逐层钻孔法测量P110级石油套管淬火残余应力分析

Analysis of Quenching Residual Stress of P110 Oil Casing by Incremental Hole Drilling Method

利用逐层钻孔法测试了直接淬火和水淬+空冷+水淬2种冷却工艺下的残余应力,分析了2种工艺下残余应力对裂纹产生和扩展的影响。结果表明:直接淬火工艺下,切向残余拉应力为229~281 MPa,轴向残余拉应力为191~237 MPa;水淬+空冷+水淬工艺下,切向残余应力为压应力,范围为-422^-185 MPa,轴向残余应力为拉应力,范围为90~190 MPa。与直接淬火工艺相比,优化冷却工艺使钢管切向应力变为压应力,轴向残余应力仍为拉应力但数值上减小,随孔深增加,轴向应力减小幅度趋于平缓,进而降低和缓解了钢管内微裂纹产生和扩展趋势。

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 analyzed. The results show that under the direct quenching the tangential and axial residual tensile stress are 229-281MPa and 191-237 MPa. Under the water quenching-air cooling-water quenching process, the tangential residual stress is compressive stress at -422 to -185 MPa and the axial residual tensile stress is 90-190 MPa. Compared to the direct quenching process, the tangential stress of optimizing cooling process is changed to compressive stress, the axial stress is still tensile stress but the numerical value is decreased, and the scale of the axial stress is reduced slightly with the increased depth, then the microcrack formation and propagation is relieved.