depends on whether austenitic phase is created or not in the steel at the time of welding.
- Transactions of JWRI
Transactions of JWRI 16 (1), 131-137, 1987-06