Analysis And Research Of Shot Peening Coverage

Coverage is playing a very important role in the shot peening process, but here is very less analysis and research in the whole field of shot peening. Actually, coverage is a key parameter of shot peening. Different coverage value shall cause part have different surface topography, surface roughness and surface residual stress distribution. This article explain the coverage changing laws by each individual element such as peening angle, shot size, peening distance, shot flow, part-self, shot media etc.) via experiment.1. Shot angle is an important factor that affects the shot peening coverage. Keep other conditions unchanged, the shot angle is linear with the time to achieve the target coverage. Vertical shot can quickly get the target coverage,need more long time to get the target coverage when the shot angle become small and small.2. Shot distance is an important factor that affects the shot peening coverage. Keep other conditions unchanged, the shot distance is linear with the time to achieve the target coverage. It`s easy to get the target coverage with close range when shot peening a very small area.3. Shot size is an important factor that affects the shot peening coverage. Keep other conditions unchanged, the shot size is linear with the time to achieve the target coverage. Compared small size, big size shot is hard to get the target coverage.4. The hardness of part is an important factor that affects the shot peening coverage. Keep other conditions unchanged, low hardness part can easy to get the target coverage compared with the high hardness part.5. Shot flow is an important factor that affects the shot peening coverage. Keep other conditions unchanged, double the flow double the cratering rate.Results of experiment for shot peening Ni-Cr-Mo Low Alloy Steel with different coverage shows that the shot peening coverage of at least 100% is not be necessary to achieve uniform surface compression and hence improved fatigue performance in some metals; Results of experiment for shot peening Ti-64 High temperature titanium alloy with different coverage shows that higher coverage can not get the better shot peening effect even if request >100% coverage some time; Results of experiment for shot peening 20 Cr Mo H Alloy steel gear with different coverage shows that some of existing coverage accept criteria used in industry is not real standard which can be 100% trusted,adopt low coverage also can meet or exceed the expected effect some time.All of shot angle,shot distance, shot size, part-self, and shot flow are the important factors to effect the shot peening coverage. Different part with different material have their most suitable shot peeing coverage, select and control the coverage well lead to get the best effect of shot peening.