Effect of MnS powder additions on corrosion resistance of sintered 304L stainless steels

Abstract

MnS powder is an additive used to improve the machinability of sintered austenitic stainless steels. The effect of the MnS powder content on the compactability and sinterability of 304L stainless steel powder and the corrosion resistance of the sintered 304L alloys was investigated. Experimental results show that the addition of MnS powder decreases the green density of the 304L compacts. The volume shrinkage ratio and sintered density increase with increasing sintering temperature and decreases with increasing MnS content when less than 0·6 wt-% MnS powder is added, then increases as the MnS content is further increased. The corrosion resistance of the sintered 304L stainless steels is reduced by the addition of the MnS powder. The weight loss rate of the sintered specimens immersed in the 10% FeCl₃ corrosion test solution increases with increasing MnS content. The corrosion resistance is improved with increasing sintering temperature, but the alloys sintered at 1250°C exhibit an abnormally high weight loss rate after the corrosion immersion test.