Forged slip-on flanges for wholesale pipework
Slip-on flanges fit over the pipe and provide a welded connection to a bolted joint. Carbon-steel and stainless-steel options cover Class 150 and Class 300, with raised or flat gasket faces selected to match the mating flange.
| Flange type | Forged steel slip-on flange with a short hub |
|---|---|
| Material grades | ASTM A105 carbon steel; ASTM A182 F304L or F316L stainless steel |
| Dimensional specification | ASME B16.5, NPS 1/2–24 size series |
| Class selection | Class 150 and Class 300 |
| Gasket face | Raised face (RF) or flat face (FF) |
| Pipe connection | Smooth slip-on bore; pipe welded to the flange |
| Protection and quantity | Protective finish and flange piece count stated on each order line |
Find the nominal size, bolt circle or hole count.
| NPS (in.) | Flange OD (in.) | Bolt circle (in.) | Hole count | Hole diameter (in.) | Nominal bolt diameter (in.) |
|---|---|---|---|---|---|
| 2 | 6.00 | 4.75 | 4 | 3/4 | 5/8 |
| 4 | 9.00 | 7.50 | 8 | 3/4 | 5/8 |
| 6 | 11.00 | 9.50 | 8 | 7/8 | 3/4 |
| 8 | 13.50 | 11.75 | 8 | 7/8 | 3/4 |
| 12 | 19.00 | 17.00 | 12 | 1 | 7/8 |
| 24 | 32.00 | 29.50 | 20 | 1 3/8 | 1 1/4 |
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Bolt circle measures between the centers of diametrically opposite holes. Hole diameter provides clearance for the nominal bolt diameter. This selected Class 150 drilling table is separate from the flange bore, hub and thickness dimensions used on the order drawing.
NPS 2 identifies the connected pipe size. The Class 150 slip-on flange has a 6.00 in. outside diameter, a 4.75 in. bolt circle and four 3/4 in. holes for nominal 5/8 in. bolts. Those are separate measurements on the same part.
| Class | Flange OD (in.) | Bolt circle (in.) | Hole count × diameter (in.) |
|---|---|---|---|
| 150 | 6.00 | 4.75 | 4 × 3/4 |
| 300 | 6.50 | 5.00 | 8 × 3/4 |
An ASME flange, an AWWA flange and a DIN flange can share a nominal size description while using different dimensional systems. The standard and class or pressure designation identify the intended mating pattern.
Bolt-hole orientation on a fabricated spool fixes how connected elbows and instruments sit after assembly. The fabrication drawing identifies the hole orientation at the equipment connection before the slip-on flange is welded to the pipe.
Stud length and assembly clearance account for both flange bodies, the gasket and the selected nuts or washers. Clearance around equipment affects whether the hardware can be inserted and tightened after the spool is in place.
A raised face carries the gasket on the elevated annular surface around the bore. The mating face and specified gasket determine the contact arrangement; the raised ring is part of that connection geometry.
A flat face provides a seating plane across the flange face. Full-face gaskets include the bolt-hole area. Equipment specified with a flat-face connection retains that facing arrangement in the mating flange order.
Gasket faces are machined to the specified serration and surface finish. The selected gasket and project requirements set the permitted condition and coating at that contact surface.
The short hub slips over the pipe OD, allowing the flange position to be set before the welds are completed. The fabrication detail controls pipe-end position and welding around the hub and pipe opening.
A weld-neck flange has a tapered neck ending in a butt-weld connection. Its bore and end preparation match the pipe wall specification. A slip-on flange is not a direct replacement for that weld detail.
The weld-neck versus slip-on flange guide compares the joint details and fabrication work behind that choice.
A blind flange closes the flanged opening without a central flow bore. It uses the mating class, drilling and facing. A bored slip-on flange and a blind flange have different duties even when their bolt patterns match.
A lap-joint flange works with a separate stub end; the stub end provides the gasket face. The backing flange can rotate to align holes. That assembly differs from a slip-on flange welded directly to the pipe.
Checks cover the slip-on bore, hub geometry and body dimensions against the specified flange drawing. The pipe-fit opening remains distinct from the gasket-face diameter.
Drilling checks cover the number of holes, bolt circle and hole diameter. The hole mouths are deburred so bolts pass through cleanly without loose machining edges.
The face is examined for machining condition, scoring and handling damage. Protective coatings and packing materials preserve the specified gasket seating surface.
Grade, nominal size, class and facing identify the flange order. Our release review connects those entries with the material records and package descriptions, keeping carbon-steel and stainless-steel items distinct.
A joint made from two loose flanges uses two flange pieces. A valve or pump with an integral mating flange needs only the loose pipe-side flange on that purchase line. Gaskets and bolting retain their own quantities.
Packing separates the machined gasket surfaces so neighboring flanges do not rub against them. Pieces are grouped by size, class, facing and grade; package counts match the receiving list.
Our quotation identifies each flange type, material, class, facing and quantity. Batch quantities, production schedule, required records and shipping terms are set for the destination. Gaskets and bolting are priced as separate items.
Class 150 is a pressure-temperature rating designation, not a fixed 150 psi limit. The allowable rating follows the flange material group and operating temperature in the applicable standard. The approved piping specification sets the class for the order.
Yes. Gaskets, studs and nuts are listed separately from the flange pieces. The gasket material and bolting grade follow the service and mating-flange specification, with the required size and quantity identified for each assembly.
ASTM A105 identifies forged carbon-steel piping components. A plate-cut flange uses its own material specification and dimensional basis. A matching outline or bolt pattern alone does not establish A105 material identity.
Yes. A drawing can define a custom machining quotation. Its bore, hole positions, thickness and facing form the manufacturing scope. Altered dimensions are identified as the drawing specification, rather than being presented as an unchanged standard flange.
Send the nominal sizes, flange type, class, facing, material grade and piece counts with your delivery destination. Attach the equipment connection drawing or flange schedule for an itemized factory quotation.