DESULFURIZATION OF 316L STAINLESS-STEEL CONTAINING MNS DURING SINTERING

The desulfurization of MnS-added 316L stainless steel compacts which were sintered in hydrogen, argon, vacuum, and dissociated ammonia was investigated. Pure hydrogen reduced the sulfur content by 91% when compacts were sintered at 1200 degrees C for 1hr. This level of sulfur reduction is much higher than reported previously for low alloy iron compacts. The main cause for this difference in sulfur reduction is that nickel in stainless steel has a catalytic effect through the formation of H2S. This desulfurization effect must be considered in selecting the sintering atmosphere for stainless steel compacts to which MnS has been added in order to retain the advantage of enhanced machinability.