Abstract: Most of the various media in the petrochemical units are flammable, explosive, high-temperature and high-pressure medium. If there is any problem with the quality of the project, it is very likely to lead to safety accidents. Therefore,ensuring the construction project quality of the petrochemical units is crucial to the smooth operation of the device. And ensuring the welding quality of process pipelines for conveying various media is an important part of it. How to improve the production efficiency and welding quality of process pipe welding is an urgent technical challenge.In order to improve the welding quality and efficiency of the process pipeline of the 8.8 million tons/year residual oil hydrogenation unit, one international engineering project adopted the new technology of all-position automatic welding. Combining the application example of this project, this paper comprehensively expounds the key process points of all-position automatic welding from such aspects as the current situation of all-position automatic welding technology, the development of welding equipment, the performance test of different materials, the key points of operation process, quality requirements, efficacy comparison and engineering application. This technology has not only been well applied in international engineering, but also popularized and applied in many domestic engineering projects, which has effectively promoted the innovation and development of process pipeline welding technology.

Key words: all-position automatic welding technology, international large-scale petrochemical units, engineering application