Microstructure and Mechanical Properties of Al/Steel Friction Stir Lap Weld

Abstract

Abstract:The friction stir welding tool with convex pin tip was designed to realize the lap joining of 6082-T6 aluminum alloy and Q235A steel. With decreasing welding speed and increasing rotation speed, the basic constitutions of mixed stir zone changed from α-Fe fine grains, thin intermetallic compound (IMC) and Al/Fe composite structure to hook-like and chaotic mixed layered structure, resulting in joint deterioration. The maximum shear load can reach 7500 N and is predominately affected by the morphology of the IMC layers, which in turn depend on rotation speed, welding speed and other parameters. Nano-hardness decreases from about 3.9 GPa in the upper steel surface layer to about 1.3 GPa in the steel base material. Microhardness profile reveals that the maximum hardness occurs at the interface zone. The morphology of layered structure, FeAl 3 IMC thickness and steel grain size can be controlled by choosing suitable welding parameters and tool shape.

Mechanical Properties and Microstructure of Dissimilar Friction Stir Welding of Pure Aluminum to Low Carbon Steel

“…To overcome these welding problems, it should weld this joint without melting. There are solid state welding processes which join similar or dissimilar metals without melting such as friction welding [9], ultrasonic joining [10], FSW [11][12][13][14][15][16][17][18][19][20][21][22]. FSW was invented and patented by The Welding Institute (TWI) in1991 [23].…”

“…The tool of the FSW consists of a shoulder which helps to force the plasticized metal and a pin to stir this metal from side to side to make a joint. Few studies were investigated the welding of aluminum to steel by FSW [11][12][13][14][15][16][17][18][19][20][21][22]. M. Dehghani et al [11] welded mild steel to AA3003-H18.…”

“…Shuhuai et al [19] obtained the best strength at the formation of thin IMC at the interface (less than 1 μm). Masoumen et al [20], Long et al [21] and Z. shen [22] used a lap configuration to join aluminum to steel. These studies circled the effect of the formation of IMC and studied the effect of this on the quality of the joint.…”

Recent Achievements in Rotary, Linear and Friction Stir Welding of Metals Alloys

“…In more detail, the contributions have concerned the following topics.The effect of cold rolling performed after friction stir welding (FSW) on the mechanical properties and formability of joints in AA5754-H114 aluminum alloy [1].The microstructure evolution of the welded joints of AA6082-T6 obtained using the bobbin friction stir welding process with a focus on grain refinement [2].The characteristic features of the entry and exit defects in the weld structure and formation mechanism of them during the BFSW process. The issue was investigated using stacked layers of multi-colored plasticine for the material flow detection [3].The thermo-structural analysis of material behavior, material flow, and defect generation during the friction stir butt-welding of 5083-O sheets [4].The characterization of the dissimilar friction stir weld of Ti-6242 S and Ti-54M in terms of microstructure, microhardness, fracture morphology, and material migrating from the retreating (RET) side to the advancing (ADV) one [5].The characterization of the interface of friction stir lap welding joints of 6082-T6 aluminum alloy and Q235A steel [6].The investigation of the microstructure evolution and properties response of a friction-stir-welded copper-chromium-zirconium alloy [7].The study of the influence of the process parameters on the vertical force generated during friction stir welding of AA6082-T6 aluminum alloy sheet blanks [8].The role of mechanical connection in friction stir keyholeless spot welding of AZ31B Mg alloy, Mg99.50, DP600, and non-zinc-coated DP600 lap welding [9].The application of a fully coupled thermo-mechanical model together with an enhanced friction law for the simulation of an FSW process with a cylindrical threaded pin tool [10].The identification of the chemical composition of etchant reagents for metallographic examination of the friction-stir welded A6082-T6 alloy [11].The study of an advanced meshfree computational framework to be used for the determination of optimal process parameters for the friction stir welding of an AA6061-T6 butt joint [12].The numerical modeling approach to the study of the linear friction welding of 30CrNiMo8 high strength steel Hero chain [13].…”

“…The characterization of the interface of friction stir lap welding joints of 6082-T6 aluminum alloy and Q235A steel [6].…”