摘要
针对高压直流输电(HVDC)单极/双极接地形成的直流干扰对埋地管道造成的损伤,研究了负向干扰对X80M管线钢的损伤行为的影响。采用原位充氢的轴向拉伸试验方法研究了负向干扰电位、拉伸速率对X80M管线钢在NS4土壤溶液中的应力-位移曲线和氢脆敏感性指数的影响规律,采用扫描电子显微镜观察了拉伸试样主断口的断裂特征。研究发现:在-50^-150 V负向干扰电位范围内,X80M管线钢存在严重的氢损伤风险,但当干扰电位负于-80^-100 V时,X80M管线钢的氢脆敏感性有所降低;负向干扰电位越负,试验溶液的温度升高,从而影响X80M管线钢的氢脆敏感性;拉伸速率较低时,X80M管线钢的氢脆敏感性较大,呈现出脆性断口特征,但随着拉伸速率增大,脆性特征逐渐向韧性断口转变。原因分析表明:高压直流输电负向干扰会增加X80M管线钢的氢致开裂敏感性,负向干扰正于-80 V时比较显著,此种情况下管线钢呈现出明显的脆性断裂特征,因此工程中应监测高压直流输电负向干扰幅值,对负向干扰正于-80 V的高风险区域做好管道的排流措施。
Aimed at the damage of buried pipeline caused by DC interference of single pole/double pole grounding of HVDC,the effect of negative interference on the hydrogen induced damage of X80M pipeline steel was investigated.The effects of negative interference potential and tensile rate on the stress-displacement curve and hydrogen embrittlement sensitivity index of X80M pipeline steel in NS4 soil solution were studied by in-situ hydrogen-charged axial tensile test.The characteristics of the main fracture of tensile specimen were observed by SEM.It was found that there was a serious risk of hydrogen damage in X80M pipeline steel in the negative interference potential in the range of-50^-150 V,but when the interference potential was more negative than-80^-100 V,the hydrogen embrittlement sensitivity of X80M pipeline steel was reduced to a great extent.The more negative the interference potential was,the higher the temperature of the test solution was,thus affecting the hydrogen embrittlement sensitivity of X80M pipeline steel.When the tensile rate was low,the hydrogen embrittlement sensitivity of X80M pipeline steel was relatively higher,showing brittle fracture characteristics,but with the increase of tensile rate,brittle characteristics gradually changed to ductile fracture.The reason analysis showed that the negative interference of HVDC will increase the hydrogen induced cracking sensitivity of X80M pipeline steel,which is more significant when the negative interference is positive than-80 V.In such cases,the pipeline steel presents obvious brittle fracture characteristics.Therefore,the amplitude of negative interference of HVDC should be monitored in engineering practice,and the pipeline current drainage measures should be taken for the high risk area with negative interference more than-80 V.
作者
袁军涛
曹兴荣
黄岩岗
杨作祺
韩燕
付安庆
尹成先
YUAN Juntao;CAO Xingrong;HUANG Yangang;YANG Zuoqi;HAN Yan;FU Anqing;YIN Chengxian(State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials,CNPC Tubular Goods Research Institute,Xi′an,Shaanxi 710077,China;No.11 Oil Production Plant of PetroChina Changqing Oilfield Company,Qingyang,Gansu 745099,China;Yan′an Jiasheng Petroleum Machinery Co.,Ltd,Yan′an,Shaanxi 716004,China)
出处
《石油管材与仪器》
2020年第6期29-33,共5页
Petroleum Tubular Goods & Instruments
基金
国家重点研发计划“油气管道及储运设施损伤致灾机理与演化规律研究”(项目编号:2016YFC0802101)
中国石油天然气集团有限公司科学研究与技术开发项目“高强管线钢应力腐蚀开裂(SCC)全尺寸模拟及失效控制措施研究”(项目编号:2019D-5009-13)。
关键词
HVDC
负向干扰
氢脆
外加电位
拉伸速率
HVDC
negative interference
hydrogen damage
applied potential
tensile rate
