Static and Impact Strengths of Spot-Welded HSLA and Low Carbon Steel Joints

The static and impact load-carrying capability of resistance spot-welded HSLA and low carbon steel joints as influenced by loading rates, loading modes and welding schedules are presented. Peak load data at five testing speeds spanning between 1.6 × 10⁻⁴ km/h (10⁻⁴ mph) and 24 km/h (15 mph) for bare (1.5 mm; 0.060” gage) and galvanized (1.4 mm; 0.055” gage), 414 MPa (60 ksi)-yield HSLA steel and bare (1.3 mm; 0.050” gage) and galvanized (1.3 mm; 0.050” gage) low carbon steel showed an increase in maximum load with increasing test velocity. The tensile shear configuration exhibited the highest failure loads of the three joints tested, followed by the cross tension and coach peel joints. Results from under-, nominal-, and over-welded specimens suggested that slight over-welding in the expulsion region of the weld lobe could produce welds with similar, if not higher, loads as nominally-welded joints, whereas under-welding generally reduced the weld load-carrying capability.