The influence of residual stresses on laser beam welding processes of aluminium sheets

Abstract

Forming processes may lead to residual stresses remaining in the parts. Laser beam welding leads to a local release of the present stresses, which finally results into strain rates and causes the formation of hot cracks. The relation between the acting stresses and the emerging strain rates was investigated experimentally by means of high-speed digital image correlation during welding of aluminium sheets. In the paper an analytical model is presented which describes the influence of the acting stresses on the emerging strain rates and enables the optimization of the process parameters with regard to a prevention of hot crack formation.