Welding Journal - April 2012 - (Page 106-s)

Design of Experiment and Goal Programming Application for the GMAW Process An integrated experimental design and goal programming combination are proposed to determine critical process variables BY Y. T. İÇ, F. ELALDI, F. PAKDIL, AND N. E. İ. PEK ABSTRACT The gas metal arc welding (GMAW) process is extensively used in manufacturing for a variety of ferrous and nonferrous metals because it greatly increases the quality of welding. The objective of this study is to develop an approach that enables the determination of critical GMAW variables and optimization of process variables by using integrated design of experiment (DoE) and goal programming (GP) methods conjunctively. This paper presents a methodology for simultaneously determining the variables of a GMA process with multiple performance objectives utilizing full-factorial design of experiments, regression analysis and goal programming. Three GMAW process variables formulated using regression analysis, are simultaneously optimized utilizing the GP method. Results were validated and showed that the proposed method provided more accurate approximations, increasing the quality of the GMA welding process. multiple performance responses through a GP formulation with the regression equations of welding variables. Application steps of this study are illustrated in Fig. 1. The basic welding variables used in this study were groove angle and joint geometry to determine the effect on mechanical properties for tension and compression loading of butt-joint-welded armor steel. Armor steel plates used in the study were prepared using V- and double-V-groove joint geometries and two different groove angles: 48 and 60 deg. Welding was performed with the GMA process. During the study, tension and compression tests of the welded joints were performed, and tensile properties and compression strength of the welded plates were examined. WELDING RESEARCH Introduction Gas metal arc welding (GMAW) is an arc welding process in which the electrode is a consumable bare metal wire, and shielding is accomplished by flooding the arc with gas (Ref. 1). When the process was first introduced, it was applied to the welding of aluminum using inert gas (argon) for arc shielding. The name given to this process at that time was MIG (metal inert gas) welding. Shielding gases for the GMAW process include inert gases such as argon and helium for aluminum welding, and active gases such as CO2 for steel welding. The development of GMAW for steel welding has led to the use of gas mixtures, such as CO2 and argon, or oxygen and argon (Ref. 1). Gas metal arc welding is affected by various variables such as welding geometry, groove angle, and shielding gas type and mixture. Although many experimental design approaches are now available to facilitate the understanding of the effects of process variables on the welding performance selection, this paper attempts to explore the applicability of integrated design of experiment (DoE) and goal proY. T. iÇ (ytansel@baskent.edu.tr) and F. PAKDIL (fpakdil@baskent.edu.tr) are with Department of Industrial Engineering, and F. ELALDI (elaldi@baskent.edu.tr) and N. E. i. PEK (nezgi@baskent.edu.tr) are with Department of Mechanical Engineering, Baskent University, Ankara, Turkey. gramming (GP) methods to determine the optimal GMAW variables in a real-time industrial application. There are previous studies that aimed to increase welding process performance. However, a search of the Science Direct (Ref. 2) electronic database from 2000 to the present determined there has been no study that particularly combines DoE and GP simultaneously in the welding process design. In this regard, the method of integrating DoE, regression analysis, and GP is applied to determine optimum welding parameters for the first time. In this study, DoE and GP methods are implemented together to identify critical factors of the GMA variables by fitting a polynomial to the experimental data in a multiple linear regression analysis. The main objective of this study is to present an integrated GMA welding design approach by 1) addressing both design and process variables simultaneously, 2) modeling performance responses of the GMAW process using DoE and regression analysis, and 3) achieving desired levels of Literature Review In a welding process, the primary task is to select a combination of process variables that produces an acceptable quality level for production. In a number of published studies, several methods have been proposed to predict and understand the effects of the process variables on welding performance. Generally, two major independent research areas are utilized to improve welding performance. These areas include the empirical method based on studies of real welding situations, and mathematical model- or experimental design-based studies. As an example of the empirical method-based studies, Alam et al. (Ref. 3) presented a study on understanding the interacting geometrical causes for the value and location of the peak stress in manifold laser weld geometries. Using finite element analysis (FEA), they endeavored to provide applicability of the findings to a much wider range of joint and root designs. In another study, Kim et al. (Ref. 4) proposed a method for determining the near-optimal settings of welding process parameters using a controlled random search (CRS) in which the near-optimal settings of the welding process parameters were determined through experiments. KEYWORDS Gas Metal Arc Welding Armor Steel Design of Experiment Goal Programming Process Variables 106-s APRIL 2012, VOL. 91

Table of Contents for the Digital Edition of Welding Journal - April 2012

April 2012 - TOC Listing
Unlocking Your Gas Metal Arc Welding Potential - A study sponsored by the National Shipbuilding Research Program investigated low-cost modifications to equipment or parameters that improved welding performance - P. A. Blomquist
Community College Welding Program Update - Many community colleges around the country are equipping future workers with the skills manufacturers need D. Postlethwaite
Modern Power Source Technology Drives Process Improvement - New technology in weld monitoring is making it easier to access the data by all the appropriate personnel and understand how it should be applied to benefit weld quality - T. McEllis
Building a Welding Career from the Ground Up - A thirty-two-year career welder shares her passion for the profession with others in hopes of inspiring them to expand their skills and knowledge
How Today’s Power Sources Aid Pulsed GMAW - The advanced welding machines of today can deliver power to the arc in almost any form and can react with split-second timing to avoid adverse arc phenomena - L. Barley
Fiber Lasers Perform Precision Cutting for Medical Devices - There are many methods to cut thin tubular structures often used in medical devices, but fiber lasers are emerging as the precision machines of choice
Arc Characteristics in Pulsed-GMA Welding with Acute - Groove Angles The characteristics of a joint tracking sensor were monitored under conditions of different groove angles and root openings - R-H. Kim et al.
Design of Experiment and Goal Programming Application for the GMAW Process - This study was conducted to determine critical gas metal arc welding variables and ways to optimize them - Y. T. Iç et al.
Predictive and Measurement Methods for Delta Ferrite Determination in Stainless Steels - The advantages and limitations of predictive measurement methods for δ ferrite are outlined - M. A. Valiente Bermejo
Susceptibility of IN740 to HAZ Liquation Cracking and Ductility-Dip Cracking - Conditions that lead to cracking susceptibility of nickel-based IN740 were simulated to determine an action for its prevention - J. E. Ramirez
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Welding Journal - April 2012