Forged carbon steel threaded fittings - elbows, tees, couplings, caps, plugs and bushings - to ASME B16.11 in Classes 2000, 3000 and 6000, NPS 1/8 to 4, with NPT threads to ASME B1.20.1. Not every type is offered in every class.
Prices on request. Contact us for availability and quotations.
Forged carbon steel threaded fittings are the small-bore, high-pressure screwed range. ASME B16.11 covers their ratings, dimensions, tolerances, marking and material requirements, in sizes NPS 1/8 to NPS 4 (DN 6 to DN 100), with street elbows to NPS 2. They are forged, not cast, which is what separates them from the low-pressure malleable and cast ranges.
The class number is not a pressure. ASME B16.11 designates threaded fittings Class 2000, 3000 and 6000, and socket-welding fittings Class 3000, 6000 and 9000, and rates each by correlating it with a pipe schedule: a Class 2000 threaded fitting is rated as Schedule 80 (XS) pipe, Class 3000 as Schedule 160, and Class 6000 as XXS. The working pressure is then calculated for straight seamless pipe of equivalent material under the applicable piping code, including the allowances for erosion, corrosion and thread depth. Where a fitting has one threaded and one socket-welding end, the lower-rated end governs.
Threads are American National Standard Taper Pipe Threads (NPT) to ASME B1.20.1, internal and external. Materials are forgings, bar, seamless pipe or seamless tubular product conforming to ASTM A105, A182, A350, A234, A403, A420, A815, B366, B462 or B564; tees, elbows and crosses may not be made from bar stock. The types covered are 90 and 45 degree elbows, street elbows, tees, crosses, couplings, half-couplings, caps, square, hexagon and round-head plugs, and hexagon and flush bushings.
When ordering, state the fitting type, the size, the class, the end configuration - threaded, socket-welding or a combination - the material specification, and, critically, the thread form. A BSP-threaded fitting is not an ASME B16.11 fitting: NPT and BSP will start together and will not seal, because the flank angles differ (60 against 55 degrees) and so do the pitches at most sizes.
| Standard | ASME B16.11 - Forged Fittings, Socket-Welding and Threaded: ratings, dimensions, tolerances, marking and material requirements |
|---|---|
| Class Designations | Threaded ends: Class 2000, 3000 and 6000. Socket-welding ends: Class 3000, 6000 and 9000 |
| Rating Basis | The class number is not a pressure. Class 2000 threaded is rated as Schedule 80 (XS) pipe, Class 3000 threaded as Schedule 160, Class 6000 threaded as XXS; the working pressure is then computed for seamless pipe of equivalent material under the applicable piping code, including erosion, corrosion and thread-depth allowances |
| Size Range | Threaded elbows, tees and crosses: NPS 1/8 to 4 in Classes 2000, 3000 and 6000. Threaded couplings, half-couplings and caps: Classes 3000 and 6000 only - Class 2000, and NPS 1/8 in Class 6000, are not covered by the Standard. Street elbows: NPS 1/8 to 2, Classes 3000 and 6000. Plugs and bushings: NPS 1/8 to 4, usable to Class 6000 |
| Threads | American National Standard Taper Pipe Threads (NPT) to ASME B1.20.1, internal and external, with variation limited to one turn large or small from the working gauge |
| Materials | Forgings, bar, seamless pipe or seamless tubular products to ASTM A234, A403, A420, A815, B366, A105, A182, A350, B462 or B564. Tees, elbows and crosses shall not be made from bar stock |
| Fitting Types | 90 and 45 degree elbows, street elbows, tees, crosses, couplings, half-couplings, caps, square, hexagon and round-head plugs, hexagon and flush bushings |
| Combination End Fittings | Where a fitting has one threaded and one socket-welding end, the class is set by the end configuration with the lower rating |
| Construction of the Items Photographed | Forged black steel bodies - 90 degree elbows, tees, couplings, caps, hexagon plugs and bushings |
