Research On The Spot Welding Equipment And Spot Welding Technology For The Galvanized Steel Sheet

Galvanized steel has good corrosion resistance,now,it is widely used in theautomotive industry and home appliances.Study on spot welding of galvanized sheet hadbeen particularly important,but,some of domestic spot welding can not guarantee thewelding quality because of the grid voltage.This paper presents a project about research on the spot welding machine of small andintelligent.Including the body product,net voltage compensation system design and Programming ofPLC.For the body product,including make transformer,pneumatic device and control systeminstallation.For network voltage compensation system,conduct the voltage compensationcalculation,according to the dichotomy of calculated work out the conducting angle at a particularvoltage,for the particular data use three order spline interpolation to obtain the relationship betweenpower voltage and conduction angle,The controlling program for PLC,analysis of spot weldingprocess,the program of pneumatic control system were designed,according to net voltage compensationcalculation to conduct the net pressure compensation systems program editing,delivering the programwith a specific data transmission lines into the spot welding machine of PLC.For the small spot welderconduct performance test,the results show that: the power supply voltage fluctuations in the range of380±15%V,the welding current is relatively stable and ensure the welding quality,The small spot welderdevelop very successfully.For the spot welding technology of galvanized sheet,takes0.5mm thickness of galvanized steelsheet as the research object,in the independent development of small spot welder for welding test,underdifferent welding parameters conduct the welding test of galvanized steel sheet,in the tensile testingmachine for shearing tensile test,measuring weld joint shear, use vernier caliper to measure the spotdiameter, using Origin software for curve fitting, analyzed the different welding parameters on jointmechanical properties;microstructure of spot-welding joints were photographed,through metallographicanalysis of welding spots of microscopic features,to understand the different welding parameters onnugget formation effect.