Plate Flat Welding Flange, commonly known as PL Flange, is one of the most widely used flat welding flanges in industrial piping systems. It is a cost-effective forged or fabricated flange designed for general pressure piping applications.
The flange is manufactured as an integrated flat plate structure with a machined bore slightly larger than the outside diameter of the connecting pipe. During installation, the pipe is inserted into the flange bore and fixed by fillet welding on the inner and outer sides, forming a permanent connection between the flange and pipeline.
The two mating flanges are tightened with bolts, compressing the gasket between the sealing faces to achieve reliable face sealing performance.
Note: The flange inner diameter (B) is determined by the wall thickness of the steel pipe and shall be specified by the user at the time of ordering.（Unit: mm）
| DN | NPS | Type/Class | Part No | D | K | L | Th | n | C | d1 | f |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15 | 0.5 | PL-150LB-SFT | XLXPL150SFT05 | 90 | 60.3 | 16 | M14 | 4 | 9.6 | 35.1 | 1.5 |
| 20 | 0.75 | PL-150LB-SFT | XLXPL150SFT075 | 100 | 69.9 | 16 | M14 | 4 | 11.2 | 42.9 | 1.5 |
| 25 | 1 | PL-150LB-SFT | XLXPL150SFT1 | 110 | 79.4 | 16 | M14 | 4 | 12.7 | 50.8 | 1.5 |
| 32 | 1.25 | PL-150LB-SFT | XLXPL150SFT125 | 115 | 88.9 | 16 | M14 | 4 | 14.3 | 63.5 | 1.5 |
| 40 | 1.5 | PL-150LB-SFT | XLXPL150SFT15 | 125 | 98.4 | 16 | M14 | 4 | 15.9 | 73 | 1.5 |
| 50 | 2 | PL-150LB-SFT | XLXPL150SFT2 | 150 | 120.7 | 18 | M16 | 4 | 17.5 | 91.9 | 1.5 |
| 65 | 2.5 | PL-150LB-SFT | XLXPL150SFT25 | 180 | 139.7 | 18 | M16 | 4 | 20.7 | 104.6 | 1.5 |
| 80 | 3 | PL-150LB-SFT | XLXPL150SFT3 | 190 | 152.4 | 18 | M16 | 4 | 22.3 | 127 | 1.5 |
| 100 | 4 | PL-150LB-SFT | XLXPL150SFT4 | 230 | 190.5 | 18 | M16 | 8 | 22.3 | 157.2 | 1.5 |
| 125 | 5 | PL-150LB-SFT | XLXPL150SFT5 | 255 | 215.9 | 22 | M20 | 8 | 22.3 | 185.7 | 1.5 |
| 150 | 6 | PL-150LB-SFT | XLXPL150SFT6 | 280 | 241.3 | 22 | M20 | 8 | 23.9 | 215.9 | 1.5 |
| 200 | 8 | PL-150LB-SFT | XLXPL150SFT8 | 345 | 298.58 | 22 | M20 | 8 | 27 | 269.7 | 1.5 |
| 250 | 10 | PL-150LB-SFT | XLXPL150SFT10 | 405 | 362 | 26 | M24 | 12 | 28.6 | 323.8 | 1.5 |
| 300 | 12 | PL-150LB-SFT | XLXPL150SFT12 | 485 | 431.8 | 26 | M24 | 12 | 30.2 | 381 | 1.5 |
| 350 | 14 | PL-150LB-SFT | XLXPL150SFT14 | 535 | 476.2 | 30 | M27 | 12 | 33.4 | 412.8 | 1.5 |
| 400 | 16 | PL-150LB-SFT | XLXPL150SFT16 | 595 | 539.8 | 30 | M27 | 16 | 35 | 469.9 | 1.5 |
| 450 | 18 | PL-150LB-SFT | XLXPL150SFT18 | 635 | 577.9 | 33 | M30 | 16 | 38.1 | 533.4 | 1.5 |
| 500 | 20 | PL-150LB-SFT | XLXPL150SFT20 | 700 | 635 | 33 | M30 | 20 | 41.3 | 584.2 | 1.5 |
| 600 | 24 | PL-150LB-SFT | XLXPL150SFT24 | 815 | 749.3 | 36 | M33 | 20 | 46.1 | 692.2 | 1.5 |
Simple structure and easy installation: The plate slip-on flange adopts a socket welding structure. Complicated groove machining of pipes is not required. Field installation, positioning and welding operations are easy to implement, delivering high construction efficiency.
Low manufacturing cost and cost-effective performance: Compared with weld neck flanges (WN Flange), plate slip-on flanges feature a simpler structure with less material consumption and lower processing costs. They rank among the most widely used flange types for general pressure pipelines.
The fillet-welded connection results in lower pressure resistance and fatigue resistance than weld neck flanges. Therefore, plate slip-on flanges are more suitable for medium and low-pressure piping systems, normal or moderate temperature working conditions, pipelines without severe vibration, and general industrial medium transportation systems.
