120和125钢级钻杆在NACE溶液中腐蚀行为研究

Study on Corrosion Behaviors of 120 and 125 ksi Drill Pipes in NACE Solution

将改进型27CrMo材料热处理成120和125钢级钻杆,采用电化学技术测试、浸泡试验和硫化物应力腐蚀试验,对比分析了两种钢级材料的腐蚀性能。结果表明:120钢级钻杆出现椭圆状腐蚀坑,而125钢级钻杆出现细长的腐蚀坑,腐蚀坑深度约为120钢级钻杆的两倍,且坑底出现腐蚀裂纹。120钢级钻杆通过了NACE TM 0177 A法D溶液抗硫化物应力腐蚀试验,而125钢级钻杆发生断裂,断裂方式为沿晶断裂,故125钢级钻杆抗硫应力腐蚀性能不佳。

The modified 27CrMo steel is turned into the 120 and 125 ksi drill pipes via the heat treatment process.The corrosion properties of the said two drill pipes are compared and analyzed by means of the electrochemical technology test tests,the immersion test and the sulfide stress corrosion test.The results show that the 120 ksi drill pipe develops oval corrosion pits,while the 125 ksi drill pipe develops thin an long corrosion pits the depth of which is two times that of the former,and at the bottom of which corrosive fractures are found.The 120 ksi drill pipe has passed the SSC test as per NACE TM 0177,Method A,Solution D,whereas the 125 ksi drill pipe has fractures in mode of intergranular fracture,which means that its anti-SSC property is poor.