EFFECT OF RESIDUAL STRESSES CAUSED BY THERMAL TREATMENT ON CREEP CRACK GROWTH RATE IN ALUMINIUM GAS CYLINDERS

摘要

Aluminum gas cylinders, which are in common use for various purposes, are susceptible to creep crack growth. Residual stresses introduced during the quenching process in aluminum gas cylinders contribute to the development of cracks. This may result in leakage or fracture of the cylinders. Finite element studies were conducted to evaluate the effect of the quenching process on through thickness inelastic strain and the residual stress distributions in the neck area of gas cylinders. Numerical modeling and experimental studies confirmed that a high level of tensile residual stresses exists on the inner surface of aluminum gas cylinders* neck which is susceptible to cracking. The relationship between the amount of residual stresses and cooling conditions was established. The obtained residual stress distributions were included in the calculation of the creep crack growth rates. It was shown that residual stresses caused by manufacturing processes have a significant effect on the creep crack growth rate.