Effect of Plastic Deformation and H_2S on Dynamic Fracture Toughness of High Strength Casing Steel

作     者：曾德智 ZHANG Naiyan TIAN Gang HU Junying ZHANG Zhi SHI Taihe 

作者机构：State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation Southwest Petroleum University Luliang Field Operation DistrictPetro China Xinjiang Oil Field Company 

出 版 物：《Journal of Wuhan University of Technology(Materials Science)》 (武汉理工大学学报（材料科学英文版）)

年 卷 期：2015年第30卷第2期

页      面：397-403页

核心收录：

学科分类：0820[工学-石油与天然气工程] 08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 082002[工学-油气田开发工程] 

基　　金：Funded by the Construction of Key Disciplines for Young Teacher Science Foundation of the Southwest Petroleum University(No.P209) the Research Fund for the Doctoral Program of Higher Education(No.20105121120002) the National Natural Science Foundation of China(Nos.51004084 and 51374177) 

主　　题：sour gas fields high strength casing C110 steel plastic deformation H2S fracture toughness 

摘      要：The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD） casing and PD casing after being immersed in NACE A solution saturated with H2S（PD＋H2S）. Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness（JId） was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows： the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly.