中俄东线站场X80异径三通低温韧性指标的确定

针对中俄东线站场低温环境(-45℃)用X80异径三通断裂控制问题,考虑三通的壁厚效应、结构的应力集中等影响,建立含缺陷X80异径三通有限元模型,应用BS 7910-2019《金属结构裂纹验收评定方法指南》和API 579-1/ASME FFS-1-2016《合于使用》中的失效评定方法,计算X80三通管体及焊缝的启裂韧性,通过断裂韧性与夏比冲击功关系式,确定了-45℃下X80三通夏比冲击韧性指标。结果表明:三通焊缝断裂韧性应大于37.79 MPa·m^1/2,夏比冲击功单个最低值不小于32.22 J;三通管体肩部内表面应力强度因子最大,其断裂韧性应大于42.46 MPa·m^1/2,夏比冲击功单个最低值不小于38.85 J。结合国内外管件标准要求,确定了中俄东线天然气管道工程用直径1422 mm×1219 mm的X80异径三通的低温韧性指标。(图5,表3,参19)

Determination of low temperature toughness index of X80 unequal-diameter tee in stations of China-Russia Eastern Gas Pipeline

To address the fracture control problem of X80 unequal-diameter tee used in China-Russia Eastern Gas Pipeline under low temperature environment(-45℃),the finite element model for X80 unequal-diameter tee with defects was built taking into consideration the influence of wall thickness effect and structural stress concentration of the tee.The crack initiation toughness of X80 tee body and welds was calculated by applying the failure evaluation methods of Guide to methods for assessing the acceptability of flaws in metallic structures(BS 7910-2019)and Fitness-For-Service(API 579-1/ASME FFS-1-2016).Charpy impact toughness index of X80 tee at-45℃was determined through the relation between fracture toughness and Charpy impact energy.The results show that the fracture toughness at the tee weld should be greater than 37.79 MPa·m^1/2,and the minimum value of each Charpy impact energy should not be less than 32.22 J.The stress intensity factor of the inner surface at the shoulder of the tee body is the largest,with the fracture toughness greater than 42.46 MPa·m^1/2,and the minimum value of each Charpy impact energy should not be less than 38.85 J.According to the requirements of domestic and foreign pipe fittings standards,the low temperature toughness index of the D 1422×1219 mm X80 unequal-diameter tee in ChinaRussia Eastern Gas Pipeline Project was determined.(5 Figures,3 Tables,19 References)