Properties of surfacing weld metals by MIG and TIG processes have been investigated using newly developed Al-Cu seamless type cored electrode wires of 1.2 mm in diameter. Three kinds of Al-Cu cored wires of 40, 45 and 70% Cu contents were tested on base plates of aluminum alloys of types A1050P (Al), A5083P (Mn-Mg-Al), A7075P (Cu-Mg-Zn-Al) and AC4B (Si-Cu-Zn, cast). The conclusions are as follows.
Hardness values at room temperature of HV220-260 on A5083P and A7075P and HV200-220 on AC4B were obtained in the transverse cross sections of the bead weld made by MIG and TIG processes.
The weld hardness increased in proportion to the Cu content in the weld metal on the A1050P base plate and hardness of HV300 was obtained in crack free condition with Cu content of 52%. Cracking in the weld metal occurred when the Cu content in the weld metal exceeded 54%.
Hardness measurement at elevated temperatures up to 400°C revealed a moderate decrease in hardness, but a rapid decrease at over 200°C.
Deposition rates of MIG and TIG processes are 30-40gr/min at 120-180A, 5gr/min at 100-140A, respectively. MIG process may be, recommended for weld surfacing, while TIG process for hardening of base metal.
Results of wear resistance test, pin-on-disk test, of weld metals made with Al-40Cu and Al-70Cu cored wires indicated improved resistance with increased surfacing hardness.