摘要
目的评价90SS和90SS-3Cr油管钢在H_2S-CO_2环境下的硫化物应力腐蚀开裂(SSCC)行为,并分析其断裂机理。方法利用四点弯曲实验和慢应变速率拉伸实验,结合显微组织分析、扫描电子显微镜分析技术,研究90SS和90SS-3Cr两种钢材在H_2S-CO_2环境下的应力腐蚀开裂行为和断口形貌特征。结果 90SS-3Cr钢的显微组织中存在更多的非金属夹杂物。经过720 h四点弯曲实验后,90SS和90SS-3Cr试样表面均未出现宏观及微观裂纹,表现出良好的抗硫化物应力腐蚀开裂能力。在慢应变速率拉伸实验中,当H_2S浓度由0增加至6 mol/L时,90SS-3Cr试样的断后伸长率δ、断面收缩率φ及断裂时间t分别下降了71.6%,69.6%,61.4%,远高于90SS钢的塑性损失(分别下降2.9%,52.5%,10.3%)。断口形貌分析表明,90SS-3Cr钢在较低浓度H_2S时就由塑性断裂向脆性断裂转变。结论随着H_2S浓度的升高,90SS和90SS-3Cr钢的塑性损失增加,抗SSCC能力均下降。相比90SS钢,90SS-3Cr钢对应力腐蚀开裂更为敏感。
Objective To evaluate the sulfide stress corrosion cracking（ SSCC） behavior of 90 SS and 90SS-3Cr tube steels in H_2 S/CO_2 environment,and determine the fracture mechanism. Methods The SSCC behavior and fracture morphologies of 90 SS and90SS-3Cr tube steels in H_2 S/CO_2 environment were investigated by using four point bend test（ FPB）,slow strain rate test（ SSRT）,microstructure and scanning electron microscope（ SEM） analysis. Results For 90SS-3Cr,more non-metallic inclusions appeared in the microscopic structure. After the FPB test for 720 hours,there were neither macroscopic nor microcosmic cracks on the surfaces of 90 SS and 90SS-3Cr specimens,which meant that they possessed a favorable SSCC resistance. However,the SSRT tests indicated that as the concentration of H_2 S increased from 0 mol/L to 6 mol/L,the elongation,the reduction of cross section and the fracture time of 90SS-3Cr steel decreased by 71. 6%,69. 6% and 61. 4%,which were much higher than that of 2. 9%,52. 5% and10. 3% of 90 SS steel respectively. The fracture morphology analysis showed that the fracture of 90SS-3Cr steel transformed from ductile fracture into brittle fracture at lower H_2 S concentrations. Conclusion The SSCC resistance of both 90 SS and 90SS-3Cr tube steels decreased with the rising of H_2 S concentration. 90SS-3Cr specimens were more prone to fracture than 90 SS steel.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2016年第2期1-7,共7页
Surface Technology
基金
山东省自然科学基金(ZR2010EM034)~~
