According to the urban distribution and physical geographical characteristics of China, most of East China, South China and Southwest China are mountainous and hilly regions with a dense population and huge demand for oil and gas resources. In order to avoid urban planning and infrastructure construction, pipelines in mountainous areas will take an increasing proportion in pipeline construction.

For mountainous and hilly areas with worse environment, large residual stress of pipeline assembly, poor geological conditions and great construction difficulty, the failure rate of welded joints is higher than that of flat terrain, so it is necessary to conduct breakthrough research on welding equipment and technology. At the same time, the advantages of automatic pipeline welding lie in that the welding process parameters are easy to control, the welding process is stable, the weld mechanical properties are excellent, and the welding parameters can be collected and transmitted in real time. Considering the proportion of mountainous and hilly terrain in China, frequent disasters, large population and other national characteristics, full-automatic welding construction is crucial to ensure the safety of pipeline body, the public and the environment. It is necessary to study the automatic welding equipment and technology based on mountain terrain.

Chengdu Xionggu Jiashi Electrical Co., Ltd. completed the development of A-800E series 101 6mm and 1219mm caliber flexible internal welding machine for mountain pipeline in August 2022. From September to October 2022, the flexible internal welding machine for 1016mm caliber mountain pipeline was applied in the pipeline construction of ZY74-ZY77 and ZZ01-ZZ02 stake points of the "Zhonggui Line and Yuanba Puguang Pipeline Connection Project" in actual mountain terrain. Nearly 50 pipe joints were welded. The internal welding machine climbs up and down the slope in the pipeline within a gradient of 25 degrees, stops safely, and the passing performance and welding performance of 6D hot bends meet the actual construction requirements. The overall one-time qualified rate of the application section is 98%.