The Influence of Quenching Parameters on the Residual Stress of Ultra-High-Strength Aluminum Alloy Extrusions

The influence of quenching media on the residual stress of 7136 aluminum alloy extrusions was studied by the finite element simulation method. The results show a compressive stress at the component surface and tensile stress at the center. The maximum compressive and tensile stresses are 67.2 MPa and 82.6 MPa when quenching with 20 °C water. Increasing the water temperature to 80 °C can lead to a decrease in the maximum residual stress by 31.0% and 27.0%, respectively. When quenching in the PAG solution, the residual stress will decrease with the increased concentration. For example, the maximum compressive and tensile stresses will drop by 27.1% and 34.6% in 10% PAG solution compared with 0% solution (20 °C water). On the other hand, the increase in NaCl quenching solution will lead to a rise in the residual stress. When adding 20% NaCl from 0%, the compressive and tensile stress can increase by about 27.1% and 5.8%. It can be known from the results that the cooling rate of the alloy component under different quenching conditions will change, which causes the difference in the residual stress. It will be an effective method to control the residual stress through appropriate adjustment of quenching medium parameters.