Effective Range of FSSW Parameters for High Load-Carrying Capacity of Dissimilar Steel A283M-C/Brass CuZn40 Joints

Abstract

In the current study, a 2 mm thick low-carbon steel sheet (A283M—Grade C) was joined with a brass sheet (CuZn40) of 1 mm thickness using friction stir spot welding (FSSW). Different welding parameters including rotational speeds of 1000, 1250, and 1500 rpm, and dwell times of 5, 10, 20, and 30 s were applied to explore the effective range of parameters to have FSSW joints with high load-carrying capacity. The joint quality of the friction stir spot-welded (FSSWed) dissimilar materials was evaluated via visual examination, tensile lap shear test, hardness test, and macro- and microstructural investigation using SEM. Moreover, EDS analysis was applied to examine the mixing at the interfaces of the dissimilar materials. Heat input calculation for the FSSW of steel–brass was found to be linearly proportional with the number of revolutions per spot joint, with maximum heat input obtained of 11 kJ at the number of revolutions of 500. The temperature measurement during FSSW showed agreement with the heat input dependence on the number of revolution. However, at the same revolutions of 500, it was found that the higher rotation speed of 1500 rpm resulted in higher temperature of 583 °C compared to 535 °C at rotation speed of 1000 rpm. This implies the significant effect for the rotation speed in the increase of temperature. The macro investigations of the friction stir spot-welded joints transverse sections showed sound joints at the different investigated parameters with significant joint ligament between the steel and brass. FSSW of steel/brass joints with a number of revolutions ranging between 250 to 500 revolutions per spot at appropriate tool speed range (1000–1500 rpm) produces joints with high load-carrying capacity from 4 kN to 7.5 kN. The hardness showed an increase in the carbon steel (lower sheet) with maximum of 248 HV and an increase of brass hardness at mixed interface between brass and steel with significant reduction in the stir zone hardness. Microstructural investigation of the joint zone showed mechanical mixing between steel and brass with the steel extruded from the lower sheet into the upper brass sheet.

A Novel Friction Stir Deposition Technique to Refill Keyhole of Friction Stir Spot Welded AA6082-T6 Dissimilar Joints of Different Sheet Thicknesses

“…The total heat input energy is the summation of the generated heat input energy at the contact shoulder area and the pin surrounding contact area. The generated heat input energy during the FSSW process depends on the tool design, tool material, friction axial downward force, friction coefficient at the interface between the rotating pin and the surrounded stirring material, applied dwell time, and rotation speed [ 9 , 37 ]. The heat input is generated by converting the mechanical energy from the friction of the rotating tool through the joint thickness during the FSSW thermomechanical process.…”

“…Different spot joining techniques have been used in the automotive industry, such as riveting and resistance spot welding. Recently, to avoid the drawbacks of these spot welding techniques, alternative joining techniques in terms of friction stir welding (FSW) and its derivative friction stir spot welding (FSSW) processes are used for joining similar [ 3 , 4 ] and dissimilar structural materials [ 5 , 6 , 7 , 8 , 9 ] in engineering applications. The FSSW is a solid-state joining technique.…”

Special Issue: Advance in Friction Stir Processed Materials

“…In papers [ 17 , 18 ], the authors focused on selection of the parameters in friction stir spot-welding (FSSW) processes. Ataya et al [ 17 ] joined a low-carbon steel sheet (A283M-Grade C) with a brass sheet (CuZn40) by means of FSSW using different rotational speeds and dwell times to explore the effective range of parameters, enabling joints to be obtained with a high load-carrying capacity. The quality of the joints was assessed by visual examination, macro- and micro-structural investigations, EDS analysis, the tensile lap shear test, and hardness measurements.…”

The Influence of Tool Pin Geometry and Speed on the Mechanical Properties of the Bobbin Tool Friction Stir Processed AA1050

“…After the BT penetration, the plasticized materials flow around the pin and transfer from the AS to RS during BT-FSP. The transferred materials cooled in the RS [31]. The AS generates higher shear stress (friction force) than the RS during stirring action and generates more frictional heat [32][33][34].…”