Abstract. The 304 stainless steel (SS) type is widely used in oil and gas operations due to its excellent corrosion resistance. However, the presence of the line sand particles and H2S gas contained in crude oil could lead the erosion and abrasion in steel. In this study, cold rolled treatments were conducted to the 304 SS in order to increase the wear resistance of the steel. The cold work has resulted in thickness reduction to 20%, 40% and 60% of the original. Various micro structural characterizations were used to analyze the effect of deformation. The hardness characterization showed that the initial hardness value increased from 145 HVC to 395 HVC as the level of defonnation increase. Further, the wear resistance increased with the defonnation rate from 0% to 40% and subsequently decreased from 40% to 60% defonnation rate. Microstmctural characterization shows that the boundary change to coincide by 56 pm, 49 pm, 45 pm, and 43 pm width and the grain go to flatten and being folded like needles. The effect of defonnation on the grain morphology and structure was also studied by optical metallography and X-Ray Diffraction. It is shown that the defonnation by means of a cold rolled process has transfonned the austenite stmcture into martensitic structure.