Comparative Study and Optimization of Process Parameters of Dissimilar metal Weld Joints by GTAW Process

ABSTRACT Industries are focusing on various cost reduction initiatives by choosing alternative material without compromising quality. The main aim of this paper is to identify such an alternate material for Duplex Stainless Steel/Duplex Stainless Steel (DSS/DSS) similar metal weld joint. Similar and various dissimilar metal weld joints like DSS/DSS, DSS/Corten-A, DSS/Cold Rolled Steel and DSS/Hot Rolled Steel were assessed in this paper and the results have been compared to find out the superior dissimilar metal in terms of Tensile strength. Objective of this work is to optimize the process parameters for the best superior dissimilar metal weld joint by using Taguchi method. Voltage, Current and filler feed rate were chosen as a control factors considering the impact on the input variables. Ultimate tensile strength has been taken as response variable to calculate the signal-to-noise ratio. Analysis of variance (Anova) was used in order to identify the percentage contribution for all the factors as well as high significant factor which is contributing for the optimum resul

PREDICTING THE STIFFNESS OF BIAXIAL BRAIDED FIBER COMPOSITES BY INCORPORATION OF CARBON NANO FIBER

In this study, carbon nano fibers (CNFs) were mixed into epoxy resin through a magnetic stirrer and again mixed using ultra sonicator. Using hand layup technique, biaxial braided fiber composites were prepared with unfilled, 0.2, 0.5 and 1 wt% CNF. Tensile test and shear test was performed to identify the tensile strength and shear strength of the composites. Fractured surface of the tensile specimens were examined by scanning electron microscopy to identify morphologies of nanoparticles. A discrete three layer model was developed for prediction of the tensile modulus and shear modulus of biaxial braided fiber composites. Theoretical and experimental values were compared. The experimental and theoretical results show that the addition of CNF in the epoxy matrix had significant influences on the mechanical properties of biaxial carbon braided fiber composites. CNF inclusion with braided composite promoted the tensile modulus, tensile strength, shear modulus and shear strength up to 0.5wt% of the biaxial carbon braided fiber composites

Research on Gas Tungsten Arc Welding of Stainless Steel – An Overview

Abstract — Gas Tungsten Arc welding (GTAW) or Tungsten Inert Gas (TIG) is an electric arc welding process, which produces an arc between a nonconsumable tungsten electrode and the work to be welded. TIG is used very commonly in areas, such as rail car manufacturing, automotive and chemical industries. Stainless steel is extensively used in industries as an important material, because of its excellent corrosion resistance. TIG welding is one of the welding processes, often used to weld similar and dissimilar stainless steel joints. In this paper, an attempt is made to review and consolidate the important research works done on GTAW of stainless steel in the past, by various researchers. It has been observed, that most of the works done, is on austenitic stainless steel, which is the most widely used type of stainless steel in the world. Major areas of research have been in characterization of weld, dissimilar metal welding, parameter optimization, process modeling, failure analysis and automation of TIG welding process. This paper is aimed at, to give a brief idea about the research works done in the past, on TIG welding of stainless steel by various researchers, by highlighting the important conclusions and results arrived at and thereby providing the right direction for fresh researchers for future research in this particular area

Multi-objective Optimization of Resistance Spot Welding of AISI 409M Ferritic Stainless Steel

271-275Resistance spot welding is a widely used sheet metal joining process in automobile and rail car manufacturing industries. One of the most important quality characteristics of a spot welded joint is its tensile shear strength, as it is crucial in improving the crashworthiness of the vehicle. Amount of indentation made by the electrode on the surface of the sheet during spot welding, is another quality characteristic that needs to be minimized, to improve the surface finish and aesthetic value. Ensuring maximum strength of the spot weld joint, while keeping indentation at the minimum level is one of the major challenges in spot welding. In this work, multi-objective Taguchi method has been applied for optimization of various input parameters in resistance spot welding of AISI 409M ferritic stainless steel sheets, to maximize the tensile shear strength of the weld joint and minimize the surface indentation simultaneously. Furthermore, a linear response surface model has been developed to correlate tensile shear strength and indentation values with process parameters. The optimum values of control parameters were 11.5 KA for current, 14 cycles for weld time and 3.5 KN for electrode force. Current was found to be the most influential parameter affecting tensile shear strength and indentation. Results of the optimization process were validated by confirmation test

Effect of process parameters on the mechanical performance of resistance spot welded joints of AISI 409M ferritic stainless steel

11-18In this study, the effect of process parameters on mechanical performance of the resistance spot welded joints of AISI 409M ferritic stainless steel sheets is investigated. Mechanical performance of the spot weld is evaluated in terms of output quality characteristics, such as load carrying capacity and energy absorption capacity. Important process variables, such as current, time, electrode force and holding time were varied separately and corresponding output parameters, which decide the mechanical performance of the spot welded joint have been analysed. Weld nugget geometrical parameters such as nugget size and surface indentation have also been analysed with respect to various process variables. It has been found that peak load and energy absorption capacity are in direct relationship with welding current as well as welding time, in expulsion free welds. Surface indentation increases with increase in current and welding time. It has also been observed that increasing electrode force results in slight reduction of both tensile shear strength and energy absorption capacity. The effect of holding time on mechanical performance of the resistance spot welded joint is found to be almost insignificant. Regression-based relations are developed to correlate the mechanical performance of the spot welds with nugget size