Threaded Flanges
Home»»Threaded Flanges
Threaded Flanges
Stainless Steel Threaded Flanges
Stainless Steel Threaded Flanges, also known as screwed flanges, connect to a pipe through matching internal and external threads — no welding required. This makes them quick to assemble and remove, and a safer choice around flammable materials where welding on-site is risky.
Because the joint relies on threads rather than a weld, threaded flanges are best suited to low-pressure, low-temperature pipelines and smaller pipe sizes, rather than the high-pressure or cyclic-loading services that call for a weld neck flange. Manufactured in SS 304, 304L, 316, 316L, 321, 347 and 904L, they combine easy installation with the corrosion resistance stainless steel is known for.
Threaded Flange Specification
| Dimensions | ANSI B16.5, ASME B16.47 Series A & B, MSS SP44, ASA, API-605, AWWA, custom drawings on request |
|---|---|
| Size Range | ½" NB (15 NB) to 48" NB (1200 NB) |
| Pressure Class | 150, 300, 400, 600, 900, 1500, 2500 |
| DIN Standards | DIN 2527, 2566, 2573, 2576, 2627, 2628, 2629, 2631, 2632, 2633, 2634, 2635, 2636, 2637, 2638, 2641, 2642, 2655, 2656, 2673 |
| BS Standards | BS 4504, BS 1560, BS 10 |
| Face Types | Flat Face (FF), Raised Face (RF), Ring Type Joint (RTJ) |
Types of Threaded Flanges
- Plate Threaded Flange
- Reducing Threaded Flange
- Forged Threaded Flange
- Square Threaded Flange
- Ring Type Joint (RTJ) Threaded Flange
- Class 125 Lightweight Threaded Flange
Material & Grades
Beyond stainless steel, threaded flanges are also manufactured in these materials and grade designations.
| Material | Grade Designation |
|---|---|
| Stainless Steel | ASTM A182, A240 F304, F304L, F304H, F316, F316L, F316Ti, F310, F310S, F321, F321H, F317, F347, F347H, F904L |
| Duplex & Super Duplex | ASTM/ASME A/SA182 F44, F45, F51, F53, F55, F60, F61 |
| Carbon Steel | ASTM/ASME A/SA105, ASTM A350, A181 LF2 / A516 Gr.70, A36, A694 F42, F46, F52, F60, F65, F70 |
| Low-Temperature Carbon Steel | ASTM A350 LF2, LF3 |
| Copper Alloy | ASTM SB61, SB62, SB151, SB152 · UNS C70600 (Cu-Ni 90/10), C71500 (Cu-Ni 70/30), C10100, C10200, C10300, C10800, C12000, C12200 |
| Nickel Alloy | ASTM SB564, SB160, SB472, SB162 · Nickel 200 (N02200), Nickel 201 (N02201), Monel 400 (N04400), Monel 500 (N05500), Inconel 600 (N06600), 601 (N06601), 625 (N06625), 800 (N08800), 825 (N08825), Hastelloy C276 (N10276), Alloy 20 (N08020) |
Threaded Flange Dimensions
Key dimensions in millimetres by pressure class, per ANSI B16.5.
| Class | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 |
|---|---|---|---|---|---|---|---|
| Diameter A (mm) | 30 | 38 | 38 | 38 | 38 | 38 | 43 |
| Diameter D (mm) | 90 | 95 | 95 | 95 | 120 | 120 | 135 |
| Thickness B min (mm) | 9.6 | 12.7 | 14.3 | 14.3 | 22.3 | 22.3 | 30.2 |
| Thickness B nom (mm) | 11.2 | 14.3 | 20.7 | 20.7 | 28.7 | 28.7 | 36.6 |
| Diameter G (mm) | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 |
| Diameter K (mm) | 60.3 | 66.7 | 66.7 | 66.7 | 82.6 | 82.6 | 88.9 |
| Height H min (mm) | 14 | 21 | 22 | 22 | 32 | 32 | 40 |
| Height H nom (mm) | 15.6 | 22.6 | 28.4 | 28.4 | 38.4 | 38.4 | 46.4 |
| Bolt Holes | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| Bolt Hole Diameter L (mm) | 15.9 | 15.9 | 15.9 | 15.9 | 22.2 | 22.2 | 22.2 |
| Stud Diameter (in) | 1/2 | 1/2 | 1/2 | 1/2 | 3/4 | 3/4 | 3/4 |
| Stud Length (mm) | 55 | 65 | 75 | 75 | 110 | 110 | 120 |
Applications of Threaded Flanges
Industries and equipment that use threaded flanges for low-pressure, weld-free connections.
- Oil & Gas Pipelines
- Chemical Industry
- Plumbing Systems
- Heating Systems
- Water Supply Systems
- Power Plants
- Paper & Pulp Industry
- Fabrication Industry
- Food Processing Industry
- Structural Piping
- Offshore Oil Drilling
- Petrochemicals
- Gas Processing
- Specialty Chemicals
- Pharmaceutical Equipment
- Sea Water Equipment
- Heat Exchangers
- Condensers
Frequently Asked Questions
What is a Stainless Steel Threaded Flange?
It is a flange with an internally threaded bore that screws directly onto a pipe with matching external threads, so it can be assembled without any welding.
When should threaded flanges be avoided?
Threaded flanges are not recommended for high-pressure, high-temperature or cyclic-bending applications — weld neck or slip-on flanges are a better fit for those conditions.
Why choose a threaded flange over a weld neck flange?
Threaded flanges are quicker and cheaper to install since no welding is required, which also makes them safer to use around flammable or combustible materials.
Which sizes and pressure classes are available?
We manufacture threaded flanges from ½" NB to 48" NB across pressure classes 150 to 2500.
Which face types are offered?
Flat Face (FF), Raised Face (RF) and Ring Type Joint (RTJ) threaded flanges are all available.
Need a Quote on Threaded Flanges?
Share your size, grade and pressure class requirement and our team will get back to you with pricing and availability.