Effect of surface mechanical attrition treatment (SMAT) on pack boronizing of AISI 304 stainless steel

The influence of surface mechanical attrition treatment (SMAT) on pack boronizing of AISI 304 stainless steel (304 SS) is addressed. SMAT of 304 SS was performed using 8 mm Ø 316L stainless steel balls for 60 min. Untreated and SMATed 304 SS samples were pack boronized by single stage (at 1223 K for 1, 3 5 and 7 h) and duplex (973 K for 1 h and 1223 K for 1 h) treatments. SMATed 304 SS increased the kinetics of boron diffusion, enabled the formation of a higher volume fraction of alloy borides and increased the hardness of the borided layer. Duplex treatment increased the case depth than the single stage treatment. The findings of this study suggest that SMAT can be used as an effective pretreatment for boronizing of 304 SS.