Influence of Welding Parameters On Grain Size, Haz and Degree of Dilution in 6063-t5 Alloy. Optimisation Through the Taguchi Method of the Gmaw Welding Process.

The aim of this work is to carry out the design of experiments that determine the influence of the welding parameters using Taguchi’s method on the grain size, HAZ, and the degree of dilution in 6063-T5 alloy. The welding process used is GMAW and the welding parameters are power, welding speed and bevel spacing. The study of the influence of the welding parameters on the measurements made in the welding (which are the size of heat affected zone, the degree of dilution, and the grain size) allows one to determine the quality of the joint . In addition, the welding parameter most influential in minimising the three measurements will be determined.

Establishing optimal friction stir welding parameters for AA2219-T87 Al-alloy using comprehensive RSM and GA approach

AA2219-T87 aluminium alloy has been used in aerospace applications because of its high strength, low density and resistance to corrosion. The copper in the alloy improves the hardness and lowers melting point, which makes two sections easily joined with a process called friction stir welding of aluminium alloy. In the present work, heat-treated AA2219 alloy was butt welded by solid-state friction stir welding process. This work aims to develop a suitable combination of welding parameters for producing defect-free weld joints of AA2219 alloy to improve tensile and corrosion properties. The most influencing control parameter for optimising the friction stir welding responses was determined using sophisticated design of experiments (DOE) techniques. Ultimate tensile strength and corrosion resistance are observed as responses in this study. To achieve the desired weld responses, a three-factor, three-level Box-behneken design was used. Analysis of Variance (ANOVA) was carried out to examine the interaction effect and significant welding parameter to set the optimal level of welding conditions. Multi-response regression equations have been developed using response surface methodology (RSM) to estimate the output characteristics of weld. The Genetic algorithm (GA) was used to optimise the predicted mathematical model under given optimization constraints. The results shown that the optimum responses are obtained at input factors rotational speed 300 rpm, welding speed 80 mm/min, and axial force of 10kN.

Study of the Diffusible Hydrogen Content Affected from the Welding Electrode Humidity

The influences of moisture corruption and drying considerations on diffusible hydrogen were examined in this study. Two trials were carried out on an arc welding procedure, with the first being an assessment of the results of moisture contamination and the second being a test of the impact of welding constraints on diffusible hydrogen content. For example, the dispersible hydrogen found in welds was likened to the hydrogen levels of different unused electrodes. To calculate the proper drying constraints (Time and Temperature) for an applicable moisture contamination level in the weld electrode, an empirical equation was devised. For electrodes with a small diameter and welding parameter limits typically used for out-of-position welding, the equation is appropriate.

Microstructure and Mechanical Performances Analyses on Probeless Friction Stir Spot Welds of AA6061-T6 Aluminum Sheets

Probeless friction stir spot welding (PFSSW) is a variation of conventional friction stir spot welding (CFSSW), which solves the keyhole defect in CFSSW welds. In this work, four types of probeless tools were designed based on helix and spiral feature: small curvature helix (involute tool, IT), large curvature helix (archimedes tool, AT), spiral line (scroll tool, ST) and no feature (flat tool, FT). AA6061-T6 sheets with a thickness of 1.5 mm were welded using the designed probeless welding tools. The effect of tool shapes on the microstructure and mechanical properties of friction stir spot welded AA 6061-T6 aluminum alloy sheets was investigated using different rotational speeds, plunging depths and dwell times. The Taguchi method was utilized to obtain the optimal welding parameter combination for the four tools. And, the tensile-shear mechanical properties of FSSW specimens were characterized under the optimal parameters. The results show that a basin-shaped profile appeared in the weld metallography using the groove tools. The tensile shear failure load (TSFL) of IT (~6.97 kN) was higher than that of ST (~6.49 kN), AT (~6.19 kN) and FT (~5.67 kN), sequentially. Three different fracture modes, interfacial fracture, plug fracture and mixed-mode fracture were observed in the tensile-shear tests of weld specimens.

Optimization of TIG Process Parameter in Improving Mechanical Properties of S304 Stainless Steel Using a Grey Based Taguchi Method

Tungsten inert gas welding is popular known welding technique for ferrous & nonferrous. Stainless steel grade 3HQ (S30430) is a specialized wire grade with very wide usage for manufacturer of stainless steel fastener. It has now totally replaced Grade 384 and 305 for heading application. The stable austenitic structure makes 302HQ nonmagnetic, even after substantial cold work, and also results in excellent toughness, even down to cryogenic temperatures. This paper attempts in optimizing the Tungsten Inert Gas (TIG) welding process parameter. The effect of various parameters and their influence is important to determine the strength of welded joint. To obtain a good quality weld, it is therefore, essential to control the input welding parameters. Therefore appropriate selection of input welding parameter is necessary in order to obtain a good quality weld and subsequently increase the productivity of manufacturing industry. This paper present multi objective optimization using grey relation analysis (GRA) for S30430 with TIG process to determine the suitable selection of parameters Experiment were conducted according to Taguchi's design of experiments (DOE) with orthogonal array L9 is used, mathematical model was developed using parameters such as speed (mm/min), current (Amp), voltage (V), depth of penetration (mm). After conducting experiment and collecting data, signal to noise ratio were determined by using Minitab18 and it is used to obtain optimum level for every input parameter.

Interfacial Bonding and Mechanical Properties of Al/Mg Dissimilar Refill Friction Stir Spot Welds Using a Grooved Tool

Al/Mg dissimilar welds were successfully fabricated by refill friction stir spot welding using a grooved sleeve tool. Influences of sleeve penetration depth and rotational speed on the weld formation and mechanical performance were systematically evaluated in terms of welding parameter optimization, interfacial bonding mechanism, hardness distribution and welded joint strength. The results indicated that the success of joining Al alloy to Mg alloy significantly depends on tool sleeve penetration depth. The interfacial bonding mechanism compromised both metallurgical bonding and mechanical inter-locking. Intermetallic compound layers of Al3Mg2 and Al12Mg17 were formed at the Al/Mg interface. The thickness of the intermetallic compound (IMC) layer at the weld center increased from 20–30 μm to 40 μm when the rotational speed increased from 1000 to 2000 rpm. The minimum hardness was 80 HV in Al 7075 and 52 HV in ZEK 100; both were measured in the heat affected zone. The welded joint lap shear strength decreased, and the scatter increased with the increasing of rotation speed, whose maximum was 3.6 kN when the rotational speed was 1000 rpm. In addition, the failure mechanism was determined by tool rotational speed, and found to be interfacial failure under a rotational speed of 1000 rpm and nugget pullout under a rotational speed of 2000 rpm.

Investigation of Factors Affecting Friction Stir Welding of Polyethylene by ANOVA Analysis

The variables that are effective in joining high density polyethylene sheets by friction stir welding (FSW) have been investigated. In order to understand the effects of welding parameters, using Taguchi optimization, tool rotation speed, feed rate, shoulder diameter and pin diameter values were selected in a wide range. The results obtained with Taguchi optimization method were evaluated according to the highest / the best signal-noise ratio. Macro photographs taken cross-sectional view taken the weld seam, SEM images and hardness measurements were used to evaluate. As a result of the evaluation, the accuracy of the optimization was found to be approximately 96 %. As a result, feed rate and shoulder diameter were determined as the most effective parameter affecting the welding quality and welding performance. These two parameters (shoulder diameter and feed rate) have found to effect of approximately 65 % on tensile strength, weld quality and hardness. Finally, it has obtained that the most effective welding parameter was the shoulder diameter with 40.81 %.