EFFECTS OF AIR-BLAST PRESSURE AND EXPOSURE TIME ON THE SHOT-PEENING PROCESS

Shot peening was carried out on 6061-T651 aluminium alloy. The effects of two main peening parameters, i.e. the air-blast pressure and the exposure time, on the depth of the plastic zone and on the residual stress of shot-peened plates were investigated and analysed, the experimental data showing that the depth to which yielding occurs is affected by the air-blast pressure as a power law, and that there is an exponential relationship between the depth to which yielding occurs and the exposure time. For a given pressure the depth of yielding approached a limiting value after a certain exposure time. An empirical equation for the relationship of the depth of yielding with the pressure and the time has been derived from the test data. Further, it is found that the maximum residual stress within the shot-peened plate is determined solely by the depth of yielding, according to a simple equation. These two equations are convenient for industrial use.