Deflection behaviour of corrosion crack growth in the heat affected zone of CrNiMoV steel welded joint

Stress corrosion cracking (SCC) growth tests in heat affected zone (HAZ) of 25Cr2Ni2MoV steel welded joint were conducted in 3.5 wt.% NaCl solution at 180 °C. The deflection of SCC towards the hard side of HAZ was observed interestingly, which was ascribed to the combined effect of the graded mechanical and electrochemical properties in HAZ. In addition, the initiation of SCC deflection was related to the crack-tip in-plane constraint. Through the specimen thickness, higher crack-tip out-of-plane constraint on the mid-thickness plane caused a preferential SCC deflection compared to that on the surface.