3D Finite Element Modelling of Weld Bead Penetration in Tungsten Inert Gas (TIG) Welding of AISI 1020 Low Carbon Steel Plate

Authors : İkechukwu OWUNNA, Aniekan IKPE, J I Achebo

Pages : 96-105

Doi:10.26701/ems.441446

View : 18 | Download : 11

Publication Date : 2018-09-20

Article Type : Research Paper

Abstract :Weld quality is adversely influenced by bead penetration depth, as deeper penetration can improve the strength and load bearing capacity of weldments in service condition. Based on Design of Experiment insert ignore into journalissuearticles values(DOE);, an experimental design matrix having thirteen insert ignore into journalissuearticles values(13); center points, six insert ignore into journalissuearticles values(6); axial points and eight insert ignore into journalissuearticles values(8); factorial points resulting in twenty insert ignore into journalissuearticles values(20); experimental runs was generated for TIG welding current, voltage, gas flow rate L/min and temperature. Maximum bead penetration of 8.44 mm was obtained from the FEM simulation with corresponding input variables of 190 A, 19 V, 18 L/min and 298.44 o C compared to maximum bead penetration of 7.942 mm obtained from the welding experimentation with corresponding input variables of 155 A, 22 V, 15.50 L/min and 278.46 o C.   To clearly understand the rate of heat distribution across the as-welded plate, FEM bead penetration profiles were developed using Solid Works insert ignore into journalissuearticles values(2017 version); thermal transient analysis which revealed that the higher the temperature distribution the wider the Heat Affected Zones insert ignore into journalissuearticles values(HAZs); which are indications of phase transformations and alterations in mechanical properties of the welded metal which may lead to induced residual stresses if the welding parameters particularly the amperage is not controlled adequately. In addition, there was proximity in the trend of bead penetration from the regression plot where the FEM model had a coefficient of determination insert ignore into journalissuearticles values(R 2 ); of 0.9799 while R 2 of 0.9694 was obtained for the welding experimentation, indicating about 97.4% variance which in this context signifies that both bead penetration values can be adopted for real practical scenarios where deep weld bead penetrations are required.
Keywords : TIG welding, Bead penetration, Temperature, Heat distribution