| Abstrakt: |
Laser shock peening is a surface treatment technology, which modifies the residual stress state of metal parts. When forming thin sheet metal parts with thicknesses ≤1 mm, locally varying residual stress states are, according to the literature, the main reason for the scatter in the bent angle. Forming processes, such as bending, are often used to manufacture thin sheet metal. Thin sheets are formed in quantities of several hundreds of millions per year. Even scrap rates that are in the ppm range, caused by the scatter in the bent angle, lead to considerable manufacturing costs. To ensure a robust forming process, it is hypothesized that the laser shock peening process can reproducibly change the residual stress state in thin sheet metal parts in such a way that scatter in the bent angle can substantially be reduced. Annealed and 1 mm thick sheet metal made of X5CrNi18-10 were processed with a nanosecond pulsed fiber laser. The influence of laser peening without coating (LPwC) on the bent angle was investigated using bottom bending with a nominal bending angle of 90°. It was revealed that the standard deviation of the bent angle, i.e., the scatter, is reduced by a factor of 2 from ±0.14° down to ±0.07° compared to the initial sheet state. Hence, the possibility to use LPwC as a pretreatment to decrease the scatter in the bent angle for thin sheets is demonstrated. [ABSTRACT FROM AUTHOR] |
