高压天然气管道不停输带压焊接可靠性研究

Study on Reliability of Under-pressure Welding of High Pressure Natural Gas Pipeline

高压天然气管道不停输带压施工中三通法兰组件的焊接工艺直接关系到施工过程及工程完工后的管道运行安全。三通法兰组件的焊接需要将不同材质的管子和管件(L360钢和Q345B钢)焊接在一起。为确保三通法兰组件焊接接头的强度及应力分布满足工程使用要求,确定合理的三通法兰组件焊接工艺是技术要点。设计了2种状态下的焊接实验,对L360钢、Q345B钢管子和管件进行带压静态焊接实验和带压动态焊接实验。焊接实验完成后采用有限元应力分析软件对焊接接头进行应力分析,结果显示,焊接接头中的应力分布满足工程使用要求。通过上述实验确定满足工程使用要求的焊接工艺参数:焊接材料选用J507,焊接电流为140~170 A,焊接电压为22~25 V,焊脚尺寸为14~16 mm。

The welding process of the three-way flange assembly in the under-pressure construction of the high-pressure natural gas pipeline is directly related to the pipeline operation safety in the construction process and after the completion of the project. The welding of the three-way flange assembly requires wehting of pipes and fittings of different materials （1.360 steel and Q345B steel） together. In order to ensure that the strength and stress distribution of ttle welded joint of the three-way flange assembly meet the engi- neering requirements,it is a technical key to determine the reasonable welding process of three-way flange as- sembly. The welding experiments are designed under two conditions, namely the under-pressure static weht- ing experiment and under-pressure dynamic welding experiment of I260 and Q345B steel pipes and fit- tings. After the completion of the welding experiments, the stress analysis of the welded joints is carried out by finite element stress analysis software. The resuhs show that the stress distribution in the welded joints satisfies the engineering requirements. Through the above ex- periments,the welding process parameters to meet the engineering requirements are determined： J507 welding materials, welding current of 140 to 170 A, welding voltage of 22 to 25 V,welding foot size of 14 to 16 mm.