Welding issues of concentric reducers

The welding of concentric reducers generally follows the standard requirements of the \"Code for Construction and Acceptance of Steel Piping Projects\" (GB 50235-2001). For the construction of high-neck flanges, reference can be made to the relevant provisions in the \"Quality Acceptance Standards for Welded Structures\" (GB 50236-98), which include requirements for high-neck flanges, welding procedures, and requirements for welders. The requirement for the length of the straight pipe section of the weld is generally determined based on the equipment’s design parameters; the specific length requirement needs to be determined by taking into account factors such as the dimensions, material, and pressure rating of the concentric reducer used. It is recommended to communicate with the design agency or equipment manufacturer before construction to confirm the specific requirements. Additionally, during the welding of concentric reducers, it is important to ensure the quality of the welds by preventing defects and controlling heat input, in order to guarantee the reliability and safety of the welds. -

Thank you so much for your extremely detailed reply; I’m really grateful{:1_90:}

You’re welcome! I hope it helps you! If you have any other questions, feel free to ask me at any time! -

Generally, GB50235 and GB50236 require the same thing: for DN≥150mm, the straight pipe length should be at least 150mm; for DN<150mm, it should be at least the outer diameter of the pipe, with a minimum of 100mm. The HG20801 standard requires basically the same things, only without the clause stating that the distance should be no less than 100 mm. Of course, there are other standards as well, but most of their requirements are similar

Direct welding is allowed, provided that the wall thickness of the high-neck flange matches that of the concentric reducer.