Butt Weld Fittings
NUMET ALLOYS manufactures a comprehensive range of industrial butt weld fittings engineered for seamless fluid handling. Forged with absolute precision, our components are designed to accommodate extreme pressures, volatile temperatures, and highly corrosive media without compromising structural integrity.
Technical Specifications
Dimensional Standards & Tolerances
Every fitting we supply is made to the dimensional standard for its type, with centre-to-end dimensions and tolerances taken from ASME B16.9 (and ASME B16.28 for short radius elbows, MSS SP-43 for short pattern stub ends). Full size tables are published on each product page.
Standard and Size Range by Fitting Type
Reference| Fitting Type | Dimensional Standard | Size RangeNPS | Dimension Table |
|---|---|---|---|
| Elbows 90° & 45° (long radius) | ASME B16.9 | 1/2 – 48 | Elbow dimensions |
| Elbows 90° (short radius) | ASME B16.28 | 1 – 24 | Elbow dimensions |
| 180° returns (long & short radius) | ASME B16.9 / B16.28 | 1/2 – 24 | Elbow dimensions |
| Tees — straight & reducing outlet | ASME B16.9 | 1/2 – 48 | Tee dimensions |
| Crosses — straight & reducing outlet | ASME B16.9 | 1/2 – 48 | Cross dimensions |
| Reducers — concentric & eccentric | ASME B16.9 | 3/4 – 48 | Reducer dimensions |
| Caps | ASME B16.9 | 1/2 – 48 | Cap dimensions |
| Stub ends — long pattern | ASME B16.9 | 1/2 – 24 | Stub end dimensions |
| Stub ends — short pattern | MSS SP-43 | 1/2 – 24 | Stub end dimensions |
ASME B16.9 Dimensional Tolerances
ASME B16.9| SizeNPS | Outside Dia. at Bevelmm | Inside Dia. at Endmm | Centre-to-Endmm | 180° Centre-to-Centremm | 180° Back-to-Facemm | Alignment of Endsmm |
|---|---|---|---|---|---|---|
| 1/2 – 2-1/2 | +1.6 / −0.8 | 0.8 | 2 | 6 | 6 | 0.8 |
| 3 – 3-1/2 | ±1.6 | 1.6 | 2 | 6 | 6 | 0.8 |
| 4 | ±1.6 | 1.6 | 2 | 6 | 6 | 0.8 |
| 5 – 8 | +2.4 / −1.6 | 1.6 | 2 | 6 | 6 | 0.8 |
| 10 – 18 | +4.0 / −3.2 | 3.2 | 2 | 10 | 6 | 1.6 |
| 20 – 24 | +6.4 / −4.8 | 4.8 | 2 | 10 | 6 | 1.6 |
| 26 – 30 | +6.4 / −4.8 | 6.4 / 4.8 | 3 | — | — | 4.8 |
| 32 – 48 | +6.4 / −4.8 | 6.4 / 4.8 | 5 | — | — | 4.8 |
Tolerances are ± unless shown otherwise. Wall thickness at any point must be at least 87.5% of the specified nominal wall. Out-of-round is the sum of the plus and minus tolerances. Inside diameter and nominal wall at the ends are specified by the purchaser.
Dimensions are nominal values from the referenced standard and are shown for reference only; tolerances apply as specified in the standard. Sizes above 24" NB and non-standard combinations are manufactured to order. For certified drawings against your line list, contact our technical team.
Core Advantages
Dimensional Accuracy
Precision-machined tolerances ensure perfect alignment and flawless welding during installation.
High Tensile Strength
Forged construction prevents structural deformation under extreme hydrostatic pressure.
Corrosion Resistance
Premium alloy grades provide superior longevity in highly acidic and chemical environments.