Achieving Stress Relief in Martensitic Stainless Steel Via High-Density Pulsed Electric Current Treatment

This study examined the effect of high-density pulsed electric current (HDPEC) treatment on the residual stress relief of martensitic stainless steel SCS6. The findings indicate that applying HDPEC at 100 A/mm² for 370 ms, or equivalent current conditions at a maximum temperature of approximately 735 °C, can nearly eliminate surface residual stresses. Moreover, this treatment resulted in a 7 pct increase in strength without deteriorating the ductility. X-ray diffraction and electron backscatter diffraction analysis found that defects (i.e., dislocations) within the grains were remarkably removed, which was the main reason for the residual stress removal. This study demonstrates the feasibility of HDPEC in eliminating residual stresses of martensitic stainless steels, presenting a promising alternative to traditional heat treatment. In addition, this method introduces possibilities for localized non-destructive treatments on substantial components, enabling rapid and straightforward repairs.

Graphical abstract