Research Of The Correlation Between Plasma Characteristics And Welding Quality Of Laser-arc Hybrid Welding

The high nitrogen austenitic stainless steel was used as the research material.The plasma shape,the plasma emission spectrum,the electric signal,the welding temperature field and other information were real-time acquired by using the high speed camera,the spectrum acquisition system,the Hannover quality analyzer and the thermal imaging equipment during laser-arc hybrid welding process.The effect of different welding method,arc source distance,pulse frequency,welding current and laser pulse time on the plasma morphology,plasma emission spectroscopy,plasma electron temperature and density was studied.The two conducting channel of arc shape during the laser-arc hybrid welding process was obtained,and the mechanism was also clarified.The correlation between the electron temperature and density with the weld penetration was obtained.The correlation between plasma emission spectrum and weld elements was obtained.The influence of different welding method,distance of heat source,frequency of welding current,welding current and time of laser pulse on welding temperature field was studied by the thermal imaging system.The Matlab software was used to realize the three-dimensional conversion of two dimensional temperature field.Through the analysis of welding temperature field,the relationship between the temperature field distribution and the cooling mode of high nitrogen steel was obtained.And it can be used to solve the nitrogen porosity during the welding.The relationship between temperature field and weld width was also studied.