To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its o...To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its optimization and application.This work establishes mathematical model of this novel heat source including electron density based on the gas state equation,Saha equation,and charge conservation equation.This model reveals the laser transmission characteristics in the plasma controlled by temperature and electron density,as well as the electrical and thermal transfer from the composite arc to the base material.The simulated temperature fields,arc pressure distributions,and arc voltages showed good agreement with experimental measurements,with peak pressure errors within 50 Pa and voltage differences within 0.3 V,validating the accuracy of the model.The results showed that the laser increased the arc temperature inside the keyhole,extending the high-temperature zone downwards.The laser has altered the current density distribution at the keyhole edge,decreasing the upper part but increasing the lower part.The trend of heat flux density change is consistent with the current density.There is a high laser absorption zone in the arc between the tungsten electrode and base metal,whose position changes with laser power,thereby improving the position and axial energy distribution of the plasma arc.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.52275302,52375301 and 52322508)the National Key Research and Development Program of China(Grant No.2023YFB3407701)+1 种基金the HaiYou Industrial Experts Programme(Grant No.CYLJ20241901412)the Open Project of the Key Laboratory of Multiscale Laser Manufacturing Technology,Ministry of Education.
文摘To improve the penetration of thick plates,a laser-enhanced plasma arc welding process was developed.However,the current understanding of laser absorption and energy transfer mechanisms is still unclear,limiting its optimization and application.This work establishes mathematical model of this novel heat source including electron density based on the gas state equation,Saha equation,and charge conservation equation.This model reveals the laser transmission characteristics in the plasma controlled by temperature and electron density,as well as the electrical and thermal transfer from the composite arc to the base material.The simulated temperature fields,arc pressure distributions,and arc voltages showed good agreement with experimental measurements,with peak pressure errors within 50 Pa and voltage differences within 0.3 V,validating the accuracy of the model.The results showed that the laser increased the arc temperature inside the keyhole,extending the high-temperature zone downwards.The laser has altered the current density distribution at the keyhole edge,decreasing the upper part but increasing the lower part.The trend of heat flux density change is consistent with the current density.There is a high laser absorption zone in the arc between the tungsten electrode and base metal,whose position changes with laser power,thereby improving the position and axial energy distribution of the plasma arc.
