Flanges & Gaskets - HORIZON AL-SAHM

Small bore, high pressure

Purpose: The pipe is inserted into a recessed socket and fillet welded around the outer edge only, leaving a smooth bore. Good strength and a leak-proof joint, and easier to align than a butt-weld.
Pressure class: ANSI 150, 300, 600, 900, 1500
Size range: 1/2″ to 2″, rarely above 4″
Faces: Raised face standard; flat face and RTJ available
Materials: Carbon steel (ASTM A105), stainless 304/316, alloy, duplex
Standards: ASME B16.5 and B16.11; also EN, DIN, JIS
Applications: Steam & CondensateHigh-Pressure WaterChemicalHydraulic
Note: Leave roughly 1/16″ (1.6 mm) between the pipe end and the socket shoulder when welding, to allow thermal expansion and avoid stress cracking.

Closes a line

Purpose: A solid disc with no bore, bolted between two flanges to close off a pipeline or pressure vessel. Used where a line will later be extended, tested or opened for inspection.
Pressure class: ANSI 150, 300, 600, 900, 1500, 2500
Size range: 1/2″ to 48″ and beyond, custom sizes available
Faces: Raised face, flat face, ring type joint
Materials: Carbon, stainless, alloy, duplex and specialty metals
Standards: ASME/ANSI, DIN, EN, JIS
Applications: Oil & GasPetrochemicalWater TreatmentPower Generation
Note: Frequently pressure-tested before despatch, and supplied with mill test certificates or EN 10204 3.1/3.2 documentation on request.

Low pressure, low cost

Purpose: Slides over the pipe and is fillet welded on both the inside and the outside face. No precise pipe-end preparation is needed, which makes it the quickest and cheapest of the welded flanges to fit.
Pressure class: ANSI 150, 300, 600, occasionally 900
Size range: 1/2″ to 48″; larger per ASME B16.47 Series A/B
Faces: Raised face most common; flat face for cast iron and non-metallic
Materials: Carbon, stainless, alloy and special alloys including Inconel and duplex
Standards: ASME B16.5 to 24″, B16.47 for 26″ and above; EN, JIS, DIN, GOST
Applications: Water LinesFirefightingHVACUtilities
Note: Not for ultra-high-pressure or critical duty. The weld integrity is lower than a butt-welded joint of the same size.

Opens often

Purpose: A two-piece assembly: a loose flange that rotates freely over a butt-welded stub end. Only the stub end touches the fluid, so the flange itself never sees the process.
Pressure class: ANSI 150, 300, 600, occasionally higher
Size range: 1/2″ to 24″
Faces: Flat face only. The seal is made on the back of the stub end
Materials: Corrosion-resistant stub end with a lower-cost carbon steel flange
Standards: ASME B16.5 and B16.47
Applications: Chemical PlantWater TreatmentFood & Pharmaceutical
Note: The free-rotating flange makes bolt alignment straightforward in tight spaces, and confines the expensive alloy to the stub end.

Highest duty

Purpose: A long tapered hub butt-welded to the pipe, transitioning wall thickness gradually. It distributes stress better than any other flange and gives the smoothest bore.
Pressure class: ANSI 150 through 2500
Size range: 1/2″ to 60″ and beyond, custom available
Faces: Raised face most common; RTJ for high pressure; flat face for low
Materials: Carbon (A105, A350), stainless 304/316/321, alloy, duplex, Inconel, Hastelloy
Standards: ASME B16.5, B16.47; also EN, DIN, JIS
Applications: High-Pressure SteamHydraulicCritical ProcessOffshore
Note: The choice where the joint sees vibration or thermal cycling. Supplied with dimensional and hydrostatic test reports and MTCs to EN 10204 3.1 or 3.2; NDT to project specification.

No welding

Purpose: Internally threaded so it screws directly onto a male-threaded pipe. Nothing is welded, which makes it the option where a hot work permit is difficult or a joint has to come apart again.
Pressure class: ANSI 150, 300, 600; rarely higher
Size range: 1/2″ to 4″
Faces: Raised face most common; flat face for cast iron; RTJ rare but available
Materials: Carbon (ASTM A105), stainless 304/316, forged and alloy steels
Standards: ASME B16.5; threads to ASME B1.20.1 (NPT) or ISO 7-1 (BSP)
Applications: Flammable ServiceTemporary LinesLow-Pressure WaterAir & Oil
Note: Threading limits both the size and the strength, which is why it is uncommon above 4″. It can be removed and refitted for maintenance.

Industrial-grade flanges for reliable sealing