Pipes of the large outer diameter series are connected to pipes of the small outer diameter series
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This post was last edited by Asuka Sky on 2022-3-2 at 14:13. I would like to ask the experts: How are pipes with a large outer diameter connected to pipes with a small outer diameter? For example, how to connect φ630*22 and φ508*20.62? Additional note: The pipeline is a medium-pressure steam pipeline with a pressure of 3.8 MPa and a temperature of 480°C.
In the case of a tee fitting, typically a hole is drilled in the large-diameter pipe, a pipe stub is welded onto it, and then the small-diameter pipe is connected. Otherwise, it is recommended to attach a blind flange to the large-diameter pipe; a hole is then made in the blind flange to connect the smaller pipe
The pipeline is a medium-pressure steam pipeline with a pressure of 3.8 MPa and a temperature of 480°C.
The connection between pipes of the large outer diameter series (imperial pipes) and those of the small outer diameter series (metric pipes) can only be achieved using flange connections (one imperial flange paired with one metric flange).
The large pipe is heated red with acetylene, made smaller, and then welded to the smaller-diameter pipe: lol
This post was last edited by Sihai Youxiantian on 2023-3-3 at 13:22. By checking the branch pipe connection table in the design documents, you can determine whether welding can be done directly, or if a tee needs to be cut and then welded on
This connection usually requires a custom fitting of a special size
Reference can be made to the GB50236 Code for Welding Construction of Industrial Piping; edge trimming should be performed on butt joints with unequal thicknesses. Steam pipes are considered pressure pipes, and flaw detection is required after welding.
For butt welding of pipes with different diameters, use the larger pipe when the wall thickness is significant; in cases where the wall thicknesses differ, a uniform transition is sufficient
The temperature and pressure are very high, and the wall thickness variations are too small to allow direct welding; flange connections can be used, or custom-made reduced-diameter pipes can be employed for welding