摘要
中国已探明的天然气气田近一半为高含硫气田,面临着严峻的腐蚀问题,双金属复合管凭借其优良的耐蚀性能、力学性能及较高的性价比,在天然气集输领域得以应用。然而,在高含硫气田的环境中,双金属复合管时常会发生应力腐蚀开裂的现象。因此,研究复合管母材和焊缝焊接性能对安全至关重要。采用SYSWELD软件建立了热力学学耦合的双金属复合管有限元模型,并采用钻孔应变法测量了接头的残余应力,计算结果与试验测量结果吻合良好,验证了计算方法的妥当性,得到了双金属复合管多层多道焊的残余应力分布规律。结果表明,在中央截面上,基层应力为压应力,且随着距熔合线的距离增大而逐渐减小。焊缝侧轴向应力和环向应力呈帽状分布,为拉应力,衬层峰值应力高于基层,径向应力较小。熔合线附近应力较高,基层和衬层的应力机制不同,高应力区域集中在熔合线及过渡层附近,且易开裂。
Nearly half of China’s proven natural gas fields are high-sulfur gas fields,which faces severe corrosion challenges.Bimetal clad pipes are widely used in the natural gas transportation industry due to their excellent corrosion resistance,mechanical properties and cost-effectiveness.However,stress corrosion cracking is a common occurrence for bimetallic clad pipes in high-sulfur gas field environments.Therefore,studying welding properties of base material and welds of bimetallic clad pipes is crucial for safety.A thermomechanical-coupled finite element model of bimetallic clad pipes was established with SYSWELD software.Residual stresses of welded joints were measured by hole-drilling strain gauge method,the calculated results matched well with the experimental measurements,which validated adequacy of the computational approach,and distribution rule of residual stresses in multi-layer and multi-pass welds of bimetallic clad pipes was revealed.The results showed that the base layer experienced compressive stresses on the central cross-section,which decreased gradually with distance from the fusion line.On the weld side,axial and circumferential stresses exhibited a cap-shaped distribution with tensile stresses.The peak stress in the liner layer was higher than that in the base layer,while the radial stress was smaller.The stress near the fusion line was higher,and different stress mechanisms existed between the base layer and the liner layer.High-stress areas concentrated near the fusion line and transition zone were susceptible to cracking.
作者
叶丰
彭星煜
张丽江
冯梁俊
Ye Feng;Peng Xingyu;Zhang Lijiang;Feng Liangjun(Southwest Petroleum University,Chengdu 610500,China;China Petroleum Chuanqing Drilling Engineering Co.,Ltd.Safety and Environmental Protection Quality Supervision and Testing Research Institute,Chengdu 618300,China)
出处
《焊接》
北大核心
2023年第9期48-53,共6页
Welding & Joining
