Buy Flanges Online in Australia
Pipe Flanges
A pipe flange is a disc-shaped fitting welded, screwed or bolted onto the end of a pipe, valve or vessel nozzle so two sections of pipework can be joined with bolts and a gasket instead of a permanent weld. It's the standard way to build a piping system that can be taken apart again — for a valve change, a pump swap, a line clean or a shutdown inspection — without cutting the pipe.
AIMS Industrial stocks 48 flange and flanged-fitting lines covering weld neck, slip-on, blind, screwed (threaded) and plate flanges, plus roll grooved flange adaptors, TTMA buttweld flanges and flanged hosetail fittings. Range is available in carbon steel, hot-dip galvanised steel, 316/316L stainless steel and aluminium, in the pressure ratings and standards outlined below. Our core flange range is supplied by AAP, an established Australian valve and pipe fitting brand, with flanged hose and grooved-pipe adaptor fittings from Dixon.
Quick Reference
| Type | Material options | Standard / rating | Typical use |
|---|---|---|---|
| Weld neck flange | Carbon steel, 316/316L SS | ANSI/ASME B16.5 Class 150–600 | High-pressure, high-temperature and cyclic-load process piping |
| Slip-on flange | Carbon steel, galvanised, 316/316L SS | AS 2129 Table D/E/H, ANSI B16.5 Class 150/300 | General industrial and water/irrigation piping — easier to align than weld neck |
| Blind flange | Carbon steel, 316/316L SS | AS 2129 Table D/E/H, ANSI B16.5 Class 150–600, PN16/21/35 | Blanking off a line end, a spare nozzle, or a test point |
| Screwed (threaded) flange | Carbon steel, galvanised | BSP or NPT thread, AS 2129 Table E/H | Low-pressure, small-bore piping where welding isn't practical |
| Plate (flat-faced) flange | Carbon steel | PN16, PN21, PN35 | Water, irrigation and fire-service pipework |
| Roll grooved flange adaptor | Galvanised steel | AS 2129 Table D | Converts a roll grooved pipe end to a bolted flange connection |
| TTMA buttweld flange | Aluminium | TTMA | Road tanker and bulk liquid transfer piping |
Types of pipe flanges we stock
Weld neck flanges
A weld neck flange has a long tapered hub that's butt-welded to the pipe, giving a smooth internal bore transition and spreading stress gradually into the pipe wall. It's the most robust flange type for high-pressure, high-temperature and cyclic (fatigue) service. AIMS stocks weld neck flanges to ANSI/ASME B16.5 Class 150, 300 and 600 in carbon steel.
Slip-on flanges
A slip-on flange slides over the pipe end and is fillet-welded at both the bore and the face. It's easier and quicker to align than a weld neck flange, with somewhat lower pressure and fatigue resistance — the most common flange for general industrial, water and irrigation pipework. Stocked in carbon steel, galvanised steel and 316/316L stainless.
Blind flanges
A blind flange is a solid disc, with no bore, that closes off the end of a pipe run, a spare vessel nozzle or a valve outlet. Used to blank off a line, hold a future connection point, or seal a nozzle during pressure testing. Stocked in carbon steel and 316/316L stainless, in raised-face and flat-faced options.
Screwed (threaded) flanges
A screwed flange threads directly onto a pipe with a matching external thread — no welding required. It suits smaller-bore, lower-pressure lines, or sites where hot work isn't practical. AIMS stocks screwed flanges in both BSP and NPT thread forms, in carbon steel and galvanised finishes.
Plate (flat-faced) flanges
Plate flanges are flat-faced steel flanges rated PN16, PN21 or PN35, used through Australian water, irrigation and fire-service pipework where a flat-faced mating surface is required (for example against cast fittings or valves).
Flanged adaptor fittings
Beyond flat pipe flanges, the range includes roll grooved flange adaptors (convert a roll grooved pipe end to a bolted flange face — see our roll groove fittings range for the matching couplings), a flanged combination nipple hosetail (bolts to a flange and terminates in a hosetail for camlock or hose connection), and Dixon TTMA buttweld flanges in aluminium for road tanker and bulk transfer piping.
Material options
- Carbon steel — our standard stocked material for general industrial, water, mining and fabrication service.
- Hot-dip galvanised steel — carbon steel with a galvanised coating for outdoor, water and corrosion-exposed installations.
- 316/316L stainless steel — for corrosive service, wash-down environments, marine exposure and food and beverage applications where carbon steel isn't suitable.
- Aluminium — used on Dixon's TTMA buttweld flanges for road tanker and bulk liquid transfer applications.
Match the flange material to the pipe and service — a mismatched flange in a bolted joint (for example a stainless flange bolted directly to an unprotected carbon steel one) can set up galvanic corrosion at the joint. If you're not sure what's suited to your fluid, pressure and environment, get in touch with our team before you order.
Standards, ratings and sizing — what to check before you order
Flange standards are not interchangeable. A flange built to one standard will not reliably bolt up to a flange of a different standard at the same nominal size — bolt circle diameter (PCD), bolt hole count and hole size all differ between standards, even when the pipe size and nominal pressure look similar. Always confirm the standard against the existing pipework, valve or fitting before ordering a replacement or new-build flange — measuring the bolt circle and counting bolt holes is the quickest way to identify an unknown flange on site.
AS 2129 — Table D, E and H
AS 2129 is the long-standing Australian dimensional standard for general industrial steel pipe flanges, organised into pressure "Tables" — our slip-on, blind and screwed range in this collection is built to the Table D, E and H series, which traces its lineage to the British BS10 flange standard. Table D suits lower-pressure general service, Table E is a common default across Australian industrial and water-adjacent piping, and Table H covers higher-pressure duty. Because table letter alone doesn't guarantee an exact dimensional match at every size, always confirm PCD and bolt count against the mating flange.
PN16, PN21 and PN35
"PN" (pressure nominal) ratings express a flange's nominal pressure rating in bar — PN16 is rated to a lower pressure than PN21, which is lower than PN35. Our plate and flat-faced flange range uses this system, consistent with the pressure classes used across Australian water industry pipework.
ANSI/ASME B16.5 — Class 150, 300 and 600
ANSI/ASME B16.5 is the American flange standard widely used on imported process equipment, skids and chemical/oil and gas plant in Australia. Class number denotes a pressure-temperature rating envelope, not a single fixed pressure — the higher the class, the higher the rated pressure at a given temperature, and the thicker and more heavily bolted the flange. Our weld neck, slip-on, blind and screwed range covers Class 150, 300 and 600, plus 316/316L stainless raised-face flanges in Class 150.
BSP vs NPT threads
BSP (British Standard Pipe) and NPT (National Pipe Thread) are different thread forms and are not interchangeable — a BSP-threaded flange will not seal correctly on an NPT-threaded pipe or fitting, and vice versa. Confirm which thread form your existing pipework uses before ordering a screwed flange. AIMS stocks screwed flanges in both.
Raised face vs flat face
A raised face (RF) flange has a small raised ring around the bore that concentrates bolt load onto the gasket — standard for steel-to-steel process piping. A flat face (FF) flange has no raised section, used where the mating component is a brittle-bodied item such as a cast valve body or a plastic/composite fitting, which could crack under the concentrated load of a raised face. Don't bolt an RF flange to a flat-faced cast component without checking the mating body's rating.
Applications and industries
AIMS Industrial's flange range is used across water and irrigation infrastructure, mining and mineral processing, general industrial and process piping, fabrication and maintenance workshops, and — through the Dixon TTMA and hosetail fittings — road tanker and bulk liquid transfer applications.
Brands we stock
AAP supplies the core of this range — weld neck, slip-on, blind, screwed and plate flanges in carbon steel, galvanised steel and 316/316L stainless. Dixon supplies the flanged adaptor fittings — roll grooved flange adaptors, TTMA buttweld flanges and the flanged combination nipple hosetail — for grooved-pipe and hose/camlock connections.
Companion ranges
- Gaskets — for the sealing ring or full-face gasket every flanged joint needs
- Flanged Fittings — flanged elbows, tees and reducers
- Roll Groove Fittings — grooved couplings to pair with our roll grooved flange adaptors
- Ball Valves — flanged and threaded valves for isolation and control
- Pipe Fittings — the wider fittings range for pipework builds and repairs
- Rubber Bellows — flexible flanged connections for vibration and movement
Order flanges from AIMS Industrial
Not sure which standard, pressure class or material suits your pipeline or plant? Our team can help you match a flange to your existing pipework or spec it for a new build. Call us on (02) 9773 0122, contact us online, or request a quote for a full flange schedule.
Flanges FAQ
What is a pipe flange used for?
A pipe flange lets you join two sections of pipe, or a pipe to a valve or vessel, with a bolted joint instead of a permanent weld — so the connection can be taken apart for maintenance, a component change or inspection without cutting the pipe.
What types of pipe flanges does AIMS Industrial stock?
Weld neck, slip-on, blind, screwed (threaded, BSP and NPT) and plate (flat-faced) flanges, plus roll grooved flange adaptors, a flanged combination nipple hosetail, and Dixon TTMA buttweld flanges — 48 lines in total across carbon steel, galvanised steel, 316/316L stainless steel and aluminium.
What's the difference between a weld neck and a slip-on flange?
A weld neck flange has a tapered hub that's butt-welded to the pipe for a smooth bore and the best fatigue resistance — the choice for high-pressure or cyclic service. A slip-on flange slides over the pipe and is fillet-welded at bore and face; it's quicker to fit but has lower pressure and fatigue resistance.
What is a blind flange used for?
A blind flange is a solid disc used to blank off the end of a pipe run, close a spare nozzle, or seal a line during pressure testing.
Do I need to weld a screwed (threaded) flange?
No — a screwed flange threads directly onto a pipe end with a matching BSP or NPT thread, so it can be fitted without hot work. It's best suited to smaller-bore, lower-pressure lines.
Are flanges from different standards interchangeable?
No. Flanges to different standards — AS 2129, ANSI/ASME B16.5, or a PN-rated flange — can have different bolt circle diameters, bolt counts and hole sizes even at the same nominal pipe size. Always confirm the standard, and check the bolt circle and bolt count, before ordering a replacement.
What does PN16, PN21 or PN35 mean on a flange?
PN stands for pressure nominal — the flange's nominal pressure rating in bar. PN16 is rated lower than PN21, which is rated lower than PN35. Our plate and flat-faced flange range uses this system.
What is an ANSI/ASME B16.5 Class 150, 300 or 600 flange?
ANSI/ASME B16.5 is the American flange standard used widely on imported process equipment in Australia. The class number sets a pressure-temperature rating envelope rather than a single fixed pressure — the higher the class, the higher the rated pressure at a given temperature, and the thicker and more heavily bolted the flange.
What's the difference between BSP and NPT threaded flanges?
BSP and NPT are different thread forms and aren't interchangeable — a BSP-threaded flange won't seal correctly against an NPT thread. Confirm which thread form your existing pipe or fitting uses before ordering.
How do I identify an unknown flange standard on an existing pipeline?
Count the bolt holes and measure the bolt circle diameter (the diameter of the circle running through the centre of each bolt hole). Together with the nominal pipe size, these narrow down the standard — our team can help confirm it if you're not sure, particularly if the pipeline is older or of unknown origin.
What is a roll grooved flange adaptor used for?
It converts a roll grooved pipe end into a bolted flange face, so a grooved-pipe system can connect to flanged equipment, a valve, or another flanged line. Pair it with a matching grooved coupling from our roll groove fittings range.
Does AIMS Industrial supply gaskets and bolts to suit these flanges?
Yes — see our gaskets range for the sealing ring or full-face gasket a flanged joint needs. For bolt and stud selection to suit your flange class and material, contact our team.