Statistical analysis of process parameters to eliminate hot cracking of fiber laser welded aluminum alloy

• A mathematical model for predicting hot cracking rate is proposed using RSM.
• The effects of process parameters on hot cracking rate were studied individually and interactively.
• Distance from welding center to free edge influenced the hot cracking rate most significantly.
• Economic and efficient welds could be achieved using the welding parameters obtained from the numerical optimization.

This paper investigates hot cracking rate in Al fiber laser welding under various process conditions and performs corresponding process optimization. First, effects of welding process parameters such as distance between welding center line and its closest trim edge, laser power and welding speed on hot cracking rate were investigated experimentally with response surface methodology (RSM). The hot cracking rate in the paper is defined as ratio of hot cracking length over the total weld seam length. Based on the experimental results following Box–Behnken design, a prediction model for the hot cracking rate was developed using a second order polynomial function considering only two factor interaction. The initial prediction result indicated that the established model could predict the hot cracking rate adequately within the range of welding parameters being used. The model was then used to optimize welding parameters to achieve cracking-free welds.