AISI 4130 fittings
4130 butt-weld fittings
Seamless heavy-wall fittings in AISI 4130 chromoly, made to ASME B16.9 dimensions or your drawing, heat treated and certified for high-pressure lines.
4130 butt-weld fittings are elbows, tees, reducers, caps and crosses made from AISI 4130 chromium-molybdenum steel and welded into high-pressure lines. We make them seamless, to ASME B16.9 center-to-end dimensions, with walls from Sch 80 to XXS and heavier sections ordered by outside and inside diameter, heat treated to the strength and hardness on your order for 7,500 to 15,000 psi service.
The range
4130 elbows
45°, 90° and 180°, long and short radius, ASME B16.9 dimensions.
LR 1.5D, SR 1D4130 tees
Equal and reducing tees and crosses to ASME B16.9 for headers and branches.
Sch 80 to XXS4130 reducers
Concentric and eccentric reducers to ASME B16.9 lengths, each end matched to its pipe.
Sch 80 to XXS4130 long sweep fittings
Long sweep elbows, 45° and 90°, with weld or union ends for erosive high-pressure lines.
2 to 6 in XXS, 15KDouble backs and goosenecks
3D double-back elbows with a reinforced back, and 160° and 180° standpipe goosenecks.
2 to 6 in, 5K to 15K4130 integral fittings
One-piece tees, crosses, ells and laterals with hammer union ends, no welds.
FIG 602, 1002, 1502The pipe they join is on the 4130 seamless pipe page; hammer unions, swivels and the rest of the flowline range are under flowline equipment.
There is no ASTM fitting grade for 4130
Carbon and alloy steel butt-weld fittings are normally bought to ASTM A234, whose grades run from WPB through WP11, WP22, WP5 and WP91. None of them is 4130, and the forged-fitting specification ASTM A182 has no 4130 grade either. A 4130 fitting is therefore ordered by naming the steel, AISI 4130 (UNS G41300), and writing the rest into the order or the equipment maker's own material specification:
| Item | Example |
|---|---|
| Material | AISI 4130 (UNS G41300), seamless |
| Dimensions | ASME B16.9 center-to-end, end OD and wall to match the pipe |
| Heat treatment | Quenched and tempered, or normalized |
| Strength | 75 ksi min yield and 95 ksi min tensile, or 85 ksi and 110 ksi for 15,000 psi |
| Hardness | 22 HRC max for sour service |
| Impact and NDE | Charpy at the temperature class; UT or MT where the order needs it |
| Certificate | EN 10204 3.1 |
Dimensions: ASME B16.9 with heavy walls
ASME B16.9 fixes the center-to-end dimensions and the outside diameter at the weld bevel, so a fitting lines up with pipe of the same nominal size. The wall follows the pipe it is welded to, and B16.9 holds the wall at any point to at least 87.5% of the nominal wall. For XXS and heavier walls, and for lines ordered by OD and ID, we make the fitting to the same center-to-end with the wall and bore your drawing gives. Short radius elbows and 180° returns follow the ASME B16.28 tables.
The dimension tables are on each fitting's page: elbows, tees and reducers.
Pressure ratings
A butt-weld fitting has no pressure class of its own. ASME B16.9 rates it as straight seamless pipe of the same material and wall, so a 4130 fitting is rated with the line it goes into, through the wall and the strength level ordered. We make 4130 fittings for lines with working pressures of 7,500, 10,000 and 15,000 psi, and higher to drawing. The difference between working, test and cold working pressure is explained in pressure ratings for 4130 pipe and fittings.
Weld ends
Ends are beveled to ASME B16.25: a 37.5° bevel with a 1/16 in (1.6 mm) land for walls up to about 0.88 in (22 mm), and a compound bevel, 37.5° then 10°, for heavier walls, which keeps the weld volume down on XXS and heavy OD by ID sections. Where the fitting and the pipe have different bores, tell us the mating inside diameter and the end is bored to match.
Heat treatment, hardness and tests
| Property | How it is set | Checked by |
|---|---|---|
| Strength | Heat treatment: normalized, or quenched and tempered to the ordered level | Tensile test, in house |
| Hardness | Tempering, with 22 HRC max for sour service | Hardness test, in house |
| Grade | Material bought with mill certificates, heat number stamped | PMI and chemical analysis |
| Toughness | Heat treatment and steel cleanliness | Charpy test at an accredited lab |
| Soundness | Seamless construction | UT and MT at an outside lab, where ordered |
| Dimensions | B16.9 or drawing | Inline and final dimensional inspection |
For H2S service, order the fittings to NACE MR0175 / ISO 15156-2 with 22 HRC maximum and a hardness survey. See 4130 for sour service.
Ordering
90° long radius elbow, 3 in, XXS, butt weld to ASME B16.25, AISI 4130 quenched and tempered, 75 ksi min yield, 95 ksi min tensile, 22 HRC max, EN 10204 3.1, 12 pcs
Concentric reducer, 4 in XXS x 3 in XXS, ASME B16.9 length, AISI 4130 quenched and tempered, 85 ksi min yield, 110 ksi min tensile, for 15,000 psi, EN 10204 3.1, 4 pcs
Frequently asked questions
Are 4130 fittings made to ASTM A234?
No. ASTM A234 has grades such as WPB, WP11, WP22, WP5 and WP91 but no 4130 grade, and ASTM A182 has none either. 4130 fittings are ordered by naming the steel, AISI 4130 (UNS G41300), with the heat treatment, strength, hardness and tests, while the dimensions follow ASME B16.9 or your drawing.
Can you match the fittings to our pipe?
Yes. Tell us the pipe OD and wall or ID at each end, and the strength level and hardness of the pipe. The fitting is made to the same outside diameter at the bevel and bored to match, and heat treated to the same level.
Do you make caps and crosses?
Yes, in AISI 4130 to the same dimensional standards and heat treatments as the elbows, tees and reducers. List them on the same request.
What sizes do you make?
NPS 1 to 8 as standard, and heavy-wall sections ordered by outside and inside diameter, such as 5.5 in OD by 3 in ID. Ask for other sizes.