高钢级油套管用钢SSC抗力及开裂行为研究

发布时间：2018-05-17 23:31

  本文选题：高钢级油套管 + 硫化物应力开裂　； 参考：《西安石油大学》2017年硕士论文

【摘要】：本文在高钢级油套管用钢理化性能测试分析的基础上,利用NACE TM 0177-2013标准A法、四点弯曲法和双悬臂梁法分析P110、C110和125S三种高钢级油套管材料在硫化氢腐蚀环境下的应力开裂规律;运用Devanathan-Stachurski双电解池技术,研究高钢级油套管用钢的氢渗透行为及影响因素,探讨其SSC抗力与氢通量、氢含量之间的关系。结果表明:与P110钢相比,C110和125S钢的组织更加细小,夹杂物呈球形,晶粒内有较高密度的位错和弥散分布的碳化物;相比于P110、125S钢,C110钢硬度最低,冲击功最高,通过了NACE TM 0177-2013标准规定的抗SSC性能检测,具有良好的抗硫化物应力开裂性能。随着加载应力水平和阴极保护电位的升高,高强度油套管用钢的SSC敏感性增强;但随着温度升高,高强度油套管用钢的SSC敏感性明显降低,其在高温环境下的KISSC值更高,抗SSC性能增强。氢渗透行为研究的结果表明,在5%wt NaCl溶液和NACE TM 0177-2013标准A溶液两种溶液体系中,随着H_2S分压的增大、溶液pH值的降低和外加阴极电位的增大,高强度油套管用钢的稳态氢渗透电流密度增大,次表面氢浓度升高。高强度油套管用钢的次表面氢浓度和可扩散氢含量随温度升高、腐蚀时间的延长呈先上升后降低的趋势,并且其可扩散氢含量在腐蚀168 h后(24±3℃)达到最大值。在腐蚀环境一致条件下,具有典型Cr-Mo钢成分设计的C110油套管具有良好的抗SSC性能;成分设计与C110基本相同的125S油套管的强度增大,显微组织结构进一步细化,位错、晶界、亚晶界等亚结构数量明显增多,在金属内部存在的“氢陷阱”增多,导致其内部可扩散氢含量及次表面氢浓度增大,SSC敏感性增强。
[Abstract]:Based on the analysis of physical and chemical properties of high grade oil casing steel, the stress cracking law of three kinds of high steel oil casing materials P110C110 and 125S under hydrogen sulfide corrosion environment is analyzed by NACE TM0177-2013 standard A method, four point bending method and double cantilever beam method. The hydrogen permeation behavior of high grade oil casing steel and its influencing factors were studied by means of Devanathan-Stachurski double electrolytic cell technology. The relationship between SSC resistance and hydrogen flux and hydrogen content was discussed. The results show that the microstructure of C110 and 125S steels is smaller than that of P110 steel, the inclusions are spherical, there are high density dislocations and dispersed carbides in the grains, the hardness is the lowest and the impact work is the highest in comparison with P110125S steels. The NACE TM 0177-2013 standard has passed the test of SSC resistance, and has good resistance to sulfide stress cracking. With the increase of loading stress level and cathodic protection potential, the SSC sensitivity of high strength oil casing steel increases, but with the increase of temperature, the SSC sensitivity of high strength oil casing steel decreases obviously, and the KISSC value of high strength oil casing steel increases at high temperature. Enhanced anti-SSC performance. The results of hydrogen permeation behavior show that in 5%wt NaCl solution and NACE TM0177-2013 standard A solution system, with the increase of H _ 2S partial pressure, the pH value of the solution decreases and the applied cathode potential increases. The steady-state hydrogen permeation current density of high strength oil casing steel increases, and the hydrogen concentration of subsurface increases. The subsurface hydrogen concentration and diffusible hydrogen content of high strength oil casing steel increased with the increase of temperature, and the corrosion time increased first and then decreased, and the diffusible hydrogen content reached its maximum value at 24 卤3 鈩，

本文编号：1903371