Characterization of Microstructure and Mechanical Properties of Resistance Spot Welded DP600 Steel

Abstract

Abstract:Resistance spot welding (RSW) as a predominant welding technique used for joining steels in automotive applications needs to be studied carefully in order to improve the mechanical properties of the spot welds. The objectives of the present work are to characterize the resistance spot weldment of DP600 sheet steels. The mechanical properties of the welded joints were evaluated using tensile-shear and cross-tensile tests. The time-temperature evolution during the welding cycle was measured. The microstructures observed in different sites of the welds were correlated to thermal history recorded by thermocouples in the corresponding areas. It was found that cracks initiated in the periphery region of weld nuggets with a martensitic microstructure and a pull-out failure mode was observed. It was also concluded that tempering during RSW was the main reason for hardness decrease in HAZ. OPEN ACCESSMetals 2015, 5 1705

Microstructural analysis of weld nugget properties on resistance spot-welded advance high strength dual phase (α+α/) steel joints

“…The TSFL, CTSFL and hardness value of the joints recorded 21.3 kN, 18.3 kN and 584 Hv for the optimized welding conditions. The high hardness observation was with severe cooling rate associated with the process accounting for the formation martensite in the nugget zone than in nearer zones which again in turn attributed for the pull out and tear type failure of around the joints [17]. Due to severe cooling rate of the process lath/plate martensite was characterized in the nugget zone by optical micrograph which was also found in agreement with SEM indicating twinned martensite phases.…”

Effects of Pulsed Nd:YAG Laser Welding Parameters on Penetration and Microstructure Characterization of a DP1000 Steel Butt Joint

“…Meanwhile, the application of DP steels unavoidably involves welding in the manufacturing process and the properties of welded joints due to the integrity and safety requirements. Although such traditional welding methods as resistance spot welding (RSW) [5], tungsten inert gas welding (TIG) [6], metal inert-gas welding (MIG) [7], and gas arc [8,9] have been widely used, the advantages of laser welding are also well known: energy efficiency, slight heat-affected zone, little heat input per unit volume, and deep penetration [10]. The chief limitation, i.e., cost per watt, is swiftly falling with new advances in laser technology [11].…”

Connection Status Research of the Resistance Spot Welding Joint Based on a Rectangular Terminal Electrode

“…As an important connection method, resistance spot welding (RSW) has the characteristics of energy concentration, small deformation without additional welding materials, high production efficiency, and easy-to-achieve automatic control [1]. It is widely used in the production of automobiles and railways vehicles [2][3][4][5][6].…”