Effect of Shot Strip Interval and Shot Times on Laser Shot Peen-Forming with Repetition Laser Pulse

Laser shot peen-forming of sheet metal(or LasershotSM Peening) is a new plastic forming technique for metallic materials, which uses high-power pulsed laser replacing the tiny balls to peen the surface of sheet metal. When the pressure of shock waves induced by laser impresses an inhomogeneous residual stresses distribution in a given depth on the surface of sheet, it responds to the stress by elongating at the peened surface and effectively bending the sheet. In order to investigate the mechanism of laser shot peen-forming, the narrow strip peen-forming experimental of aluminum alloy 6061-T6 was carried out by using a pulsed Nd:glass laser with 0.5Hz repetition-rate. Here, under some given laser energy, laser pulse width, laser beam diameter and pulse repetition frequency and so on, the influence of shot strip interval and shot times on surface residual stresses and the deformation of the sheet is analyzed. The results show that the bending forming of the sheet metal can be found, and the peened surface of sheet metal becomes convex. That the bending increases with shot strip interval increase is not obvious, but it increases with the shot times increase in a proper range of shot times. Besides, because laser shot peen-forming generates compressive residual stresses on the surface, it offers many desirable characteristics in shaped metals and is a valuable technique for producing components for a range of industries.