煤层气井用抽油杆腐蚀疲劳寿命的影响因素  

Influence factors on corrosion fatigue life of sucker rods used in coalbed methane well

作　　者：李德君 王伟 庞斌 林伟 李文正 季亮 冯耀荣 LI De-jun WANG Wei PANG Bin LIN Wei LI Wen-zheng JI Liang FENG Yao-rong(CNPC Tubular Goods Research Institute, Xi＇ an 710077, China State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Materials, Xi＇an 710077, China Hancheng Branch, Petrochina Coalbed Methane Company Limited, Weinan 715400, China)

机构地区：[1]中国石油集团石油管工程技术研究院,陕西西安710077 [2]石油管材及装备材料服役行为与结构安全国家重点实验室,陕西西安710077 [3]中石油煤层气有限责任公司韩城分公司,陕西渭南715400

出　　处：《材料热处理学报》2017年第3期121-127,共7页Transactions of Materials and Heat Treatment

基　　金：国家科技重大专项(2011ZX05038)

摘　　要：通过显微组织分析、断口分析、有限元模拟分析、疲劳裂纹扩展速率测试和应力腐蚀试验研究制造因素、结构因素和材料强塑性对抽油杆腐蚀疲劳抗力的影响。结果表明,制造环节易导致抽油杆钢表面氧化脱碳以及镦粗段偏斜从而对抽油杆腐蚀疲劳寿命产生不利影响;抽油杆结构导致抽油杆镦粗段及前沿存在应力集中,且最大应力总是出现在杆体表面。表面氧化脱碳与应力集中的耦合作用使得抽油杆在腐蚀环境中快速诱发疲劳裂纹;在腐蚀环境中,提高抽油杆强度会导致疲劳裂纹扩展速率的增加,并且高强度抽油杆的腐蚀疲劳裂纹扩展曲线上会出现应力腐蚀平台;降低抽油杆的强度,提高抽油杆的韧性可以有效降低抽油杆在H_2S环境里的应力腐蚀开裂敏感性。Influence factors of manufacturing process,geometry configuration and the matching between strength and plasticity on corrosion fatigue resistance of sucker rods steel were studied by means of microstructure analysis,fracture analysis,finite element analysis,the testing of fatigue crack growth rate and stress corrosion testing. The results show that the surface decarburization and deflecting of upsetting section are easily formed during the manufacturing process; the geometry configuration of the sucker rod can cause the obvious stress concentration in the upsetting section and its cutting edge. The coupling of the surface decarburization and stress concentration results in a rapid inducing of fatigue crack in the corrosion environment. The corrosion fatigue crack growth rate increases with the increasing of strength of the sucker rod,moreover the curve of corrosion fatigue crack growth of high strength sucker rod has obvious stress corrosion platforms. The stress corrosion sensitivity of sucker rod steel can be effectively reduced by reducing the strength and improving toughness in the corrosion environment containing hydrogen sulfide.

关 键 词：抽油杆钢 腐蚀疲劳 应力集中 应力腐蚀 

分 类 号：TG162.75[金属学及工艺—热处理]