Laser surface melting of 304 stainless steel for pitting corrosion resistance improvement

Abstract

Laser surface melting has been conducted on a 304 stainless steel (SS) with the aim of enhancing pitting corrosion resistance of the material. This process involves rapid melting of the material’s surface followed by rapid solidification to refine the microstructure. This includes the dissolution of inclusions such as MnS, FeS, Cr and other minor constituents. The microstructures as a result of laser treatment were observed by means of optical microscope and also confirmed by the XRD. The glow discharge optical emission spectroscopy (GDOES) was utilized for chemical analysis. Changes in hardness were observed by using a Vickers microhardness tester. Pitting corrosion tests on laser treated and untreated samples were conducted according to ASTM G48-92 to evaluate mass loss and pitting morphology. Laser surface melting improved the pitting corrosion resistance of this material in a chloride containing environment.