Stress Corrosion Cracking Behavior of Two Stainless Steel Welded Plates Used in Normal Temperature Water Pool of Nuclear Power Plant in Different Environments

U-shaped bending sample immersion test was used to compare and study the stress corrosion cracking (SCC) behaviors of 304L and S32101 stainless steel welded joints used in normal temperature water pool of nuclear power plant and their substrate in four solutions. The results showed that in boiling MgCl₂ solution, SCC sensitivity of four samples was the highest. 304L welded joint had a mixed intergranular + transgranular SCC, and the SCC sensitivity of 304L stainless steel substrate was higher than that of S32101 stainless steel substrate. In H₂SO₄ solution, 304L stainless steel substrate and 304L welded joint suffered transgranular SCC, and its SCC sensitivities increased with increase of temperature, S32101 stainless steel substrate and S32101 welded joints did not suffer SCC. In simulated service solution, only S32101 welded joint suffered transgranular SCC, and the SCC sensitivity of S32101 stainless sreel welded joint increased with the increase of temperature. In four solutions, the SCC sensitivity of two stainless steel welded joints was higher than that of substrates, and SCC sensitivity of heat-affected zone in welded joint was the highest.