Analysis of Pockmarks Formed on the Surface of 20Cr13 Martensitic Stainless Steel

The surface defects of martensitic stainless-steel table knives were analyzed.The macro-morphology and characteristic of pockmark defects on the surface of martensitic stainless steel were described,and the micro-morphology and component were analyzed by scanning electronic microscopy and energy dispersive spectrometer.The results show that the micromorphology of pockmark defect are various hole,pit and rough.Enough oxygen elements enrich at edge of hole defects,which means there are a lot of oxide scale at edge of hole defects.Silicate inclusions exist in in the pit defects,which accelerates pitting and crevice corrosion and promoted the formation of hole defects.Rough defects are composed of surface scratches,whose scratches are nearly vertical to each other and their direction is consistent with the rubbing direction.So,it can be concluded that avoiding thicker oxide scale and inclusions can prevent pockmark defects on the surface of 20Cr13 martensitic stainless steel.