The Study Of Automobile Galvanized Steel Robotic Arc Welding Technology

Since galvanized steel has the characteristic of zinc layer of physical shielding,electrochemical protection and good corrosion resistance,it is widely used in automobile industry.However,the existence of low melting point layer would bring some challenges to the joining of galvanized steel,so it is difficult to solve this engineering problem.In this paper,aimed at welding porosity,crack and slag during arc welding process,we studied the effect of different welding parameters?welding current,velocity and torch tilt angle?,lap gap,various percentage mixes of shielding gas and thickness on the quality of the welded joint.Comparing with the plentiful welding procedure,it can obtain the key affecting factors and optimal procedure parameters.Firstly,build a robot welding platform for galvanized steel,develop the simple welding jigsdepending on galvanized steel welding process characteristics,design robot GMAW welding process test program.Secondly,research on the effect for welding appearance when the galvanized steel welded with various shielding gas mixture.The paper also studied what is the influence mechanism of porosity in the galvanized steel welding joints caused by the various mixture of Ar+CO₂ or Ar+H₂+CO₂ under a certain welding current,welding speed and air flow.Through a lot of welding process test,the study found H₂ in the meltpool has a certain dilution effect for the welding metal,but little effect on porosity reduction;while it's better that shielding gas add a certain volume of O₂ for welding galvanized sheet,but O₂ cannot completely remove the porosity,when O₂ exceeds a certain amount,the arc is difficult to be started and easy to break by explosion.Thirdly,study the effect on welding apparence and joints quality of galvanized steel welding with different fit-up conditions and welding parameters by GMAW.Perform the galvanized steel robot welding process test with different lapping gap?0mm,0.5mm,1mm?,torch angle?35°,45°,55°,65°,80°?,travel angle?60°¹20°?,plate thickness?1mm,2mm?and welding parameters,in order to achieve the ideal welding process range for galvanized steel.Fourthly,for the typical welding joints of auto-body,1.6mm fillet welds of galvanized steel,with DC pulse,CMT and CMT+P welding source,research the influence rule forwelding apparence and joints quality of galvanized steel welding by different welding precesses,on different welding position?uphill,flat,downhill?.In the end,through the systematic research on the process of robot arc welding for galvanized steel sheet,this research found reasonable specified welding parameters for automotive galvanized sheet welding,technical problems can be well solved,provided the reliable welding procedure documents for automobile body manufacturing enterprises.