Investigations of tool tilt angle on properties friction stir welding of A441 AISI to AA1100 aluminium

Abstract

The aim of this article is the investigation of the effects of tool tilt angle on the friction stir welding of aluminium to the steel butt joint. For this purpose, 1°, 2° and 3° tilt angles are selected to friction stir welding of AA1100 to A441 AISI, while the other process parameters (i.e. tool rotational speed, travelling speed, tool offset and plunge depth) kept constant. The results showed that with increasing tool tilt angle, the interaction between two metals and axial force increased. The increasing tool tilt angle caused more surfaces to mingle, internal mixing and frictional heat generation. The results of the microstructure of joints revealed that the AA1100 microstructure is more thermo-mechanically affected than A441 AISI. The AA1100 average grain sizes at stir zone were 1.2, 1.6 and 2 µm and at A441 AISI were 6, 7 and 9 µm at 1°, 2° and 3° tilt angles, respectively. The maximum tensile strength of joints was 75% of the aluminium base metal, which was produced at 2° tilt angle. The higher heat generation and axial force at upper tilt angle cause separation of the steel fragments on the aluminium matrix and formation of Al-Fe intermetallic compound. These phenomena lead to increase in the micro-hardness of the joint at the upper tool tilt angle.

Main Issues in Quality of Friction Stir Welding Joints of Aluminum Alloy and Steel Sheets

“…Particularly, tool tilt angle increases vertical force and, as a result, weld temperature. Elyasi et al [52] reported an increase in temperature as tool tilt angle increased from 1° to 3° during FSW of AA1100 aluminum alloy and A441 AISI steel, as illustrated in Figure 14. The nature of IMCs depended on tilt angle and ensuing temperature: FeAl3 formed at 1° and 2° tilt angle, whereas FeAl2 at 3°.…”

“…Weld temperature for different tool tilt angles during FSW of AA1100 aluminum alloy and A441 AISI steel (Reproduced from[52], with permission from SAGE UK, 2019).…”

“…Weld temperature for different tool tilt angles during FSW of AA1100 aluminum alloy and A441 AISI steel (Reproduced from[52], with permission from SAGE UK, 2019).The nature of IMCs depended on tilt angle and ensuing temperature:FeAl 3 formed at 1 • and 2 • tilt angle, whereas FeAl 2 at 3 • . The thickness of IMCs increased from 1.5 µm to 3 µm coherently with an increase of tilt angle from 1 • to 3 • .…”

Influence of Tool Tilt Angle on Material Flow and Defect Generation in Friction Stir Welding of AA2219

“…Investigation of tilt angle on the material flow by Arash 13 , et al showed that tool tilt angle is an effective factor in controlling the material flow that also results in imperfection in welds. Effect of tool tilt angle on forces and torque generated during welding of some other aluminium alloys is recently studied but still, the effect of tool tilt angle on defects and material flow is not brought out 14,15 . long 16 , et al studied the effect of tool tilt angle on weld formation, but the correlation of weld defects with material flow strain rate is not covered, though visualisation of material flow is done based on peak temperature experienced by the weld.…”

Interfacial Microstructure and Shear Strength of Brazed Cu-Cr-Zr Alloy Cylinder and Cylindrical Hole by Au Based Solder

“…Qiao et al [8] and Shanjeevi et al [9] have reported their study on optimization of friction welding parameters for AISI 304L austenitic stainless steel and copper joints in power generators. Elyasi et al [10] have reported their study on the effect of tool tilt angle on properties and formation of intermetallic compounds in friction stir welded A441 AISI to AA1100 aluminum butt joints.…”