Carbon Steel Swage Nipple — Factory Direct Supplier | Huaxia-Steel
Carbon steel swage nipples are short-length transition fittings used to connect pipes of different diameters or end types in a compact space. Unlike concentric or eccentric reducers, which require two butt welds and significant straight-run length, a swage nipple provides the diameter transition in a single forged piece with one weld at the large end and one at the small end. This makes swage nipples ideal for instrument connections, sample points, vent lines and tight piping layouts where footprint is limited.
Huaxia-Steel manufactures carbon steel swage nipples to MSS SP-95 in both concentric and eccentric geometries, with end preparations including plain bevel, threaded NPT/BSPT and combination bevel-thread. Materials include ASTM A105, A350 LF2 and A234 WPB, with pressure ratings matching ASME B16.11 Class 2000–6000 and ASME B16.9 Schedule 10–XXS.
Product Overview
Swage nipples are distinguished from standard pipe nipples by their tapered body. The large end matches the run pipe diameter; the small end matches the branch or instrument line diameter. The taper angle is typically 7°–10° included angle for concentric swages and 10°–15° for eccentric swages, ensuring smooth flow transition without cavitation or turbulence.
Huaxia-Steel produces swage nipples by closed-die forging on 1,000-tonne upsetter presses, followed by CNC machining of end threads and bevels. Forged swage nipples offer superior grain-flow alignment and fatigue resistance compared with machined-bar or pipe-reduced alternatives. All swages are normalised or stress-relieved after forging to guarantee uniform mechanical properties.
Specifications and Dimensions
| Parameter | Specification |
|---|---|
| Standard | MSS SP-95, ASME B16.11, ASME B16.9 |
| Type | Concentric, eccentric |
| Size range (large end) | 1/4" – 12" NPS |
| Size range (small end) | 1/8" – 8" NPS |
| Schedule / wall | SCH 40, 80, 160, XXS, 2000, 3000, 6000 |
| End preparation | Plain bevel, NPT thread, BSPT thread, combination bevel-thread |
| Length | Standard MSS SP-95 length or custom per drawing |
| Surface finish | Black, pickled, oiled, hot-dip galvanized |
Dimensional tolerances follow MSS SP-95 Table 1 and Table 2. Large-end OD tolerance is ±0.4 mm for sizes up to 2" and ±1 % for larger sizes. Small-end OD tolerance is ±0.3 mm for threaded ends and ±0.4 mm for bevelled ends. Overall length tolerance is ±1.5 mm for lengths up to 150 mm and ±3 mm for longer lengths.
Material Grades and Selection Guide
| Grade | Standard | Pressure Class | Application |
|---|---|---|---|
| ASTM A105 | MSS SP-95 | 2000 / 3000 / 6000 | General oil & gas, water, steam |
| ASTM A105N | MSS SP-95 | 2000 / 3000 / 6000 | Normalised for low-temp toughness |
| A350 LF2 | MSS SP-95 | 2000 / 3000 / 6000 | Cryogenic and Arctic service |
| A234 WPB | ASME B16.9 | SCH 40 / 80 / 160 / XXS | Butt-weld pipeline transitions |
| A234 WPC | ASME B16.9 | SCH 40 / 80 / 160 / XXS | High-strength pipeline transitions |
For threaded swage nipples in high-vibration service (compressor stations, pump discharge lines), specify ASTM A105N with rolled threads rather than cut threads. Rolled threads work-harden the thread root, increasing fatigue life by 200–300 % compared with machined threads. Huaxia-Steel provides rolled-thread swage nipples with thread-profile verification per ASME B1.20.1.
Manufacturing Process and Quality Control
- Forging: 1,000-tonne upsetter press with induction heating to 1,150°C; 3:1 minimum forging ratio
- Heat treatment: Normalising at 880°C±15°C or stress relieving at 620°C for 1 hour per 25 mm
- Machining: CNC turning of tapers; CNC threading with form tooling for NPT/BSPT
- Bevelling: 37.5° V-bevel with 1.6 mm land per ASME B16.25 on plain ends
- NDE: 100 % MT or PT on threaded ends; 10 % random UT on forged body
- Dimensional inspection: CMM on large-end OD, small-end OD, taper angle and overall length
- Thread inspection: Thread plug and ring gauges per ASME B1.20.1; thread-profile projector for random samples
- Hardness test: 10 % sampling, HRC or HB on body and ends
- PMI: XRF alloy verification on every heat
Applications
- Instrument take-off connections on process piping
- Thermowell and pressure-tap installations
- Sample-point and drain connections in refineries
- Small-bore vent and relief lines from main headers
- Pump suction and discharge size transitions
- Compressor station piping with reduced-diameter instrument loops
- Fire protection system branch connections to sprinkler heads
- Utility air and nitrogen distribution drops
Packaging and Shipping
Swage nipples are individually wrapped in VCI film and packed in strong corrugated cartons for sizes up to 2", or in wooden crates for larger sizes. Threaded ends are protected with heavy-duty plastic caps. Each carton or crate contains a packing list showing size, schedule, grade, heat number, quantity and net/gross weight. For export shipments, pallets are fumigated and marked with IPPC compliance stamps.
Standard lead time is 2–3 weeks for A105 threaded swage nipples in common size combinations. A350 LF2 and special taper angles require 3–4 weeks. Large-quantity orders benefit from forging-die amortisation and receive tiered pricing discounts.
Request a Quotation
Contact Huaxia-Steel for a detailed quotation within 24 hours. Please provide:
- Type (concentric or eccentric)
- Large-end size × small-end size (NPS) and schedule
- Material grade (A105, A350 LF2, A234 WPB, etc.)
- End preparation (bevel, NPT, BSPT, combination)
- Quantity and surface finish
- Delivery term (FOB, CIF, DAP) and destination
- Special requirements (NACE, rolled threads, galvanizing, third-party inspection)
