Temperature and Time Dependent Analysis of Tungsten Inert Gas Welding of Low Carbon Steel Plate using Goldak Model Heat Source

In this study, temperature and time dependence analysis was carried out on Tungsten Inert Gas (TIG) Welding of AISI 1020 Low Carbon Steel Plate of 10 mm thickness. The TIG welding parameters deduced from design of experiment for current ranging from 96-213 A, voltage ranging from 16-25 V and gas flow rate ranging from 11-19 L/min was used as input variables for the welding experimentation and simulation using Finite Element Method (FEM) based on Goldak model heat source. There was proximity in the regression plot of temperature outputs for both the experimental and FEM predicted values. The temperature and time dependence transient thermal analysis was simulated for 20 seconds at welding speed of 1.5 mm/s in steps of 2.5 seconds for each heat source and the result revealed that at each increasing step, the heat distribution characterized by intense heat, phase transformation and alteration in mechanical properties gradually formed a spiral transient patterns from the weldment known as Heat Affected Zone (HAZ). Hence the longer the arc heat at a given weldment the wider the HAZ which result in high residual stress build-ups, undercut and other welding defects that hampers the welded component in service condition.

Keywords
Welding; Temperature; Time; Welding current; Heat distribution; Flat plate