Project Overview: the phase I of Mengxi coal tosynthetic natural gas pipeline project includes three pipelines, one trunk line and two branches, passing through Tianjin and nine counties (cities, districts) in North China province. The pipeline is 366.417km long. The pipeline crosses 35 large and medium-sized rivers, 9 railways and 51 grade highways. The design pressure of the whole line is 10MPa, and the whole line adopts L485M steel pipe. Among them, Langfang Branch line starts from Bazhou off load station, with 914mm pipeline, 10MPa design pressure and 28.499km horizontal length. A new station (Yongqing off load station) and two monitoring valve chambers are set.

The welding of mainline is done by MX-4 and MX-5 spreads, and Xionggu pipeline automatic welding machine A-610 (double torch external welding machine) is adopted. The main line has been completed at the end of last year. Now the project is in the process of tie-in welding (as shown in the figure above). The tie-in adopts Xionggu pipeline automatic welding machines A-305 and A-300X. The spread 1 is the first spread who started to work. It took one week to install equipment and complete the examination. At the same time, the welding wires from different manufacturers are tested to acquire proper welding parameters. Due to the simple and easy operation of the welding machine and the continuous improvement of welders, all welder has passed the examination. Welded joints pass RT and AUT inspections either.

          Fig: the welder is using Xionggu A-305 pipeline automatic welder for joint welding

The project department strictly implements fine control and strong in the construction process. Three spreads of tie-in have used Xionggu pipeline automatic welding machine A-300X and A-305 in the same period, 98% qualified rate has been achieved.