Susceptibility to Underclad Cracking in Relation to Chemical Composition

Heat-affected zone cracking under the weld-overlay-cladding has been investigated for the combination of 22 kinds of ferritic base metals and electrodes including strip electrodes of austenitic and ferritic stainless steels, Inconel and mild steel, and covered electrodes of austenitic and ferritic stainless steels and Inconel. The results indicate that (1) intercrystalline cracks form on stress relieving under the overlap area of the cladding beads, (2) the susceptibility to cracking depends markedly on the chemical composition of the base metal, and the following equation predicts cracking tendency, ΔG = [Cr] + 3.3 [Mo] + 8.1 [V] − 2, and (3) cracking is avoided or decreased by using cladding material which is similar in thermal expansion coefficient to base metal.