Parametric Optimization of AISI 1043 Steel Material Welded Joints by Shielded Metal Arc Welding

Abstract

Shielded metal arc welding (SMAW) is an arc welding process uses a consumable electrode covered with a flux to lay the weld. This welding process can be used for different material types. It was often used for heavy duty work involving iron and steel, like carbon steel, cast iron and nickel alloys. SMAW is one of the most widely used processes in industries to weld materials thickness from 5mm to 22mm sheet and plate respectively. This study was based on design of experiment using Taguchi method and desirability function analysis for multi-response optimization with three welding parameters namely; welding currents (115A, 135 A and 155 A), electrode diameter ( 2.5mm,3.25mm and 4.0mm ) and welding speed of 1.56mm/s.1.70mm/s and 1.86mm/s. The Taguchi method was used to analyze the effect of each welding process parameter on the welded strength and the optimal process parameters were obtained to achieve improved weld strength. The study includes selection of parameters, utilizing an orthogonal array (L9), conducting experimental runs, data analysis, determining the optimum combination, finally the experimental verification. Based on the important industrial applications, the experimental works were carried out on AISI 1043 carbon steel thickness 8mm steel plate by shielded metal arc welding with process parameters such as current, electrode diameter and welding speed. With all combination of welding process parameters the butt joint was selected. Based on conducted experiment the most significant control parameter was welding speed with maximum contribution of 56% whereas electrode diameter was the second parameter with 15% contribution. At optimized welding parameters; the maximum tensile strength was 407.8Mpa. As conducted by liquid penetrant test; the welding defects (porosity, under cut, lack of penetration and others) were observed on sample number 1,3,5,7 and 9 whereas samples numbers 2,4,6 and 8 are relatively defect free which was welded with optimum welding parameters. Based on the optimization results, all responses improved from initial value to the optimum parametric setting, which increased ultimate tensile strength (UTS) from 367MPa to 407.8MPa (11%) , hardness from 96.88HRB to 101HRB (4%) and overall composite desirability from 0.5996 to 0.8179 (36%) (A3B2C2). This parameter combination matched the results of the experimental value of tensile strength 410Mpa and hardness value of 103.6HRB with validation error is 0.536 and 0.025 respectively.Shielded Metal Arc Welding (Smaw) Is An Arc Welding Process Uses A Consumable Electrode Covered With A Flux To Lay The Weld. This Welding Process Can Be Used For Different Material Types. It Was Often Used For Heavy Duty Work Involving Iron And Steel, Like Carbon Steel, Cast Iron And Nickel Alloys. Smaw Is One Of The Most Widely Used Processes In Industries To Weld Materials Thickness From 5mm To 22mm Sheet And Plate Respectively. This Study Was Based On Design Of Experiment Using Taguchi Method And Desirability Function Analysis For Multi-Response Optimization With Three Welding Parameters Namely; Welding Currents (115a, 135 A And 155 A), Electrode Diameter ( 2.5mm,3.25mm And 4.0mm ) And Welding Speed Of 1.56mm/S.1.70mm/S And 1.86mm/S. The Taguchi Method Was Used To Analyze The Effect Of Each Welding Process Parameter On The Welded Strength And The Optimal Process Parameters Were Obtained To Achieve Improved Weld Strength. The Study Includes Selection Of Parameters, Utilizing An Orthogonal Array (L9), Conducting Experimental Runs, Data Analysis, Determining The Optimum Combination, Finally The Experimental Verification. Based On The Important Industrial Applications, The Experimental Works Were Carried Out On Aisi 1043 Carbon Steel Thickness 8mm Steel Plate By Shielded Metal Arc Welding With Process Parameters Such As Current, Electrode Diameter And Welding Speed. With All Combination Of Welding Process Parameters The Butt Joint Was Selected. Based On Conducted Experiment The Most Significant Control Parameter Was Welding Speed With Maximum Contribution Of 56% Whereas Electrode Diameter Was The Second Parameter With 15% Contribution. At Optimized Welding Parameters; The Maximum Tensile Strength Was 407.8mpa. As Conducted By Liquid Penetrant Test; The Welding Defects (Porosity, Under Cut, Lack Of Penetration And Others) Were Observed On Sample Number 1,3,5,7 And 9 Whereas Samples Numbers 2,4,6 And 8 Are Relatively Defect Free Which Was Welded With Optimum Welding Parameters. Based On The Optimization Results, All Responses Improved From Initial Value To The Optimum Parametric Setting, Which Increased Ultimate Tensile Strength (Uts) From 367mpa To 407.8mpa (11%) , Hardness From 96.88hrb To 101hrb (4%) And Overall Composite Desirability From 0.5996 To 0.8179 (36%) (A3b2c2). This Parameter Combination Matched The Results Of The Experimental Value Of Tensile Strength 410mpa And Hardness Value Of 103.6hrb With Validation Error Is 0.536 And 0.025 Respectively.