Effect of electrode force on tensile shear and nugget size of austenitic stainless steel grade 304 welds using resistance spot welding

摘要

This research was to effect of electrode force on the tensile shear and nugget size of the resistance spot welding. The specimen was austenitic stainless steel 304 grade sheet metal 1.2 mm thickness. The electrode force are 1, 1.5, 2.0, 2.5, and 3.0 kN apply to the specimen. The replications in each treatment are 20 follow JIS Z 3136:1999 and JIS Z 3139:1978. Factor control, welding current 7 kA, time current flow 7 cycle and electrode tip diameter 6 mm. The welded specimens were tested by tensile shear testing according to JIS Z 3136: 1999, macro structure testing according to JIS Z 3139: 1978 and analysis results by using One-way ANOVA. The result showed that electrode force had affected on tensile shear and nugget size at 95% confidential (P value ＞ 0.05). The low force induced the gab between specimen increasing then the current flow difficult to pass and both of gab between specimen and nugget seize had increase (Q＝I~2Rt). When the resistance increased so that fusion zone will have a high heating. It had affected to nugget size, heat affected zone and mechanical properties decreasing. The electrode forces are complete 2.5 kN. Tensile shear 9.21 kN and nugget size 5.82 mm. The data can be applied to be used as process monitoring of resistance spot weld quality.