Spot lap joining of AA5052 to AISI 1006 by aluminium extrusion via friction forming technique

Abstract

Purpose The purpose of this paper is to join AA5052 to AISI 1006 steel sheets using the spot friction forming technique. Design/methodology/approach A steel sheet was pre-holed with a diameter of 4.8 mm and pre-threaded with a single internal M6 thread. Lap joint configuration was used so that the aluminium specimen was put over steel. A rotating tool with a 10 mm diameter was used for the joining process. A Taguchi method was used to design three process parameters (plunging tool depth, rotating speed and preheating time), with three levels for each parameter. The effect of the process parameters on the joint shear strength was analysed. The macrostructure, microstructure and scanning electron microscope of the joint were investigated. The temperature distribution during the joining process was recorded. Findings The formed aluminium was extruded through the steel hole and penetrated through the thread slot. A mechanical interlock was achieved between the extruded aluminium and the steel. The plunging depth of the tool exhibited a significant effect on the joint shear strength. The joint efficiency increased gradually as the plunging depth increased. Two modes of failure were found shear and pull-out. The maximum temperature during the process reached 50 per cent of aluminium’s melting point. Originality/value For the first time, AA5052 was joined with AISI 1006 steel using a friction spot forming technique with an excellent joint efficiency.

Effect of shoulder features during friction spot extrusion welding of 2024-T3 to 6061-T6 aluminium alloys

“…The Al is extruded in the specially fabricated grove of steel workpiece and that in turn lead to joining of Al and steel. Hussein et al [20] named friction spot forming technique to produce Al-steel welding using extrusion of Al in the grove of steel when Al is kept on steel, wherein maximum joint efficiency of 125% is claimed. Jarrell et al [21] applied friction stir extrusion on thin sheets to obtain large length welds of Al-steel, without surface penetration caused by tool on Al side.…”

Joining of aluminium alloy to pre-holed carbon steel by aluminium extrusion using friction spot method

“…The shear strength of Samples 2, 3, 4, 8 and 9 converged to the shear strength of the wrought material (AA5052). For each value of the rotating speeds, minimum and maximum shear strength values of the joint were observed at the minimum and maximum plunging depth of the tool, respectively (Hussein et al , 2019). The increase in the plunging depth of the rotating tool increased the penetration of the softened aluminium through the steel hole, which increased the penetration of aluminium through the steel surface.…”

“…However, the increase in the amount of the softened aluminium increased the penetration of aluminium through the lower hole of steel, which prevented sliding of the extruded aluminium from the steel hole during the tensile test. As a result, the increase in the plunging depth increased the shear strength of the lap joint (Hussein et al , 2019).…”

Friction Spot Lap Joining of Aluminum Alloy AA6061 to Pre-Holed and Threaded Carbon Steel AISI 1006

“…This shows that the applied pressure and generated heat during the friction process were sufficient to extrude the aluminum with a uniform filling through the steel hole. Most of the joined samples exhibited the trace of the flat backup plate on the extruded aluminum metal due to high applied pressure and temperature [23]. Samples 1, 6, 11 and 16 exhibited a noticeable gap between the extruded aluminum and the inner surface of the steel hole compared with the other joined samples.…”

“…Previous studies showed that the formation of IMCs, keyholes at the interface line of welded materials reduced the joint's strength. To prevent the formation of IMCs in welding of dissimilar materials, the friction spot joining (FSJ) technique was used to join materials without the formation of IMCs [23].…”