What are Flat Welding Flanges?
Flat Welding Flange has two types, Slip-on Flange & Plate Flange.
How to lap welding the flat welding flange?
Pipe need to insert into the flange ID to an appropriate position and then lap welding.
Advantage: It is easy for welding, and the total cost is competitive, so it is widely used.
According to the internal pressure calculation, the strength of the flat welding flange is about two-thirds of the corresponding butt welding flange, and the fatigue life is about one-third of the butt welding flange. Therefore, the flat welding flange is only suitable for pipeline systems with relatively low-pressure levels and low-pressure fluctuations, vibrations and spreading.

ANSI B16.5 150LB Slip-On Flange

Size | Pipe OD A | OD | Bolt Circle | Bolt Hole | Sealing Face | Thickness | ID | H | T2 |
Inch | DN | BC | B | R | RF | T1 |
1/2" | 15 | 21.3 | 90 | 60.5 | 16x4 | 35 | 1.6 | 11.5 | 22 | 30 | 16 |
3/4" | 20 | 26.9 | 100 | 70 | 16x4 | 43 | 1.6 | 13 | 27.5 | 38 | 16 |
1" | 25 | 33.7 | 110 | 79.5 | 16x4 | 51 | 1.6 | 14.5 | 34.5 | 49 | 17 |
11/4" | 32 | 42.4 | 115 | 89 | 16x4 | 63.5 | 1.6 | 16 | 43.5 | 59 | 21 |
11/2" | 40 | 48.3 | 125 | 98.5 | 16x4 | 73 | 1.6 | 17.5 | 49.5 | 65 | 22 |
2" | 50 | 60.3 | 150 | 120.5 | 18x4 | 92 | 1.6 | 19.5 | 61.5 | 78 | 25 |
21/2" | 65 | 76.1 | 180 | 139.5 | 18x4 | 105 | 1.6 | 22.5 | 77.5 | 90 | 29 |
3" | 80 | 88.9 | 190 | 152.5 | 18x4 | 127 | 1.6 | 24 | 90.5 | 108 | 30 |
4" | 100 | 114.3 | 230 | 190.5 | 18x8 | 157.5 | 1.6 | 24 | 116 | 135 | 33 |
5" | 125 | 139.7 | 255 | 216 | 22x8 | 186 | 1.6 | 24 | 143.5 | 164 | 36 |
6" | 150 | 168.3 | 280 | 241.5 | 22x8 | 216 | 1.6 | 25.5 | 170.5 | 192 | 40 |
8" | 200 | 219.1 | 345 | 298.5 | 22x8 | 270 | 1.6 | 29 | 221.5 | 246 | 44 |
10" | 250 | 273 | 405 | 362 | 26x12 | 324 | 1.6 | 30.5 | 276.5 | 305 | 49 |
12" | 300 | 323.9 | 485 | 432 | 26x12 | 381 | 1.6 | 32 | 327.5 | 365 | 56 |
14" | 350 | 355.6 | 535 | 476 | 30x12 | 413 | 1.6 | 35 | 359.5 | 400 | 57 |
18" | 450 | 457 | 635 | 578 | 33x16 | 533.5 | 1.6 | 40 | 462 | 505 | 68 |
20" | 500 | 508 | 700 | 635 | 33x20 | 584 | 1.6 | 43 | 513.5 | 559 | 73 |
24" | 600 | 610 | 815 | 749.5 | 36x20 | 692 | 1.6 | 48 | 616.5 | 663 | 83 |



1. How to make sure the raw material is real material which we need?
Firstly, we have our own casting foundry. We control our products’ quality start from raw material. The proportion of fixed raw materials, professional operation process, and detection of spectrometer imported from Germany.
2. Can we laser marking our logo or others on the pipe fittings?
Yes, it is acceptable.
3. Can we require custom packaging, such as color boxes, etc?
Yes, certainly. It depends on how many quantities do you need. It also will increase the total cost.
4. Can we cast our logo on the valves or print the logo on the handle sheath cover?
Yes, the Casting logo on the valves, depends on quantities. Our suggestion is laser marking on it. Print the logo on the handle sheath cover, it is free to design for our customer.
5. Are samples available to be sent for free?
Almost Yes, it depends on the value of the products. There are thousands of our products with different products and sizes. You can contact us for a particular answer.
