Abstract:
Aluminium is a non ferrous corrosive resistance metal mainly used in automotive coolers, inter coolers and radiators.
They are the part of automobile vehicles and made from aluminium alloys. The joints in this application are created by
fusion welding process specifically Tungsten Inert Gas (TIG) and Pulsed current TIG (PCTIG) welding process. The working
temperature range of different coolers, radiators are 20° C to 300° C and pressure ranges from 2.5 bar to 3.5 bar. During
actual working of coolers, the weld joint experiences sudden high level and low level temperature changes. These will
create high thermal stresses in the joints. It leads to cracking in the weld region and create failure of the weld joints.
Various factors such as mechanical, metallurgical and thermal are responsible for cracking in the weld joints. Range of
solidification temperature is one of metallurgical factor, stress generation is mechanical factor and cooling rate of weld
metal is thermal factor for cracking. Houldcroft weldability test is employed to identify the cracking susceptibility (CS)
of the weld. The current investigation is intended to discover the effect of pulse TIG welding process parameters on the
mechanical properties and cracking susceptibility of precipitated aluminium Al-Mg-Si alloy. Diverse pulsed TIG welding
process parameters such as peak current (Ip), base current (Ib) and frequency (f) were investigated with the objective of
identify the tensile strength, yield strength and cracking susceptibility. The corresponding findings of optimum parameters
are 180 peak current (Ip), 60 A base current (Ib) and at 6 Hz frequency (f) with tensile strength of 185.55 MP, yield strength
156.62 MPa. The significant of each parameter for tensile strength are Ip, Ib, Ip*Ib, Ip*f and Ib*f. The corresponding
contributions in % are 14.56, 49.49, 12.26, 5.44, 12.15, 5.04, and 1.05 respectively. The statistical method such as Taguchi
was employed for experiment design. Weldability test (Fishbone test) was performed on standard specimen and the cracking
susceptibility index was identified. The cracking susceptibility index 5.26 % were observed with the value of 180 A of Ip,
80 A of Ib & 2 Hz of frequency (f).The results give an idea about the effect of pulsed TIG welding parameters on mechanical
properties and cracking susceptibility.
