Experimental Study On Surface Peening Technology To 16mnrwelded Joint

Surface treatment is to improve the fatigue life of mechanical parts and the use of effective means of reliability. High-energy shot peening has been achieved in a variety of materials nanostructured surface layer, reaching the surface enhancement effect; water cavitation peening is a recently launched new technology research. It is still not reported.Two kinds of shot peening conditions on the impact of 16MnR welded joints, carried out the study in China and application of great significance.In this paper, 16MnR welded joints on the two shot peening specimen for testing, using optical microscopy, scanning electron microscopy, hardness testing and X-ray diffraction method at different times after the nanocrystalline material morphology, hardness and grain deformation size were analyzed. Water cavitation peening on the residual stress and surface samples for analysis of crude salvation.The results showed that: After peening for 120 minutes, the sample organizations have nanocrystallization, crystallite size to 47 nm. The grains become finer with the shot peening time. Shot sample surface layer of plastic deformation, plastic deformation layer of depth with the increase of treatment duration, since the department of the surface to the center gradually increase up to 120μm. Surface nano-hardness of the sample surface with the increase of treatment duration. After peening for 120 minutes, the base metal, weld and heat affected zone has reached the maximum surface hardness was 380-400 HV, 460 HV and 425 HV.After water cavitation peening ,the surface hardness of the material presented center is very hard, with increasing distance from the center of the surface hardness of a decreasing trend. Surface hardness increase with water cavitation peening time. When the time is too long, severe surface damage. 40min is best. Water cavitation peening 10min to 40min from the base material surface roughness 0.205 to 0.380, increasing more slowly, but the surface roughness of 0.615 shot 50min, 40min for the water blasting one of the best technical parameters of treatment duration.