The Best Penetration of Fusion Welding for Sheet Metal

In metallographic testing, it was found that most components were increased weld penetration immoderately because of lacking the upper limit of weld penetration values in the relating test standards. And most components fractured because base metal for welding were overheat. In order to get different welding body, carbon dioxide gas shielded arc welding was used for welding the different thickness of low carbon steel plate by controling the welding parameters, including welding current, welding voltage, etc. The mechanical properties and microstructures of the weldments were investigated by means of universal tensile testing machine, micro hardness tester and optical microscopy. The effects of weld penetration on tensile strength, hardness, microstructure of weldments were examined and the optimum range of weld penetration values was determined. The results showed that when the penetration values were not only greater than 0.2 mm but also smaller than 0.6 times of the thickness,the weldments had sufficient tensile strength and the fracture failure because of base metal overheat could be avoid. So without tensile test, the weldment could be judged from weld penetration values.