Formation and Effects of Secondary Phases in Duplex Stainless Steel Weld Metals

Duplex stainless steels were developed in the early thirties in Sweden and in France. The first duplex steels had about 65% of ferrite in the solution annealed condition and the high ferrite content resulted in rather bad mechanical properties in the Heat affected Zone after welding. Secondary phases play an important role in determining the properties of duplex stainless steel. In this paper, a brief discussion is made about the formation and effect of various phases like sigma (σ), cubic (χ), R-, α¹  G-, τ and laves phase along with the acceptance criteria for secondary phases.