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.

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Fuzzy logic is an optimization technique used to predict the behaviour of any problem. Polyethylene (PE) sheet of thickness 3 mm was joined by means of hot press method with aluminium (Al) of thickness 1mm using lap join type. The inside surface of aluminium in the lap joint region was anodized to increase the size of surface pores and mechanical interlock between the melted polymers in the pores of anodized surface of aluminium. The anodizing process was performed by a solution of 15%wt. sulphuric acid with deionized water. The anodizing current density and time were 200A/m2 and 60 min. respectively. The hot press process parameters were; temperature: 115, 125, 135 and 145 °C, pressure: 2, 4, 6, and 8 bar and the pressing time: 1, 2, 3 and 4 min. The hot press method was successfully joined the anodized Al with PE sheet. Shear tensile test was used to estimate the shear strength of lap join. These data are optimized using a fuzzy logic concept which gives a good indication about the effect of input process parameters on the shear of joints. Increasing the applied pressure, decreasing the pressing time and increasing the temperature up to 80 °C resulted in increasing the maximum shear force of joint.

In this research, a multi-response optimization based on Taguchi method is proposed for friction stir welding (FSW) process for (2024-T3) aluminum alloy. Three different shoulder diameters of tools with tapered pin geometry of (12, 14 and 14 mm) with variable rotation speed (710, 1000 and 1400 rpm) and welding speed of (40, 56 and 80 mm/min), three different tilting angles of (1, 2 and 3 degree) and three welding direction of (1, 2 and 3 passes). The results of this work showed the single optimization by using (Taguchi method) at the optimum condition for the tensile strength and yield strength were (365 MPa) and (258 MPa) respectively; at the parameters: shoulder diameter (14 mm), rotation speed (1400 rpm), linear speed (40 mm/min), tilting angle ((3°) for tensile strength and (1°) for yield strength) and welding direction (3 passes). The results of multi-response optimization for (FSW) process at the optimum condition for tensile strength and yield strength were (371 MPa) and (268 MPa), respectively; at the parameters: shoulder diameter (14 mm), rotation speed (1400 rpm), linear speed (40 mm/min), tilting angle (3°) and welding direction (3 passes).

Purpose The purpose of this paper is to join sheets of an aluminium alloy together with pre-holed carbon steel via friction spot technique. Design/methodology/approach An AISI 1006 steel sheet was a pre-holed with a 4.8 mm diameter and put under AA5052 sheet with a lap joint configuration. The joining process was carried out by extruding the aluminium through the steel hole using a rotating tool of 10 mm diameter. Furthermore, three process parameters (pre-heating time, rotating speed and plunging depth of the tool) with three values for each parameter were used to study their effects on the joints quality. In order to join samples, nine experiments were designed according to a Taguchi method. Shear strength, microstructure and X-ray diffraction tests of the joint were carried out. Findings The joining mechanism occurred by a mechanical interlock of the extruded aluminium with the inner surface of the steel hole. The tool plunging depth had a significant effect on the shear strength of the joint. The shear strength of two joints exceeded the shear strength of the wrought material (AA5052). All samples failed with two modes: pull-out and shearing of the extruded aluminium. Originality/value For the first time, the extrusion technique was used to join AA5052 sheet together with pre-holed carbon steel, with a perfect joint efficiency.