Analysis and prediction of weld bead volume and hardness in laser welding of low carbon dual phase steel

In this present study, Nd:YAG laser welding of a dual phase steel has been carried out. Due to the importance of weld bead volume and hardness in weld properties such as mechanical and metallurgical behavior, the goal was to develop mathematic models to predict the weld bead volume and hardness of result welds. The independent variables were voltage, frequency, and pulse duration and beam diameter. Polynomial equations for predicting the weld bead volume and hardness were developed and analysis of variance for significance of the models, the test for significance on individual model coefficients and the lack of fit test were performed using design expert software. It was founded that voltage has the main effect on the both weld bead volume and microhardness of result welds and frequency and pulse duration have the next main effects on the responses respectively and analysis of variance showed that developed models are adequate. No significant effect showed by beam diameter due to reciprocal effect. The developed models were checked for the adequacy and accuracy of prediction. Confirmatory tests showed that the models are adequate for prediction of weld bead volume and hardness of result welds.

Keywords:

Laser welding , Dual phase steel , Weld bead volume , Microhardness , Analysis of variance