Certificate YAHANDA is the first company in China to research, produce and sell three-dimensional flexible welding fixtures. It is expected to hold 28 patents; among them, the core patents include: a universal pipeline welding fixture, a track-type flexible welding fixture, and a coaxial expansion fixture for inner holes. These have been applied in advance to military enterprises such as: China Shipbuilding Industry Corporation (716 Research Institute), Liuzhou Heavy Industry, China Construction Machinery Group (Changsha Yuelu District), Quanzhou Equipment Manufacturing Research Institute, Fuzhou University, Harbin University, Jinlong Bus, Huaxun Automobile, etc., as key units.