INFLUENCE OF DOUBLE PULSE CONDITION ON WELDED SIZE AND TENSILE STRENGTH IN PULSE MIG WELDING

Abstract

In aluminum and aluminum alloys welding, alternating current has an effect of breaking an aluminum oxide film and cleaning the surface for better weld formation. The Aluminum and aluminum alloys have high thermal conductivity; thus, a process of controlling the weld pool size plays an important in ensuring the weld quality. Some factors influencing the shape of the weld pool can be due to the type of welding current, pulse condition... In which, an application of the MIG DOUBPULS function has a significant influence on the shape and quality of the weld. In this study, aluminum alloy A5052 and A6061 were welded by MIG welding process under changing pulse modes including pulse frequency Hz, time ratio and current ratio at pulse pin and pulse peak, using Er5356 welding wire with established welding current, voltage and speed. Results show that with changing the pulse mode, tensile strength as well as weld shape and size change. As the pulse frequency increases the penetration depth (h) and the weld width (b) decreases and then increases, while the weld height (c) increases and then decreases. The b and h increases, c decreases with an increase in the time ratio or current ratio at the pulse pin (%Tmin) and pulse peak (%Imin). The tensile strength of the welded samples is about 67.9 % to 88.8 % of the base metal tensile strength.This result will be a basis for making recommendations in aluminum and aluminum alloys welding by equipment with the MIG DOUBPULS function.