Wellhead and manifolds
Studded tees, crosses and blocks
Forged blocks with API 6A ring grooves and studs in their faces instead of flanges: the compact tees, crosses and multi-outlet bodies that choke, kill and frac manifolds are built from.
A studded tee or cross is a forged block whose outlets are flat faces with an API 6A ring groove and tapped stud holes, so the mating flange bolts straight onto the block without a flanged hub of its own. Studded blocks are the building blocks of choke, kill, frac and test manifolds and of wellhead outlets. We make studded tees, crosses and multi-outlet blocks in AISI 4130, equal or reducing, in bores from 1-13/16 to 4-1/16 in, and larger to drawing, for 5,000 to 20,000 psi.
Types
| Type | Outlets | Used for |
|---|---|---|
| Studded tee | Three studded faces, or two studded and one flanged | Branches in manifolds and wellhead outlets |
| Studded cross | Four studded faces | Junctions in choke, kill and frac manifolds |
| Multi-outlet block | Five or more outlets on one body | Compact manifold headers |
| Target block | A blind face opposite the inlet | Changes of direction in erosive flow |
Outlets can be studded, flanged or a mix, and equal or reducing, all at one rated working pressure.
Ratings and material
Blocks are forged from AISI 4130 and quenched and tempered to the API 6A material designation the rating needs. Manifold makers commonly use 60K material for 5,000 and 10,000 psi blocks and 75K for 15,000 and 20,000 psi. Each block is made to the material class, temperature class and product specification level on your order; for sour service, to the hardness limits of NACE MR0175 / ISO 15156-2.
| Rated working pressure | Hydrostatic body test | Ring gaskets |
|---|---|---|
| 5,000 psi | 10,000 psi | R or RX |
| 10,000 psi | 15,000 psi | BX |
| 15,000 psi | 22,500 psi | BX |
| 20,000 psi | 30,000 psi | BX |
Body test pressures as set by API 6A for these ratings in the bore sizes listed here.
Dimensions
Center-to-face dimensions, outlet positions and bolt patterns are made to your manifold drawing, or to the dimensions your existing blocks use so the new block drops into the same layout. Bores can be inlaid with corrosion-resistant alloy and ring grooves inlaid where your order asks for it.
Studs and nuts can be supplied with the blocks, in the bolting material and coating your specification requires. Sour service bolting is chosen to the hardness limits that apply to it.
We make these parts to the API 6A requirements your order calls up: material, dimensions, tests and marking as specified. We do not hold an API license, so the parts do not carry the API Monogram. If your specification requires monogrammed equipment, the quotation says so plainly.
Ordering
Studded cross, 3-1/16 in 15,000 psi, four BX-154 studded outlets, studs and nuts, AISI 4130 75K, material class EE, temperature class P, PSL 3, EN 10204 3.1, 2 pcs
Studded tee, reducing, 4-1/16 in 10,000 psi run by 2-1/16 in 10,000 psi branch, BX-155 and BX-152 grooves, AISI 4130 60K, material class DD, temperature class U, PSL 2, EN 10204 3.1, 1 pc
Frequently asked questions
Why use a studded cross instead of a flanged one?
Studded faces need no flange hub, so the block is shorter center to face, lighter and stiffer, and a manifold built from studded blocks takes less room on a skid. The ring groove and bolt pattern are the same as the mating API 6A flange.
Can the outlets be different sizes?
Yes. Reducing tees and crosses have a smaller branch than run, for example 3-1/16 in run by 2-1/16 in outlets, all at one pressure rating.
Do you supply the studs and nuts?
Yes, as an option: alloy steel studs and heavy hex nuts to the material and coating your specification calls for, including sour service bolting.
What is a target block?
A tee or cross with a blind end facing the flow, sometimes filled with lead, used where a line turns so that solids strike a sacrificial face rather than the wall of a bend. Made to your drawing.