Comparison Research on Mechanical Properties of Stainless Steel after Laser Peened and Ultrasonically Peened

Abstract

The mechanical properties of 1Cr11Ni2W2MoV stainless steel after laser peening (LP) and ultrasonic shot peening (USP) were examined and compared. The stainless steel specimens were treated with the two different surface processing techniques. X-ray diffractometry (XRD), scanning electron microscope (SEM), microhardness tester were used to investigate microstructure and mechanical properties. Vibration fatigue tests of untreated, LPed and USPed samples were also conducted. The results indicated that LP treatment can improved the fatigue life of 1Cr11Ni2W2MoV stainless steel more effectively. The increases of the compressive residual stress depth and microhardness in surface layer after LP were greater than that of USP. The SEM studies showed that USP treatment had an advantage in microstructure refinement. The compressive residual stresses make great contributions to the superiority of LP in the improvement of fatigue life of 1Cr11Ni2W2MoV stainless steel to USP.