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Experimental Investigation for Gas Metal Arc Welding Process for Maximizing Tensile Strength of AA7075-T73

Research Paper (postgraduate) 2016 4 Pages

Materials Science

Excerpt

Abstract- In this paper, experimental investigation is carried out for Gas Metal Arc welding process for optimizing the tensile vigor of Aluminium Alloy7075-T73.This is arduous to weld Aircraft material utilizing Gas Metal Arc welding process. In this paper the L9 orthogonal array is employed to design the experiments. The experimentation was carried out in Ador Welding Ltd. Pune and the tensile vigor was quantified utilizing Macrocosmic Testing Machine (UTM) at the Sharadchandra Pawar College of Engineering, Otur, workshop.

The cull of erroneous parameters for welding may hazardous to the whole process and positions. This paper proposes and demonstrates the Taguchi’s Method for evaluating the performance measures of GMAW process. The input parameters such as current (Amp), Voltage (V0), welding speed (mm/min) and gas flow rate (Lit/min) are considered for study with tensile vigor as replication factor. The result of the paper can be utilized for maximizing the tensile vigor of AA7075-T73.

Keywords-Taguchi Method; GMAW; AA7075-T73,UTM,tensile strength.

I.INTRODUCTION

The aluminum alloys, such as 7075-T73 are employed widely in the aerospace industry. This is a highest vigor aluminum alloy. This alloy is frequently employed in high performance applications such as Aircraft fittings, gears and shafts, fuse components, meter shafts and gears, missile components,regulating valve components, aircraft, aircraft and defense applications. This alloy is considered unsuitable for arc welding.The preferred welding process for fabricating the AA7075-T73 alloy is generally the Gas Tungsten Arc Welding (GTAW) process and the Gas Metal Arc Welding (GMAW)process due to their comparatively more facile applicability and better cost-cutting measure.In study GMAW process is considered with Argon gas shielding environment [5].

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Figure 1: Principle of GMAW process [5]

The Gas metal arc welding (GMAW) is a semiautomatic welding process that utilizes a wire electrode alimented through a welding gun. This perpetual wire alimenting during welding liberates up the welder and sanctions him or her to focus planarity on the process include its high deposition rate, efficient utilization of filler metal, elimination of slag and flux abstraction, and reduction of smoke and fumes.A disadvantage is that GMAW requires more equipment, making it less portable [6].

The Weld Fusion Zone (WFZ) characteristically exhibits coarse columnar grains due to the prevailing thermal conditions during the weld metal solidification. This often results effect in inferior weld, mechanical properties and poor resistance to sultry cracking.

II.LITERATURE REVIEW

S. D. Ambekar, S. R. Wadhokar investigated the optimization of Gas metal arc welding process parameters (GMAW) of Martensitic Stainless steel work piece AISI 410 utilizing Taguchi technique. This paper presents the effect of welding parameters like welding speed, welding current and wire diameter on the perforation. The ANOVA and signal to noise ratio (S/N ratio) is applied to identify the most paramount parameter and presaged optimal parameter setting. It is observed that the welding speed is most influencing factors and gas flow rate is least influencing factor [1].

Pawan Kumar, B.K.Roy, Nishant investigated the utilization of Taguchi’s Parameter Design methodology for Parametric Study of Gas Metal Arc Welding of Stainless Steel & Low Carbon Steel. In this research work, bead on plate welds were carried out on AISI 304 & Low Carbon Steel plates utilizing gas metal arc welding (GMAW) process. The input process variables considered here include welding current, welding voltage & gas flow rate. Subsequently, utilizing analysis of variance (ANOVA) the consequential coefficients for each input parameter on tensile vigor & Hardness (PM, WZ & HAZ) were resolute and validated. In this paper, the optimization of the process parameters for GMA welding of stainless steel and low carbon steel with more preponderant weld vigor has been reported.The Nominal-the-better quality characteristic considered in the hardness presage.The experimental result shows that the hardness is greatly ameliorated by utilizing this approach [2].

Vikram Singh In this research work, experiments were carried out on AISI 1016 mild steel plates utilizing gas metal arc welding process. Taguchi method is utilized to formulate the experimental design. The exhaustive survey suggests that some control factors viz. arc voltage, welding speed, Welding Position Gap, gas pressure and root gap, wire aliment rate etc. predominantly influence the Tensile Vigor weld. An Orthogonal array, signal to noise (S/N) ratio and analysis of variance (ANOVA) employed to investigate the welding characteristics of Mild steel of AISI 1016 material & optimize the welding parameters [3].

III. TAGUCHI’S DESIGN METHODE

Taguchi Technique is employed to orchestrate the experiments. The Taguchi method has become a potent implement for amending productivity during research and development, so that high quality products can be engendered expeditiously and at low cost. Dr. Taguchi of Nippon Telephones and Telegraph Company, Japan, has developed a method predicated on "ORTHOGONAL ARRAY" experiments which gives much reduced "variance” for the experiment with "optimum settings" of control parameters. Thus the espousement of Design of Experiments with optimization of control parameters to obtain best results is achieved with the Taguchi Method. " Orthogonal Arrays" (OA) provide a set of well balanced (minimum) experiments and Dr. Taguchi's Signal-to-Noise ratios (S/N), which are log functions of desired output, accommodate as objective functions for optimization, avail in data analysis and prognostication of optimum results.

A. Signal to Noise Ratio

In this investigation, the “Larger is Better” criteria is applied to calculate the S/N ratio for response factor such as tensile strength of welded specimens.

Larger-The-Better:

n = -10 Log10 [mean of sum squares of reciprocal of measured data]

B. Work Material

The work material used for present work is Aluminium Alloy 7075-T73, the dimensions of the work piece length 150mm, width of 75mm, thickness 7mm.Argon is used as inert gas.

Table 4:L9 Orthogonal Array Design

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Table 1: Chemical Analysis (wt %) of the base metal

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Table 2: Chemical Analysis (wt %) of the filler wire used (ER-5183)

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Figure 1: Specimens after trials

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Details

Pages
4
Year
2016
ISBN (eBook)
9783668142640
File size
727 KB
Language
English
Catalog Number
v315435
Grade
Tags
Taguchi Method GMAW AA7075-T73 UTM tensile strength Gas Metal Arc Welding

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Title: Experimental Investigation for Gas Metal Arc Welding Process for Maximizing Tensile Strength of AA7075-T73