Abstract：In order to reduce the thermal stress and structural stress of P110 oil casing in the process of quench cooling, water quenching+air cooling+water quenching was proposed. The residual stresses of direct quenching and water quenching+air cooling+water quenching were determined by incremental hole drilling method and the residual stresses of two processes on crack formation and propagation was analysed. The results show that under the direct quenching the tangential and axial residual tensile stress are 229~281MPa and 191~237MPa. Under the water quenching+air cooling+water quenching process, the tangential residual stress is compressive stress at -422~-185MPa and the axial residual tensile stress is 90~190MPa. Compared to the direct quenching process, the tangential and axial stresses of proposed cooling methods are both decreased, then the microcrack formation and propagation is relieved.
2010, Vol. 45 
