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Sinopec News Network (Zhang Jianming and Ji Weimin) Recently, the new welding process of solid-core CO2 gas shielded welding (GMAW) developed by the machinery manufacturing company of Ningbo Engineering Company has been successfully applied in the manufacturing process of some low-temperature steel equipment of the Zhenhai ethylene project. This has solved some bottlenecks such as the longitudinal seams of large and ultra-large equipment and the closed circumferential seams of segmented cylinders that cannot be welded by the submerged arc automatic welding process. In 2005, the company took the lead in the domestic oil refining and chemical equipment manufacturing industries to develop and use the horizontal position submerged arc automatic welding process for vertical assembly. Although it solved the welding problem of efficient submerged arc automatic welding for most of the circumferential seams of large equipment, this welding process still cannot be used for the welding of the longitudinal seams of the equipment and the closed circumferential seams of the segmented cylinders. In 2008, the company began to develop a new welding process called solid wire CO2 gas shielded welding (GMAW) in order to effectively eliminate this welding bottleneck in the manufacturing of eight Cr-Mo steel coke drum equipment for the newly undertaken Indian Essar project. In more than half a year, the company's technical personnel have carried out technical exchanges with a number of well-known foreign welding material manufacturers and domestic and foreign gas suppliers. ； A number of welding experts from Hefei General Machinery Research Institute, Shanghai Gaoqiao Petrochemical Equipment Division and other units were invited to demonstrate the test plan, improve the test content, and conduct nearly a hundred sets of comparative tests through welding wire selection, mixed gas composition ratio, droplet transfer form, heat treatment temperature and welding process parameters, etc., and obtained the use of solid core welding wire CO2 gas Bulk shielded welding (GMAW) can meet the performance indicators required for Cr-Mo steel welding. Then, they conducted experimental research and evaluation of this welding process on low-temperature steel made of 09MnNiDR. They first conducted trial applications in the manufacturing of some low-temperature steel equipment in the Zhenhai ethylene project, and achieved a 100% first-time welding pass rate. According to industry professionals, the successful trial application of this new welding process will put an end to the controversy over whether flux-cored wire CO2 gas shielded welding (FCAW) can be applied to the main welds of pressure vessels in domestic specifications. It is of great significance to promote the application of CO2 gas shielded welding in the main welds of domestic low-alloy steel pressure vessels. It is understood that the company is currently summarizing experience, further improving the process, stricting process discipline, and strengthening process management in order to promote the early application of this new welding process.