4130 fittings
4130 tees: equal and reducing
Equal and reducing tees, and crosses, in AISI 4130, made seamless to ASME B16.9 dimensions for manifold headers and branch lines.
4130 tees split or join a high-pressure line. An equal tee has the same size on all three ends; a reducing tee has a smaller branch. We make them seamless in AISI 4130 to ASME B16.9 center-to-end dimensions, in Sch 80 to XXS and heavier walls, for manifold headers and branch lines at 7,500 to 15,000 psi.
Equal and reducing tees
The two in-line ends of a tee are the run and the third end is the branch, or outlet. An equal tee, also called a straight tee, has one size throughout. A reducing tee has a smaller branch and is written run by run by branch, for example 3 x 3 x 2 in. Each end is beveled to suit its own pipe, so the run can be XXS and the branch Sch 160 if that is how the line is built.
ASME B16.9 tee dimensions
| NPS | Run, C | Outlet, M |
|---|---|---|
| 1 | 1.50 (38) | 1.50 (38) |
| 1-1/2 | 2.25 (57) | 2.25 (57) |
| 2 | 2.50 (64) | 2.50 (64) |
| 2-1/2 | 3.00 (76) | 3.00 (76) |
| 3 | 3.38 (86) | 3.38 (86) |
| 4 | 4.12 (105) | 4.12 (105) |
| 5 | 4.88 (124) | 4.88 (124) |
| 6 | 5.62 (143) | 5.62 (143) |
| 8 | 7.00 (178) | 7.00 (178) |
Dimensions are the same for every wall thickness. A reducing tee keeps C of the run size; its outlet M follows the B16.9 table for the size pair.
Tees as targets in choke and kill lines
A tee turns flow through 90° more abruptly than any elbow, so in erosive service it is often used on purpose as a target: one run end is blanked, the flow turns into a pocket of fluid, and the cushion takes the impact instead of the wall. API Standard 53 asks for targets or fluid cushions on the flow side of 90° block ells and tees in choke and kill lines. Heavy-wall 4130 tees suit this use because the extra wall is erosion allowance. The trade-offs against long sweeps are covered in long sweep bends vs targeted tees.
Where the branch carries the flow into the run, the far wall of the run opposite the branch wears first. Order the run wall with that in mind, or ask for the tee to be made from a heavier section.
Crosses
A cross adds a fourth end opposite the branch. It is used in manifolds where two branches leave one header at the same point, and is made in AISI 4130 to ASME B16.9 dimensions with the same walls and heat treatments as the tees.
Heat treatment and sour service
Tees are heat treated with the rest of the order: normalized, or quenched and tempered to 75 ksi or 85 ksi minimum yield. For sour service, order 22 HRC maximum with a hardness survey to NACE MR0175 / ISO 15156-2, explained in 4130 for sour service.
Ordering
Reducing tee, 3 x 3 x 2 in, run XXS, branch Sch 160, ASME B16.9, AISI 4130 quenched and tempered, 75 ksi min yield, 95 ksi min tensile, EN 10204 3.1, 6 pcs
Frequently asked questions
How is a reducing tee written?
Run by run by branch, for example 3 x 3 x 2 in, with the wall of each end, for example XXS on the run and Sch 160 on the branch. The run keeps the center-to-end of the equal tee of the run size; the branch takes the outlet dimension that ASME B16.9 gives for that size pair.
Can a tee be used as a target?
Yes. With one run end blanked, a tee turns the flow 90° into a pocket of fluid that takes the impact instead of the wall. API Standard 53 asks for such targets or fluid cushions at 90° block ells and tees in choke and kill lines. See long sweep bends vs targeted tees.
Do you make crosses?
Yes. Four-way crosses in AISI 4130 are made to ASME B16.9 dimensions and the same walls and heat treatments as the tees.