Key facts
- Size range: 1/2″ – 24″ (ASME B16.5), larger on request
- Pressure class: CL150 – CL2500
- Face type: RF / RTJ / FF
- Standard: ASME B16.5, B16.47
- Material: ASTM A105, A350 LF2, A182 F316L
- Marking: Size, class, heat number, standard
Weld Neck Flange — Overview
The weld neck flange is the workhorse of a high-pressure system. The tapered hub transfers stress from the flange face into the pipe wall, so the joint stays tight under thermal cycling and vibration.
Because the bore matches the pipe inside diameter, there is no turbulence or pocket at the joint. That makes it the first choice for steam, hydrocarbon and high-class process lines.
We supply weld neck flanges face-machined and dimensionally checked to the standard, with each piece marked so it can be traced back to its material certificate.
Weld Neck Flange Specification
Standard range below. Anything outside it can be quoted on request — send the size, class and quantity you need.
| Standard | ASME B16.5 / ASME B16.47 Series A & B |
|---|---|
| Size range | 1/2″ to 24″ to B16.5; 26″ to 48″ to B16.47 |
| Pressure class | CL150, 300, 600, 900, 1500, 2500 |
| Face type | Raised face (RF), ring joint (RTJ), flat face (FF) |
| Bore | Matches pipe inside diameter |
| Material grades | A105, A350 LF2, A182 F304/L, F316/L, F11, F22 |
| Surface | Anti-rust oil or black paint; machined face protected |
| Marking | Size, class, standard and heat number on the rim |
| Packing | Fumigated wooden cases, seaworthy marking |
| Certificate | EN 10204 3.1 mill test certificate |
Material Grades We Stock
Carbon, low-temperature, alloy and stainless grades, all supplied with an EN 10204 3.1 mill test certificate.
Where It Is Used
The three project types that order this item most often.
Oil & Gas
Upstream and midstream lines, wellhead hook-ups and pipeline tie-ins where pressure classes run high.
Water & Desalination
Desalination plants, pumping stations and water transmission lines, in carbon or stainless steel.
Power & Process
Power plants, refineries and chemical process piping where heat resistance and traceability matter.
Send Us Your Specification
Size, standard, class and quantity is all we need. You will have prices, lead time and packing details within one working day.