Large diameter flanges to ASME B16.47, NPS 26 to 60, Class 75 to 900, Series A and Series B, weld neck and blind, forged or cut from plate in carbon, alloy and stainless steel.
- Standard: ASME B16.47, MSS SP-44, ASTM A105, ASTM A182, ASTM A350, ASTM A694
- Grades: A105, A350 LF2, A694 F52, A694 F60, A694 F70, F11, F22, F304, F316, F316L
- Certificate: EN 10204 3.1 with every order, 3.2 on request
Mejor Steel is the export agent for the mills that make your material: one contract, one delivery date, and the mill named on the quotation. How we supply
We reply within one business day, Monday to Friday 09:00-18:00 CST. Or write to info@mejorsteel.com / WhatsApp.
Specifications
| Outer diameter | 26" - 60" to ASME B16.47 |
|---|---|
| Schedule | Bore machined to match the pipe schedule for weld neck; blind has no bore |
| Length | Flange thickness and hub per ASME B16.47, Series A or Series B as ordered |
| Ends | Raised face (RF) or ring joint (RTJ) |
| Surface treatment | Black oxide, anti-rust oil, or machined finish |
| Manufacturing process | Forged and machined, or cut from plate and machined |
| Pressure rating | Class 75, 150, 300, 400, 600, 900 |
| Connection type | Butt weld to pipe (weld neck) or bolted closure (blind) |
ASME B16.47 Series A Class 150 dimensions
Series A, Class 150, NPS 26 to 48, in millimetres. Series A and Series B have different outside diameters and bolt circles and do not bolt together, so the series has to be stated on the enquiry. The table gives weld neck dimensions; blind flanges follow the same outside diameter, bolt circle and bolting, with a thickness calculated for the design condition.
| NPS | DN | Flange OD (mm) | Min. thickness (mm) | Bolt circle / PCD (mm) | Bolts | Bolt size | Hole dia (mm) | Raised face dia (mm) |
|---|---|---|---|---|---|---|---|---|
| 26 | 650 | 870.0 | 46.0 | 806.5 | 24 | M33 | 35.1 | 749.3 |
| 28 | 700 | 927.1 | 49.3 | 863.6 | 28 | M33 | 35.1 | 800.1 |
| 30 | 750 | 984.3 | 50.8 | 914.4 | 28 | M33 | 35.1 | 857.3 |
| 32 | 800 | 1060.5 | 53.8 | 977.9 | 28 | M39 | 41.3 | 914.4 |
| 34 | 850 | 1111.3 | 53.8 | 1028.7 | 32 | M39 | 41.3 | 965.2 |
| 36 | 900 | 1168.4 | 57.2 | 1085.9 | 32 | M39 | 41.3 | 1022.4 |
| 38 | 950 | 1238.3 | 57.2 | 1149.4 | 32 | M39 | 41.3 | 1073.2 |
| 40 | 1000 | 1289.1 | 60.5 | 1200.2 | 36 | M39 | 41.3 | 1124.0 |
| 42 | 1050 | 1339.9 | 60.5 | 1250.9 | 36 | M39 | 41.3 | 1193.9 |
| 44 | 1100 | 1416.1 | 63.5 | 1314.5 | 36 | M42 | 44.5 | 1244.6 |
| 46 | 1150 | 1466.9 | 63.5 | 1365.3 | 40 | M42 | 44.5 | 1295.4 |
| 48 | 1200 | 1536.7 | 66.5 | 1435.1 | 40 | M42 | 44.5 | 1358.9 |
Data to ASME B16.47 Series A; confirm against the project specification before fabrication. Series B (API 605), Class 300 to 900 and sizes above 48 in are quoted against the specification. Send the size, series, class and destination port and we will confirm availability and price within one business day.
Where Large Diameter Flanges Sit
ASME B16.5 covers flanges from NPS 1/2 to 24. Above that, flanges are made to ASME B16.47, which covers NPS 26 to 60 in Class 75, 150, 300, 400, 600 and 900. A 26 inch flange is not a scaled up 24 inch flange – it comes from a different standard with its own tables, so it has to be ordered as a B16.47 item and not as “B16.5, but bigger”. The sizes are used on transmission and terminal piping, tank farms, water and slurry mains and large bore equipment connections.
As a large diameter flange supplier, Mejor Steel supplies ASME B16.47 flanges from China in Series A and Series B, in the sizes, facings and grades set out on this page.
Series A and Series B Are Not Interchangeable
ASME B16.47 has two series. Series A came from MSS SP-44 and is the heavier pattern, with a larger bolt circle and more or larger bolts. Series B came from API 605 and is the lighter pattern. For the same size and class the two have different outside diameters, different bolt circles and different bolt counts, so a Series A flange will not bolt to a Series B flange and neither can be substituted for the other. The series is therefore not optional information – it must be stated on every order, and when a flange is being replaced in an existing line, the bolt circle and bolt count of the existing flange should be measured or the original drawing checked.
How Large Diameter Flanges Are Made
Large flanges are either forged and machined, or cut from plate and then machined. A blind in the larger sizes is very often a plate item, because a solid disc that size does not need a forged grain flow to carry its load. A weld neck in Series A is more likely to be forged, because it has a hub and a butt weld detail. The manufacturing route affects the test certificate and the examination method – plate material is normally ultrasonically examined – so it should be agreed at the order stage rather than assumed.
Facing, Bolting and Handling
Raised face and ring joint are the usual facings. As in ASME B16.5, the raised face height is 1.6 mm for Class 75, 150 and 300 and 6.4 mm for Class 400 and above, so a Class 300 and a Class 600 flange of the same size do not share a face height. Large diameter flanges take heavy bolting and long studs, and the bolt sets are usually ordered with the flanges so that the lengths and material match the class. Because of the weight, large flanges are supplied with lifting provisions agreed at the order stage, and are crated individually rather than palletised so that the faces and the ring grooves arrive undamaged.
What is the difference between ASME B16.47 Series A and Series B?
Series A originated from MSS SP-44 and is the heavier pattern, with a larger bolt circle and heavier bolting. Series B originated from API 605 and is the lighter pattern. For the same size and class they have different outside diameters, bolt circles and bolt counts, and the two are not dimensionally interchangeable – a Series A flange will not bolt up to a Series B flange.
Do I have to specify Series A or Series B when ordering?
Yes, above NPS 24 the series must be stated. Without it the flange cannot be confirmed, because the two series have different bolt circles and bolt counts. If you are replacing a flange in an existing line, the safest route is to give us the bolt circle and bolt count of the existing flange, or the original drawing.
What sizes and classes do you cover above NPS 24?
NPS 26 through 60 to ASME B16.47, in Class 75, 150, 300, 400, 600 and 900, Series A and Series B, weld neck and blind. Other patterns and facings can be quoted on request.
Can large diameter flanges be supplied as plate cut?
Yes, particularly blinds in the larger sizes. Plate material is ultrasonically examined and the manufacturing route is stated on the certificate. Where a hub or a butt weld detail is involved, a forged item is normally used. If the route matters to your specification, tell us at the enquiry stage.
Grades supplied and minimum properties
The grade fixes the minimum strength and the chemistry. The table below gives the requirements that separate the forged flange material grades ordered most often; the full composition and mechanical table for each grade is on its own page.
| Grade | Yield strength | Tensile strength |
|---|---|---|
| A105 (forged carbon steel) | 250 MPa (36,000 psi) | 485 MPa (70,000 psi) |
| F316 (forged stainless steel) | 205 MPa min (30,000 psi) | 515 MPa min (75,000 psi) |
The complete chemistry and mechanical table for each grade, with the notes that qualify it, is on the individual grade page – for example ASTM A105 flange. The stainless grade has the higher tensile requirement but the lower minimum yield strength, so the two are not interchangeable on the strength table alone. The pressure class sets the flange dimensions, so the grade does not set the wall.
Source: specified minimum yield and tensile strength for each grade, per ASTM A105 / ASME SA105 and ASTM A182 / ASME SA182. The standard named against each grade is the governing document.
Download Large Diameter Flange data sheet (PDF) One page: supply range, grades and key sizes, what to state on the enquiry, and the inspection documents that come with the order. The standard is the governing document.
What decides the price
There is no list price for flanges: the same drawing can be quoted at different numbers depending on seven things. Send them and the quotation comes back within one business day.
| Factor | Why it moves the price | What to send |
|---|---|---|
| Material grade | Carbon A105 is the baseline; F316, F51 and alloy grades cost more and take longer to source | The grade, or the line class |
| Size and pressure class | Weight and forging time rise with both | NPS and class |
| Facing | RTJ and special facings add machining | RF, FF or RTJ |
| Bore or schedule | A weld neck is bored to the pipe wall, so the schedule is part of the price | The pipe schedule |
| Quantity | Setup is spread over the pieces; a small lot carries more per piece | Pieces, or total weight |
| Inspection and certificate | EN 10204 3.2 and third-party inspection add cost and time | 3.1 or 3.2, and whether SGS, BV or TUV is required |
| Destination and Incoterm | Freight and packing follow the port | Destination port, FOB / CFR / CIF |
Reply within one business day. Send the seven items above with the quantity and the destination port. Send the specification or WhatsApp the specification.
Materials
- Forged carbon steel
- Plate carbon steel
- Forged alloy steel (Cr-Mo)
- Forged stainless steel
Typical applications
- Transmission pipeline stations and terminals
- Storage tank and terminal piping
- Water and slurry transmission mains
- Large bore compressor and pump connections
- Large diameter vessel and column nozzles
Inspection & testing
- Dimensional inspection per ASME B16.47
- Chemical and mechanical testing per ASTM
- PMI on alloy and stainless steel
- Hardness testing
- Ultrasonic examination of plate material
- Third-party inspection (SGS, BV, TUV) on request
| Packaging | Sea-worthy export packing: wooden cases or pallets, tagged with size, grade and heat number; corrosion protection on request. |
|---|---|
| MOQ | By piece - mixed sizes accepted; no minimum on standard items. |
| Lead time | Stock items: 5-10 days. Made to order: 3-5 weeks after order confirmation. |
Payment: T/T 30% deposit with the balance before shipment; L/C at sight also accepted. Final terms are confirmed on the quotation.
How we supply: sourced through partner mills; the producing mill is named on the quotation. How we supply sets out who is accountable for the order.
Need this product? Send the size, grade, quantity and destination port and we will reply with availability and pricing.
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