Numerical study on a thermal process in friction spot welding of Al-Zn-Mg-Cu alloy
A three-dimensional coupled thermo-mechanical model under consideration of local melting was developed to study the temperature distribution and thermal cycles during friction spot welding of Al-Zn-Mg-Cu alloy. The results indicate that the high-temperature region during welding was located in the sleeve cavity and the temperature gradient was higher in the thickness direction in the stir zone (SZ). At relatively high plunging depth and rotation speed, the peak temperature in the SZ was higher than the solidus temperature of Al-Zn-Mg-Cu alloy (532 °C). The peak temperature in thermal mechanically affected zone (TMAZ) was higher than the solution temperature (300 °C) but lower than the solidus temperature. The peak temperature in the heat-affected zone (HAZ) was higher than the aging temperature (170 °C). With the increase of the sleeve plunging depth, the peak temperatures in all the zones constantly increased. With the increase of the tool rotation speed, the peak temperature in the SZ and TMAZ first increased and then decreased, while the peak temperature in the HAZ constantly increased.
KeywordsFriction spot welding Temperature field Welding thermal cycle
The authors are grateful to be supported by the Science and Technology Plan Project of Guangzhou City (201807010068 and 201704030056), the Science and Technology Plan Project of Guangdong Province (2015B090922011), and the Implmenting Innovation-Driven Development Capacity Building Special Funds project of Guangdong Academy of Sciences (2018GDASCX-0113).