Laser peening process of 16MnR steel and effect on stress corrosion property of welded structure

Abstract

The laser peening test carried out on the base material 16MnR steel to obtain the optimized process parameters. The residual stress distribution and stress corrosion resistance of the joint before and after laser-MAG hybrid welding were analyzed.The results show that the maximum plastic deformation layer of 475 μm thick and compressive stress distribution of -593 MPa can be introduced on the surface of 16MnR steel plate after laser peening treatment. By performing the optimized laser shock process, the residual tensile stress distribution on the welded joint surface can be effectively reduced.The slow strain rate stress corrosion tests were carried out on the joint samples before and after laser peening treatment under the condition of 3.5%NaCl(mass fraction). The results show that the stress corrosion sensitivity index ISSRT of the 16MnR steel welded joints before and after laser peening are 0.106 and 0.104, respectively. The ISSRT index of the welded joint samples decreases after the impact treatment, which indicates that the stress corrosion resistance of the welded joints increases.

Keywords

• laser peening treatment
• laser-mag hybrid welding
• weld joint
• residual stress
• stress co-rrosion resistance