Stainless Steel Slip-on Flange
S&S Stainless International, a trusted stainless steel flange manufacturer, offers ASME B16.5 stainless steel slip-on flanges known for their practicality and cost-efficiency. Designed for moderate pressure and temperature applications, these flanges are easy to install, making them ideal for industries like oil and gas, chemical processing, and water systems. Their simple slip-on design ensures reliable connections while reducing installation complexity and costs, making them a preferred choice for diverse piping systems.

Understanding Essential Dimensions for Slip-On (SO) Flanges
Accurate dimensions are critical for the successful installation and long-term reliability of any piping system component. Our stainless steel slip-on (SO) flanges are precision-engineered to specific industry standards, ensuring seamless integration with your pipes and other fittings. This page provides a comprehensive guide to the key dimensions of our stainless steel slip-on flanges, empowering you to select the exact specifications your project demands.
Product Specification
ASME B16.5
Class 150-600

ASME B16.5 Class 150
| Nominal Diameter | Pipe Diameter | O.D.of Flange | Diameter of Raised Face | Diameter of Bolt Holes Circle | Diameter of Bolt Holes | Numbers of Bolt Holes | Diameter of Bolt Holes(inch) | Flange Thickness | Hub Diameter | Through Hub Length (H) | |||
| DN | NPS | ID | D | G, R | K | L | B1-B4 | A | H1 | H2 | H3 | ||
| 15 | ½’’ | 21.3 | 90 | 35 | 60.5 | 16 | 4 | M14 | 11.5 | 30 | 48 | 16 | 16 |
| 20 | ¾’’ | 26.9 | 100 | 43 | 70 | 16 | 4 | M14 | 13 | 38 | 52 | 16 | 16 |
| 25 | 1’’ | 33.7 | 110 | 51 | 79.5 | 16 | 4 | M14 | 14.5 | 49 | 56 | 17 | 17 |
| 32 | 1 ¼’’ | 42.4 | 120 | 63.5 | 89 | 16 | 4 | M14 | 16 | 59 | 57 | 21 | 21 |
| 40 | 1 ½’’ | 48.3 | 130 | 73 | 98.5 | 16 | 4 | M14 | 17.5 | 65 | 62 | 22 | 22 |
| 50 | 2’’ | 60.3 | 150 | 92 | 120.5 | 18 | 4 | M16 | 19.5 | 78 | 64 | 25 | 25 |
| 65 | 2 ½’’ | 76.1 | 180 | 105 | 139.5 | 18 | 4 | M16 | 22.5 | 90 | 70 | 29 | 29 |
| 80 | 3’’ | 88.9 | 190 | 127 | 152.5 | 18 | 4 | M16 | 24 | 108 | 70 | 30 | 30 |
| 90 | 3 ½’’ | 101.6 | 216 | 140 | 178 | 18 | 8 | M20 | 24 | 122 | 71 | – | 32 |
| 100 | 4’’ | 114.3 | 230 | 157.5 | 190.5 | 18 | 8 | M20 | 24 | 135 | 76 | 33 | 33 |
| 125 | 5’’ | 139.7 | 255 | 186 | 216 | 22 | 8 | M20 | 24 | 164 | 89 | 36 | 36 |
| 150 | 6’’ | 168.3 | 280 | 216 | 241.5 | 22 | 8 | M20 | 25.5 | 192 | 89 | 40 | 40 |
| 200 | 8’’ | 219.1 | 345 | 270 | 298.5 | 22 | 8 | M20 | 29 | 246 | 102 | 44 | 45 |
| 250 | 10’’ | 273 | 405 | 324 | 362 | 26 | 12 | M24 | 30.5 | 305 | 102 | 49 | 49 |
| 300 | 12’’ | 323.9 | 485 | 381 | 432 | 26 | 12 | M24 | 32 | 365 | 114 | 56 | 56 |
| 350 | 14’’ | 355.6 | 535 | 413 | 476 | 29.5 | 12 | M27 | 35 | 400 | 127 | 57 | 79 |
| 400 | 16’’ | 406.4 | 600 | 470 | 540 | 29.5 | 16 | M27 | 37 | 457 | 127 | 64 | 87 |
| 450 | 18’’ | 457 | 635 | 533.5 | 578 | 32.5 | 16 | M30 | 40 | 505 | 140 | 68 | 97 |
| 500 | 20’’ | 508 | 700 | 584 | 635 | 32.5 | 20 | M30 | 43 | 559 | 145 | 73 | 103 |
| 550 | 22’’ | 559 | 750 | 641 | 692 | 35.5 | 20 | M33 | 46 | 610 | 149 | – | – |
| 600 | 24’’ | 610 | 816 | 692 | 749.5 | 35.5 | 20 | M33 | 48 | 664 | 152 | 83 | 111 |
ASME B16.5 Class 300
| Nominal Diameter | Pipe Diameter | O.D. of Flange | Diameter ofRaised Face | Diameter of Bolt Holes Circle | Diameter ofBolt Holes | Numbers ofBoltHoles | Diameter of Bolt Holes(inch) | Flange Thickness | Hub Diameter | Through Hub Length | |||
| DN | NPS | ID | D | G, R | K | L | B1-B4 | A | H1 | H2 | H3 | ||
| 15 | ½’’ | 21.3 | 95 | 35 | 66.5 | 16 | 4 | M14 | 14.5 | 38 | 52 | 22 | 22 |
| 20 | ¾’’ | 26.9 | 120 | 43 | 82.5 | 18 | 4 | M16 | 16 | 48 | 57 | 25 | 25 |
| 25 | 1’’ | 33.7 | 125 | 51 | 89 | 18 | 4 | M16 | 17.5 | 54 | 62 | 27 | 27 |
| 32 | 1 ¼’’ | 42.4 | 135 | 63.5 | 98.5 | 18 | 4 | M16 | 19.5 | 64 | 65 | 27 | 27 |
| 40 | 1 ½’’ | 48.3 | 155 | 73 | 114.5 | 22 | 4 | M20 | 21 | 70 | 68 | 30 | 30 |
| 50 | 2’’ | 60.3 | 165 | 92 | 127 | 18 | 8 | M16 | 22.5 | 84 | 70 | 33 | 33 |
| 65 | 2 ½’’ | 76.1 | 190 | 105 | 149 | 22 | 8 | M20 | 25.5 | 100 | 76 | 38 | 38 |
| 80 | 3’’ | 88.9 | 210 | 127 | 168.5 | 22 | 8 | M20 | 29 | 118 | 79 | 43 | 43 |
| 90 | 3 ½’’ | 101.6 | 229 | 140 | 184 | 22 | 8 | M20 | 30 | 140 | 81 | 45 | 45 |
| 100 | 4’’ | 114.3 | 255 | 157.5 | 200 | 22 | 8 | M20 | 32 | 146 | 86 | 48 | 48 |
| 125 | 5’’ | 139.7 | 280 | 186 | 235 | 22 | 8 | M20 | 35 | 178 | 98 | 51 | 51 |
| 150 | 6’’ | 168.3 | 320 | 216 | 270 | 22 | 12 | M20 | 37 | 206 | 98 | 52 | 52 |
| 200 | 8’’ | 219.1 | 380 | 270 | 330 | 26 | 12 | M24 | 41.5 | 260 | 111 | 62 | 62 |
| 250 | 10’’ | 273 | 445 | 324 | 387.5 | 29.5 | 16 | M27 | 48 | 321 | 117 | 67 | 95 |
| 300 | 12’’ | 323.9 | 520 | 381 | 451 | 32.5 | 16 | M30 | 51 | 275 | 130 | 73 | 102 |
| 350 | 14’’ | 355.6 | 585 | 413 | 514.5 | 32.5 | 20 | M30 | 54 | 426 | 143 | 76 | 111 |
| 400 | 16’’ | 406.4 | 650 | 470 | 571.5 | 32.5 | 20 | M33 | 57.5 | 483 | 146 | 83 | 121 |
| 450 | 18’’ | 457 | 710 | 533.5 | 628.5 | 32.5 | 24 | M33 | 60.5 | 533 | 159 | 89 | 130 |
| 500 | 20’’ | 508 | 775 | 584 | 686 | 32.5 | 24 | M33 | 63.5 | 587 | 162 | 95 | 140 |
| 550 | 22’’ | 559 | 840 | 641 | 743 | 42 | 24 | M39 | 66.5 | 640 | 165 | – | – |
| 600 | 24’’ | 610 | 915 | 692 | 813 | 42 | 24 | M39 | 70 | 702 | 168 | 104 | 152 |
ASME B16.5 Class 600
| Nominal Diameter | Pipe Diameter | O.D. of Flange | Diameter of Raised Face | Diameter of Bolt Holes Circle | Diameter of Bolt Holes | Numbers of Bolt Holes | Diameter of Bolt Holes(inch) | Flange Thickness | Hub Diameter | Through Hub Length | |||
| DN | NPS | ID | D | G, R | K | L | B1-B4 | A | H1 | H2 | H3 | ||
| 15 | ½’’ | 21.3 | 95 | 35 | 66.5 | 16 | 4 | M14 | 14.5 | 38 | 52 | 22 | 22 |
| 20 | ¾’’ | 26.9 | 120 | 43 | 82.5 | 18 | 4 | M16 | 16 | 48 | 57 | 25 | 25 |
| 25 | 1’’ | 33.7 | 125 | 51 | 89 | 18 | 4 | M16 | 17.5 | 54 | 62 | 27 | 27 |
| 32 | 1 ¼’’ | 42.4 | 135 | 63.5 | 98.5 | 18 | 4 | M16 | 21 | 64 | 67 | 29 | 29 |
| 40 | 1 ½’’ | 48.3 | 155 | 73 | 114.5 | 22 | 4 | M20 | 22.5 | 70 | 70 | 32 | 32 |
| 50 | 2’’ | 60.3 | 165 | 92 | 127 | 18 | 8 | M16 | 22.5 | 84 | 73 | 37 | 37 |
| 65 | 2 ½’’ | 76.1 | 190 | 105 | 149 | 22 | 8 | M20 | 29 | 100 | 79 | 41 | 41 |
| 80 | 3’’ | 88.9 | 210 | 127 | 168.5 | 22 | 8 | M20 | 32 | 117 | 83 | 46 | 46 |
| 90 | 3 ½’’ | 101.6 | 229 | 140 | 184 | 26 | 8 | M24 | 35 | 133 | 86 | 49 | 49 |
| 100 | 4’’ | 114.3 | 275 | 157.5 | 216 | 26 | 8 | M24 | 38.5 | 152 | 102 | 54 | 54 |
| 125 | 5’’ | 139.7 | 330 | 186 | 267 | 29.5 | 8 | M27 | 44.5 | 189 | 114 | 60 | 60 |
| 150 | 6’’ | 168.3 | 355 | 216 | 292 | 29.5 | 12 | M27 | 48 | 222 | 117 | 67 | 67 |
| 200 | 8’’ | 219.1 | 420 | 270 | 349 | 32.5 | 12 | M30 | 55.5 | 273 | 133 | 76 | 76 |
| 250 | 10’’ | 273 | 510 | 324 | 432 | 35.5 | 16 | M33 | 63.5 | 343 | 152 | 86 | 111 |
| 300 | 12’’ | 323.9 | 560 | 381 | 489 | 35.5 | 20 | M33 | 67 | 400 | 156 | 92 | 117 |
| 350 | 14’’ | 355.6 | 605 | 413 | 527 | 39 | 20 | M36 | 70 | 432 | 165 | 94 | 127 |
| 400 | 16’’ | 406.4 | 685 | 470 | 603 | 42 | 20 | M39 | 76.5 | 495 | 178 | 106 | 140 |
| 450 | 18’’ | 457 | 745 | 533.5 | 654 | 45 | 20 | M42 | 83 | 546 | 184 | 117 | 152 |
| 500 | 20’’ | 508 | 815 | 584 | 724 | 45 | 24 | M42 | 89 | 610 | 190 | 127 | 165 |
| 550 | 22’’ | 559 | 870 | 641 | 778 | 48 | 24 | M45 | 95 | 665 | 197 | – | – |
| 600 | 24’’ | 610 | 940 | 692 | 838 | 51 | 24 | M48 | 102 | 718 | 203 | 140 | 184 |
Navigating Our Stainless Steel Slip-on Flange Dimension Table
This table provides detailed measurements for selecting the correct stainless steel weld neck flange. You will find dimensions for:
- Nominal Pipe Size (NPS): The standard pipe size for which the flange is designed.
- Outside Diameter (OD) of Flanges: The total diameter of the flange itself.
- Raised Face (RF) Height: The height of the raised portion of the flange sealing surface (if applicable).
- Bolt Circle Diameter (BCD): The diameter on which the centers of the bolt holes lie.
- Number of Bolts & Bolt Hole Diameter: Specifies the quantity and size of bolts required for connection.
- Flange Thickness (T): The overall thickness of the flange.
- Hub Diameter: The diameter of the cylindrical or tapered projection from the flange.
- Through Hub Length: The length of the hub from the flange face to its end, indicating how far the pipe will extend into the flange.
Carefully match these dimensions to your project’s requirements to ensure a secure and leak-proof connection.
Engineered to Precision: Compliant with ASME B16.5 Standards
S&S Stainless International supplies high-quality stainless steel slip-on flanges manufactured in strict accordance with ASME B16.5 standards for pipe flanges and flanged fittings. Each flange is precisely produced to meet industry requirements for dimensions, tolerances, and construction quality. Our stainless slip-on flanges offer reliable performance, easy installation, and full compatibility with standard piping systems, making them an ideal choice for industrial applications requiring safety, durability, and consistency.
The Advantage of Precise Dimensions in Your Applications
Precise dimensions are particularly crucial for slip-on flanges due to their unique installation method. Accurate sizing ensures:
Slip on Flange Dimension
- Optimized Flow: Correct internal dimensions ensure smooth and efficient fluid transfer.
- Efficient Welding: Consistent hub and bore dimensions allow for cleaner, stronger, and more efficient welds, which are vital for the flange’s integrity.
- Simplified Installation: Standardized dimensions facilitate quicker and easier assembly, reducing installation time and costs.
- Long-Term Reliability: Consistent quality in sizing minimizes stress points and enhances the lifespan of the entire system.






