油井管钢氢致开裂门槛值研究

THE THRESHOLD STRESS FOR HYDSOGEN-INDUCED CRACKING OF C90 TUBULAR STEELS

四种高强度油并管钢动态充氢时，进入试样的可扩散氢含量c0和充氢电流i成正比；而氢致断裂门槛应力σc与名义屈服强度σt之比和Inc0成正比，即σc／σt=A-BInc0．测量了四种钢在H2S中浸泡时进入试样的c0，求出相应的ic，用ic充氢时测出的门槛应力σc（H）／σt和H2S中应力腐蚀门槛应力σc（H2S）／σt相一致这表明，可用特定电流下的动态充氢来代替H2S应力腐蚀．

During dynamically charging four kinds of C90 tubular steels with hydrogen,the concentration of divisible hydrogen c0 is directly proportional to cathodic current i, and thenormalized threshold stress σc.(H)/σt decreases linearly with hi c0, i.e., σc(H)/σt=A-B ln c0.The concentrations of diffusible hydrogen in the steels during immersing in the H2S saturationsolution, c0*, have been measured. The values of σc(H)/σt during dynamically charging withic corresponding to c0* for the four steels are consistent with the threshold stress σc(H2S)/ctduring SCC in H2S solution. The result shows that the threshold stress during charging with asuitable current density ic can substitute for the threshold stress during SCC in H2S solution.