Evaluation of Stress Corrosion Resistance Properties of the Modified 15CrMoR(H) in H_2S Environment

To evaluate the hydrogen resistant properties of the 15 Cr MoR(H) with a new smelting process,according to NACE and National Standards,three tests including NACE standard tensile test,NACE standard bent-beam test and hydrogen induced cracking test were executed in saturated hydrogen sulfide(H₂S) environment. Stress-life mathematical model of this material was given by analyzing and fitting the results of tensile test. Test results show that the threshold σ_th of tensile test is 0.7R_eL(252MPa); the threshold nominal stress SCof bent-beam is higher than 4.5R_eL(1 620 MPa); and for HIC test,the crack length rate(CLR) is 4.40%,the crack thickness rate(CTR) is 0.87% and the crack sensitive rate(CSR) is 0.04%. Compared with the EFC standard,the safety margin of HIC test is 3.4,3.4 and 37.5 times,respectively. All the experimental results show that the new 15 Cr MoR(H) material has excellent H₂S environmental cracking resistance properties.