GOST 12821 80 Weld Neck Flange is your good choice.Welding flange connection is to fix two pipes, pipe fittings or equipment to one welding first. Between the two welds, flange gaskets are added and bolted together to complete the connection. Welding is an important connection method for high-pressure pipeline construction. The welding flange connection is easy to use and can withstand greater pressure. Welding flanges are widely used in petroleum, chemical, natural gas, power stations, metallurgical pipelines and other fields.
International pipe flange standards mainly have two systems, namely the European pipe flange system represented by German DIN (including the former Soviet Union) and the American pipe flange system represented by American ANSI pipe flanges. In addition, there are Japanese JIS pipe flanges, but they are generally only used in public works in petrochemical plants, and they have little international impact. Now the pipe flanges of various countries are introduced below.
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Assemble the vertebral body and the large flange according to the requirements of the drawings, and then divide the large flange into 8 equal parts. For welding, because the flange is thicker and the groove is larger, segmented symmetrical and multi-layer welding is adopted. The weld strength is required to reach at least the strength of the base metal. The surface of the welding seam is flat and smooth, and there are no defects such as burn through, pores, weld leakage, slag inclusion, undercut, and insufficient weld. The remaining height is less than 2mm.
Always use J506 welding rod for manual surfacing and low current welding. Weld in strict accordance with the welding process. After each position is welded, use a level to check the deformation of the flange plane. While welding, use an air hammer to hammer the weld to achieve the effect of stress relief. GOST 12821 80 Weld Neck Flange is your good choice.