AISI 4130 manifold fittings
4130 double-back elbows and standpipe goosenecks
Heavy-wall bends for the places where mud, cement and sand-laden flow turns: 3D elbows with a reinforced back, and the standpipe gooseneck that carries the mud line over to the rotary hose.
A double-back elbow is a 45° or 90° bend on a 3D radius, three times the nominal size, with its back, the outer wall where solids strike, made heavier than its inner wall and weld ends. A standpipe gooseneck is the large-radius 160° or 180° bend at the top of the mud standpipe that turns the line down to the rotary hose. We make both in AISI 4130, quenched and tempered, in 2 to 6 in, for mud, cement and manifold lines rated 5,000 to 15,000 psi.
Double-back elbows
When a line turns, the flow keeps going straight until the outer wall turns it, so sand, cuttings and cement wear that wall first. A double-back elbow puts extra metal exactly there. Combined with a 3D radius, twice that of a long radius elbow, the bend wears more slowly and evenly than a standard fitting of the same size, while its weld ends still match the pipe.
| Fitting | Bend radius | Wall at the back | Standard |
|---|---|---|---|
| Long radius elbow | 1.5 x nominal size | Same as the ends | ASME B16.9 |
| Double-back elbow | 3 x nominal size | Heavier than the ends | Maker's or buyer's drawing |
| Long sweep elbow | About 2.5 to 4 x nominal size | Heavier body all round | Maker's or buyer's drawing |
Where a choke or kill line must change direction, API Standard 53 asks for a targeted fitting or a bend with a radius of at least 10 times the pipe diameter; a 3D double back does not meet that by itself. See long sweep vs targeted tee.
Standpipe goosenecks
The gooseneck sits at the top of the standpipe on the derrick, joining the vertical pipe to the rotary hose that carries mud to the swivel or top drive. It is made with a large radius, and in two forms:
| Option | What it gives |
|---|---|
| 160° bend | Outlet angled down and out from the standpipe |
| 180° bend | Outlet pointing straight down |
| Top outlet | A branch at the top of the bend for a pressure gauge, a sensor or a kill connection |
| Integral bull plug | A blind extension at the top that takes the wear of the turning mud |
Ratings, ends and material
The rating follows the wall and the strength level: mud systems commonly run at 5,000 or 7,500 psi, and cement and manifold lines at 10,000 or 15,000 psi. Ends are beveled for butt welding to ASME B16.25 and matched to the pipe bore, or made with hammer union or hub ends. Both fittings are made from AISI 4130, quenched and tempered, and tempered to 22 HRC maximum for sour service under NACE MR0175 / ISO 15156-2.
Each fitting is stamped with size, wall, rating and heat number and ships with an EN 10204 3.1 certificate. Wall thickness checks at the back of the bend, hydrostatic testing, magnetic particle inspection and third-party witness can be added.
Ordering
Double-back elbow, 90°, 3D radius, 4 in, end bore to match 4 in XXS, butt weld to ASME B16.25, AISI 4130 quenched and tempered, 75 ksi min yield, for 10,000 psi, EN 10204 3.1, 6 pcs
Standpipe gooseneck, 160°, 5 in, with 2 in top outlet, butt weld ends for 5 in XXS, AISI 4130 quenched and tempered, for 7,500 psi mud service, EN 10204 3.1, 2 pcs
Frequently asked questions
What does double back mean?
The back of a bend is its outer wall, where solids carried in the flow strike as it turns. A double-back elbow has that wall made heavier than the inner wall and the weld ends, so it lasts longer in erosive mud, cement and sand-laden service.
What does 3D mean on a bend?
The bend radius, measured to the centerline, is three times the nominal pipe size. A 3 in 3D bend has a 9 in radius, against 4.5 in for a long radius (1.5D) elbow.
Why are goosenecks 160° or 180°?
The standpipe gooseneck turns the mud line over at the top of the derrick and down towards the rotary hose. The angle is chosen to suit how the hose hangs from that point on your rig: 160° leaves the outlet angled out from the standpipe, 180° points it straight down.
Are these fittings made to ASME B16.9?
Their weld ends match the pipe to ASME B16.9 and B16.25, but the bend radius, back wall and gooseneck geometry are made to the maker's or buyer's drawing, as for long sweep fittings.