Determination of potency factor of cobalt for estimation of nickel equivalent in 16Cr–2Ni martensitic stainless steel

Abstract

Cobalt is considered to be a potential substitute for nickel in 16Cr–2Ni martensitic stainless steel. However, the percentage of cobalt that can substitute 1% of nickel remains to be determined. A computer program was developed for accurate prediction of δ ferrite content in Schaeffler type diagrams. The δ ferrite content in the steels was measured by metallography and estimated using the computation technique for various Schaeffler type diagrams. The percentage error in the experimentally measured and computed δ ferrite contents was ±1·0%. From the present study, the potency factor of cobalt was computed to be 0·64 that of nickel in the estimation of nickel equivalent.