ANALYSIS OF DOUBLE RESISTANCE SPOT WELDING'S FAILURE IN HIGH STRENGTH LOW ALLOY STEEL

High strength low alloy steel (HSLA DOCOL 500 LA) is utilized in the automotive structure because of its superior qualities such as good fatigue resistance, a high strength-to-weight ratio, assisting reducing weight vehicle, increasing fuel efficiency and lower CO2 emissions. Resistance Spot Welding (RSW) most welding technique that used to join automobile parts together. This study investigated RSW process for high-strength steel. By utilizing Taguchi approach, optimization double spot nuggets with principal parameters current, time, electrode force was carried out. The values optimum were 8800Amp time 30 cycles 2560 N force. Mechanical microstructure tests out failure modes while test achieved obtain endurance limit it at maximum load 1500 during two types happened: full pull-out cracks around nugget zone.