Manufacturing Technology Today

K. Elangovan ¹, V. E. Annamalai ¹, A. K. Lakshminarayanan ¹

Affiliations
1 Department of Mechanical Engineering, SSN College of Engineering, Kalavakkam, Chennai, IN

Abstract

Low alloy low carbon steels are extensively used for automotive applications mainly due to their good impact resistance, specific strength and formability. Electrical Resistance Spot Welding (ERSW) is currently used as a method of joining sheet metal together in automotive industries. Generally materials of similar thickness are blanked, preformed and then welded together to make parts like automobile door, bodies and number of similar parts. ERSW process is relatively faster, but it involves large amounts of current to make joints and cooling equipment to keep the electrode in normal working temperature. Friction stir spot welding (FSSW) is a relatively new type of welding process, which is a derivative of friction stir welding. In this process, a rotating tool is plunged in to the material under high force to create a bond. Joints are made by FSSW process and the macrostructure, microstructure and lap shear tensile strength of these joints are characterized. The metal flow during FSSW process is investigated on samples to gain better understanding of welding mechanisms. The results of the lap shear tensile test indicated that the combination of 900 rpm, 0.18mm plunge depth and 20s dwell time yielded a maximum lap shear tensile strength of 5.9 KN.

Keywords

Friction Stir Spot Welding, Automotive Steel, Lap Shear Tensile Test.

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A. K. Lakshminarayanan ¹, V. Balasubramanian ¹

Affiliations
1 Centre for Materials Joining & Research (CEMAJOR), Dept. of Manufacturing Engg., Annamalai University, Annamalai Nagar, IN

Abstract

The effect of rotational speed, welding speed and tool shoulder diameter on the tensile and impact properties of AISI 409M ferritic stainless steel joints made by friction stir welding are investigated. The experiments were conducted based on three-factor five-level central composite rotatable design and empirical relationships were established between the process parameters (rotational speed, welding speed and tool shoulder diameter) and quality characteristics (tensile strength and impact toughness) of friction stir welded ferritic stainless steel joints. Furthermore, the numerical multiobjective optimisation was used to optimise the friction stir welding process parameters.

Keywords

Ferritic Stainless Steel, Tensile Strength, Impact Toughness, Optimisation.

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M. Jayaraman ¹, R. Sivasubramanian ², V. Balasubramanian ³, A. K. Lakshminarayanan ³

Affiliations
1 Dept. of Mechatronics Engg., Kongu Engg. College, Perundurai, Erode, IN
2 Dept. of Mechanical Engg., Coimbatore Institute of Technology, Coimbatore, IN
3 Centre for Materials Joining Research (CEMAJOR), Dept. of Manufacturing Engg., Annamalai University, Annamalai Nagar, IN

Abstract

This paper discusses the use of Taguchi technique for maximizing the tensile strength of friction stir welded cast aluminium alloy A413. The experiments have been conducted using Taguchi's experimental design technique. The friction stir welding (FSW) process parameters namely tool rotational speed, welding speed, axial force play a major role in deciding the weld quality. The effect of process parameters on tensile strength is evaluated and the optimum welding condition for maximizing the tensile strength is determined. The analysis of variance and the signal to noise ratio of robust design are employed to investigate the influence of process parameters on the tensile strength of friction stir welded A413 aluminium alloy. To correlate the process parameters and the measured tensile strength, a mathematical model has been developed by multiple linear regression analysis. The developed mathematical model is found to be very useful for predicting the tensile strength of friction stir welded A413 aluminium alloy.

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