Welding process (1) open V-shaped groove geometry symmetrical two half pipes large bending machine press forming, machining process requirements groove butt welding, stitching space reserved. Design of welded joints are relatively weak link in welding engineering. Weld groove forms the internal quality control and quality of welded structures manufacturing has a very important role. Groove design must consider fusion than the base material, the welding space, welding position and overall economic efficiency and other issues. It should be calculated transverse shrinkage value Δ B. ΔB = 5.1Aω / δ + 1.27 d where Aω-- weld cross-section, mm; δ-- thickness, seamless pipe, mm; d-- weld root gap, mm. Once identified, the relationship ΔB and Aω, you can analyze the relationship based on both lists, seamless pipe plant, processing of data, seamless steel tube, to optimize the design, after Yun determine rectangular tube butt weld groove forms currently in China's steel industry, the use of circular steel pipe more, technology is relatively mature, there are more appropriate product standards and technical regulations for this application. When using circular steel pipe, some important parts of the building generally require the use of seamless steel tubes, but on the one hand due to the seamless expensive, seamless material, on the other hand due to the pipe's diameter can be made larger, the wall also can meet the design requirements, most of the buildings are still using welded components. As part of the grid structure using Longitudinal using part of seamless steel tubes. Seamless Specifications | Chun steel (certified) | seamless provided by the Tianjin Steel Co., Ltd. Chun Branch. Chun Branch Tianjin Iron and Steel Co. (www.tjsjkgt.com) (www.tjsjkgt.com) is Jinghai County of Tianjin, steel leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum meet customer needs. Chun Branch pipe in leadership with the staff warmly welcome all inquiries negotiations to create Chun steel better future.