Optimization of different welding processes using statistical and numerical approaches – A reference guide

Welding input parameters play a very significant role in determining the quality of a weld joint. The joint quality can be defined in terms of properties such as weld-bead geometry, mechanical properties, and distortion. Generally, all welding processes are used with the aim of obtaining a welded joint with the desired weld-bead parameters, excellent mechanical properties with minimum distortion. Nowadays, application of design of experiment (DoE), evolutionary algorithms and computational network are widely used to develop a mathematical relationship between the welding process input parameters and the output variables of the weld joint in order to determine the welding input parameters that lead to the desired weld quality. A comprehensive literature review of the application of these methods in the area of welding has been introduced herein. This review was classified according to the output features of the weld, i.e. bead geometry and mechanical properties of the welds

Parametric Optimization of MIG Welding on 316L Austenitic Stainless Steel by Grey-based Taguchi Method

AbstractIn the present work, visual inspection and X-ray radiographic test has been conducted in order to detect surface and sub-surface defects of weld specimens made of AISI 316L austenitic stainless steels. Effect of current, gas flow rate and nozzle to plate distance on quality of weld in metal inter gas arc welding of AISI 316L austenitic stainless steel has been studied in the present work through experiments and analyses. Butt welded joints have been made by using several levels of current, gas flow rate and nozzle to plate distance. The quality of the weld has been evaluated in terms of yield strength, ultimate tensile strength and percentage of elongation of the welded specimens. The observed data have been interpreted, discussed and analyzed by using Grey - Taguchi methodology

Molecular phylogenetic inference of White-Spotted Guitarfish (Rhynchobatus australiae) collected from local Malaysian fish markets

The white-spotted guitarfish (Rhynchobatus australiae) is in high demand at local Malaysian fish markets because its fins are a valuable food source. To date, few molecular studies have characterized their genetic identity. We have conducted a molecular study to infer the phylogenetic relationships of white-spotted guitarfish, which portray a similar morphology to sharks and rays. The main objective of this study was to determine the phylogenetic position of R. australiae using cytochrome oxidase I (COI) sequences of mitochondrial DNA based on fish samples collected from local Malaysian fish markets. This study included nine genetic samples of R. australiae and fourteen samples from other members of the shark and ray families, including Sphyrna lewini (Sphyrnidae), Rhizoprionodon oligolinx and Carcharhinus sorrah (Carcharhinidae), Dasyatis zugei, Himantura walga, Himantura gerradi, Himantura jenkinsii and Neotrygon kuhlii (Dasyatidae). Chimaera fulva, a member of the Chimaera family, was used as the outgroup. Sequences in size of ~701 base pairs were successfully obtained from all fish samples. The phylogenetic tree topology was reconstructed using distance-based (neighbor-joining) and character-based (maximum parsimony) methods using MEGA and PAUP software. Results indicated that R. australiae formed monophyletic clade and is closely related to sharks (Sphyrnidae and Carcharhinidae). This conclusion was also supported by genetic distance analysis which indicated that Rhynchobatidae and sharks (Carcharhinidae and Sphyrnidae) were closer to each other than to rays (Dasyatidae). This study has proven the efficiency of the COI mitochondrial locus in revealing the phylogenetic position of R. australiae. Research findings from this study have increased our understanding of the phylogenetic relationships among guitarfish, sharks, and rays, and their respective taxonomic positions are given their shared morphological characters. This will benefit us in identifying these fish species before consumption from local fish markets

Optimization of Metal Inert Gas Pulse Brazing Process on Galvanized Steel Sheets Based on Taguchi Method

AbstractThe purpose of this research was to identify the optimal conditions of the galvanized steel sheets based on the Metal inert gas pulse brazing process (MIGPBP). The study used the Taguchi method to experimentally design the L25 orthogonal array, including five main parameters: 1) wire feed speed, 2) arc voltage, 3) travel speed, 4) peak current, and  5) pulse frequency. Each of these parameters consisted of 5 levels, and thus the experiment runs 25 times with 3 replications (75 experiments in total) to find the characteristics of the MIGPBP that were considered important parameters and were exhibited significantly, including: 1) zinc coated balance of joint (ZB), 2) area for penetration of filler metal into the fit-up (ARP), and 3) tensile shear strength (TSS). The results demonstrated that the optimum conditions of the MIGPBP of galvanized steel sheets for the ARP and TSS were 4 meter/minute wire feed speed, 18 V arc voltages; 0.6 meter/minute travel speed, 450 ampere peak current and  35 Hz pulse frequency. For the ZB, the finding indicated the wire feed speed at 3.25 m/min, the arc voltages at 18 V, the travel speed at 0.9 m/min, the peak current at 425 A, and the pulse frequency at 35 Hz to be such optimal conditions which effected the quality of zinc coated balance of joint

An Investigation of Dissimilar Welding Joint of AISI 304L Stainless Steel with Pure Copper by Nd:YAG Pulse Laser: Optimization of Tensile Strength

Nd:YAG laser welding process has successfully used for joining a dissimilar metal AISI 304L stainless steel and pure copper plates. In this study, a statistical design of experiment (DOE) was used to optimize selected LBW parameters (laser power, welding speed and pulse duration). Taguchi approach was used to design the experimental layout, each factors having four levels. Joint strength was determined using the universal testing machine (UTM). The results were analysed using analyses of variance (ANOVA) and the signal-to-noise (S/N) ratio for the optimal parameters, and then compared with the base material. And the Response can be predicted by fuzzy logic experimental results point to that the laser-welded joints are improved successfully by optimizing the input parameters using the Taguchi fuzzy approach. Also find out the effect of the focusing position on the response

An integrated approach of GRA coupled with principal component analysis for multi-optimization of shielded metal arc welding (SMAW) process

Welding distortion is a critical issue as it leads to severe deterioration of structural integrity of welded work piece and dimensional precision. This study aims at studying the e ects of shielded metal arc welding (SMAW) parameters on the evolution of mechanical properties, including tensile strength, impact toughness, and hardness, along with angular distortion on a welded joint from SA 516 grade 70. Such parameters are analyzed and optimized by employing the Taguchi method and Grey relational analysis. SA 516 grade 70 is commercially used for fabrication of storage tanks, boilers and pressure vessels. SMAW is investigated with three levels of root gap, groove angle, electrode diameter, and pre-heat temperature, which were varied on a butt joint in flat (1 G) position to determine their e ects on response variables at room temperature. Nine experiments were designed using a Taguchi L9 orthogonal array, welded according to American Society of Mechanical Engineers (ASME) section IX, and samples were prepared and tested as per ASTM A 370. The Taguchi method and Grey relational analysis were employed to observe the most significant parameters and optimal levels that synergically yield improved responses. Results are validated by conducting confirmatory experiments that show good agreement with optimum results

Two factor authentication by using SMS for web based application

Two factor authentications had two entry levels for authentication’s mechanism. This study had used Short Messaging Service (SMS) technology as a second factor in doing authentication on the web application. It can minimize the problems that occur regarding to the illegal access over the user privacy information on the Internet. The system that uses two factor authentications is capable to give the priority and safety in aspect of user’s privacy information from the web based applications

Optimization of plasma transferred arc welding process parameter for hardfacing of stellite 6B on duplex stainless steel using taguchi method

International journal of engineering and industrial management . - ISSN 1647-578X. - N. 5 (2013). - p. 39-49.Hardfacing involves the application of a deposition on the surface of a metallic workpiece by employing a welding method such as plasma transferrd arc (PTA) and has found widespread application in the steel, power, mining and in the petroleum industry. The process of hardfacing should be aimed at achieving a strong bond between the deposit and the base metal with a high deposition rate. Therefore, it is very important for the proper selection of PTA process parameters to improve weld qualities in hardfacing. The properties of the hardface materials such as mechanical strength, hardness are influenced not only by the chemical composition but also by the process parameters. The acceptable properties depends on heat input and the heat input, in turn, depends on welding current, arc voltage, etc. Therefore, weld hardfacing can be considered as a multi input, multi-output process , Stellite 6 has an outstanding resistance to seizing or galling as well as cavitation erosion and is extensively used to combat galling in valve trims, pump sleeves and liners. Hardfacing is a surface modification technology in which a specially designed alloy is surface welded in order to enhance surface properties depending on the characteristics of selected alloys. In this process, metallurgical bond forms between the coating and the substrate in this concern PTA welding process parameter are optimized for maximum hardness and defect free process, using Taguchi method for the hardfacing of Stellite on duplex stainless steel

Influence of welding parameters on grain size, HAZ and degree of dilution of 6063-T5 alloy: optimization through the Taguchi method of the GMAW process

The aim of this work is to design experiments using Taguchi’s method that determine the influence of welding parameters on the grain size, heat-affected zone and degree of dilution of the 6063-T5 alloy. The welding process used is GMAW, and the welding parameters are the power, welding speed and bevel spacing. The study of the influence of these welding parameters on the measurements made during welding (which are the size of the 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 that most influences the minimisation of these three measurements will be determined.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature