Manufacturing Technology Today

K. S. Pujari ¹, D. V. Patil ², Akash Maney ¹, A. Abhishek ¹, K. Kartik ¹, H. Chetan ¹

Affiliations
1 Welding Research Center, KLS VDRIT, Haliyal, IN
2 Department of Mechanical Engineering, Research Center, SDMCET, Dharwad, IN

Abstract

The most attractive properties of aluminum and its alloys which make them suitable for a wide variety of applications are their light weight, appearance, frabricability, strength, and corrosion resistance. Among aluminium alloys AA7075 alloy has many attractive properties compared to other alloy it is economical and versatile to use this is the reason it is very widely used in the aerospace, automobile and other industries. AA7075 aluminum alloys are important structural materials due to their high strength and increased strength to weight ratio. The effects of Sc addition on the microstructure and mechanical properties of the AA7075 wrought zinc alloy were investigated by using optical microscope, scanning electron microscopy, and tensile testing. The experimental results show that a minor Sc addition to AA7075 alloy has an obvious effect on the refinement of the microstructure of the AA7075 alloy. During casting, incomplete dynamic recrystallization occurs in all the alloys, and the recrystallized grains become much finer with increasing Sc addition. The ultimate tensile strengths of AA7075 evidently increase with the addition of Sc, but the elongations decrease. The AA7075 alloy with 0.23% (weight fraction) Sc addition is found to have the tensile strength of about 468.8 MPa and the yield strength of about 324.3 MPa. Further by T6 tempering heat treatment, the tensile strength of the alloy containing 0.23% Sc is increased to 485.8 MPa and yield strength 335.49 Mpa.

Keywords

AA 7075 Alloy, Grain Refinement, Tensile Properties, Heat Treatment, Scandium.

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K. S. Pujari ¹, D. V. Patil ², Gurunath Mewundi ¹, Prajakta S. Patil ¹

Affiliations
1 Welding Research Center, KLS VDIT, Haliyal, IN
2 Department of Mechanical Engineering, SDMCET Research Center, Dharwad, IN

Abstract

The mathematical model is developed to predict pulsed gas tungsten arc welded (GTAW) joints of AA 7075-T6 aluminium alloy. The mathematical model is developed by incorporating the process parameters like peak current, base current, welding speed, and pulse on time. All the experiments were conducted on the basis of four factors, four levels Composite Design Matrix. In this study an attempt is made to develop mathematical model by preplacing the filler wire in to the weld groove. The optimized GTAW process parameters illustrate that improvement in the tensile properties of welded joints. A mathematical model were developed at 95% confidence level and tested for adequacy. The developed model can be used in industry for predicting tensile strength of AA 7075-T6 aluminium alloy joints. The results shows that welding speed greatest influence on tensile strength subsequently with peak current, pulse on time, and base current when filler wire placed in to the weld groove before starting the welding.

Keywords

Gas Tungsten Arc Welding Method (GTAW) AA7075-T6 Aluminium Alloy, Response Surface Methodology, Central Composite Design Matrix, Ultimate Tensile Strength, Optimization.

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