American Socket Weld Flange (SW Flange)
- NPS: ½”~2”
- Standard: ASME B16.5
- Bolt Holes:4/8
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SW flange is a socket welding flange of American standard. The pipe is inserted into the concave area of the flange inner diameter and then fixed by brave fillet welding. This design is very suitable for small-diameter medium and low pressure systems ≤NPS 2″. The core feature is the inner diameter socket structure, which is connected to the pipe through a single-sided fillet weld. After welding, a 1.6mm expansion gap should be left to compensate for thermal deformation.
American Socket Weld Flange (SW Flange)
SW flange belongs to American Standard socket weld flange, inserted into the flange I.D. recessed area through the pipe and fixed by fillet welding, designed for small diameter (≤NPS 2″) low and medium pressure system.
The core feature is the I.D. Socket structure, which is connected to the pipe by a single side fillet weld, with a 1.6mm expansion gap after welding to compensate for thermal deformation.
Flange Ring
Sealing surface types include raised face (RF), flat surface (FF) and ring groove surface (RTJ), raised face height of 2.0~3.0mm, suitable for non-metallic gaskets or metal ring gasket.
The bolt hole layout follows ASME B16.5 standard, NPS 1” Class150 flange contains 4 bolt holes, center distance tolerance ±0.8mm.
Socket Interface
I.D. recess depth is 1.5 times the pipe O.D. (e.g. NPS 1” recess depth is about 25mm) to ensure weld stability after pipe insertion.
Weld Area:
In order to effectively connect the two parts, fillet welding is used. In order to prevent the root from producing unfused defects, the weld leg height should be ≥ 1.25 times the pipe wall thickness.
American Socket Weld Flange (SW Flange) Size
| NPS | DN | pressure | OD | Diameter of bolt hole center circle | Number of bolt holes × diameter | Flange thickness (T) | Depth of socket (S) |
| ½” | DN15 | Class 150 | 98 mm | 70 mm | 4×16 mm | 14 mm | 18 mm |
| ½” | DN15 | Class 300 | 114 mm | 82.5 mm | 4×19 mm | 18 mm | 22 mm |
| 1″ | DN25 | Class 150 | 120 mm | 89 mm | 4×16 mm | 16 mm | 25 mm |
| 1″ | DN25 | Class 300 | 133 mm | 98.5 mm | 8×19 mm | 20 mm | 30 mm |
| 2″ | DN50 | Class 150 | 165 mm | 127 mm | 4×19 mm | 19 mm | 38 mm |
| 2″ | DN50 | Class 300 | 190 mm | 152.5 mm | 8×22 mm | 24 mm | 45 mm |