Stress corrosion cracking of low-alloy steels: A review .2. The effect of alloying elements

The literature data on the individual and joint effect of 27 alloying elements (AEs) and impurities on the resistance to stress corrosion cracking (SCC) of iron and low-alloy, including high-strength steels are summarized. Specimens were tested in water solutions of chlorides, nitrates, carbonates, hydrogen sulfide, in alkaline solutions, etc., under various temperatures, pressures, and pH's. Possible mechanisms behind this effect are discussed. The absence of a unified alloying theory and the inconsistency of the available hypotheses are noted. AEs are shown to have a significant effect on the atomic bond strength in ferrite, the uniformity of the element distribution in solid solutions, precipitation anti element segregation at grain boundaries, etc. In most cases, this effect depends on the AE concentration, the presence of other AEs and impurities, corrosive media, electrode potential, test methods, and other factors. By convention, all these factors can be subdivided into those improving the SCC resistance (Al, B, Ca, Ce, Co, Cu, Mo, Nb, Ti, Pd, and La), degrading it (H, N, O, P, S, Sb, Mn, Cr, V, and Ce), acting ambiguously (C, Ni, and Si), and practically neutral (As, Sn, and Zn).(1)