Slip on Flange
Slip on Flange
A slip on flange is a flange that is slipped over a pipe and then welded into place. It features a low hub, so the pipe can be placed into the flange before welding. Slip-on flanges are utilized in applications that demand easy alignment and assembly.
They are frequently employed in low-pressure, non-critical applications. The flange is usually welded both inside and outside to give adequate strength and prevent leaking.
Material Grades
Stainless Steel: ASTM / ASME SA403 GR WP “S” / “W” / “WX” 304, 304L, 304H, 309, 310H, 316L, 316H, 317, 317L, 321, 321H, 904, 904L, 347, 347H.
Duplex Steel: ASTM / ASME SA815 UNS NO. S31803, S32205, S32550, S32750, S32760.
Carbon Steel: ASTM / ASME A234 WPB, WPC, ASTM / ASME A860 WHY42, WHY46, WHY52, WH60, WPHY65 & WPHY70
Alloy Steel : ASTM / ASME A234 WP1, WP5, WP9, WP11, WP 12, WP22, WP23, WP91
Sizes
Slip-on flanges are available in a range of sizes to accommodate various piping systems:
- Nominal Pipe Size (NPS): Typically ranges from ½ inch to 24 inches.
- Diameter and Thickness: The outside diameter (OD) and thickness of the flange vary according to the pressure class and nominal size. Slip-on flanges have a lower hub height compared to weld neck flanges.
Pressure Ratings
Pressure ratings for slip-on flanges indicate the maximum pressure they can withstand at a given temperature. The most common pressure classes are:
- Class 150 (PN 20)
- Class 300 (PN 50)
- Class 400 (PN 64)
- Class 600 (PN 100)
- Class 900 (PN 150)
- Class 1500 (PN 250)
- Class 2500 (PN 420)
Slip-on flanges are generally used in lower pressure applications compared to weld neck flanges. The flange face types (e.g., flat face, raised face) also influence the pressure ratings.
Conclusion
When selecting a slip-on flange, it’s important to consider the applicable standard, material grade, size, and pressure rating for your specific application. Consulting the relevant ASME/ANSI, MSS, or ISO standards ensures compatibility and safety in your piping system. Slip-on flanges are especially suitable for lower pressure applications and offer ease of installation and alignment.
