Description
Nickel-chromium-molybdenum alloy fitting
Hastelloy C276 Butt Weld Pipe Cap
A highly corrosion-resistant nickel-alloy closure for chemical processing, pollution control and mixed-acid piping.
What is a Hastelloy C276 butt weld pipe cap?
A C276 butt weld pipe cap is a factory-made wrought nickel-alloy fitting used to close the end of a pressure piping run. ASTM B366/B366M covers factory-made wrought nickel and nickel-alloy fittings, while ASME B16.9 or MSS SP-43 supplies the ordered dimensional basis.
UNS N10276 is a nickel-chromium-molybdenum alloy with tungsten and very low carbon and silicon. It is valued for resistance across a broad range of reducing and oxidizing chemical environments and for maintaining corrosion resistance in welded fabrication. Suitability still depends on chemical composition, concentration, temperature and contaminants.
C276 butt weld pipe cap specifications
| Product | Nickel-alloy butt weld pipe cap / end cap |
|---|---|
| ASTM material | ASTM B366/B366M, ordered C276 grade and class |
| Material designations | UNS N10276; EN 2.4819 / NiMo16Cr15W |
| Dimensional standards | ASME B16.9 for WP fitting classes; MSS SP-43 for CR class when ordered |
| Nominal size | NPS 1/2–48 / DN15–DN1200, subject to alloy availability and forming route |
| Wall thickness | Sch 5S–Sch 160, XXS and project-specific wall, subject to review |
| Construction / class | Seamless or welded; ASTM B366 WP/CR class designation stated on the order |
| End preparation | Butt-weld bevel end (BE) matched to connecting pipe and WPS |
| Condition | Solution heat treated and descaled/cleaned to the ordered specification |
| Documentation | EN 10204 3.1 MTC, PMI, dimensions and class-related NDE records as ordered |
ASME B16.9 covers factory-made wrought butt-welding fitting dimensions, tolerances, ratings, testing and marking. Material acceptance follows the ordered ASTM specification. Availability at NPS 1/2–48 and heavy walls is subject to alloy, size, quantity and manufacturing route.
ASME B16.9 and MSS SP-43 supply options
ASME B16.9
ASTM B366 WP fitting classes use ASME B16.9 dimensional and rating requirements. State seamless/welded class and the required NDE extent.
MSS SP-43
ASTM B366 CR-class fittings use MSS SP-43 dimensions where specified. Confirm the piping design permits this lower-pressure corrosion-resistant fitting basis.
Hastelloy C276 vs Inconel 625 pipe cap
| Selection point | C276 / N10276 | Alloy 625 / N06625 |
|---|---|---|
| Alloy focus | High molybdenum with tungsten for broad chemical resistance | Ni-Cr-Mo-Nb alloy combining strength and corrosion resistance |
| Typical advantage | Mixed acids, reducing media and pollution-control chemicals | Seawater, offshore, fatigue and elevated-temperature strength |
| Fabrication | Excellent welded corrosion behavior with qualified procedure | Strong weldability; procedure must control heat input and cleanliness |
| Selection rule | Choose from actual chemical service data | Choose when strength plus marine/process resistance is needed |
Typical applications
| Industry | Typical service | Selection reason |
|---|---|---|
| Chemical processing | Reactors, transfer lines and mixed-acid systems | Broad resistance in many aggressive chemicals |
| Pollution control | FGD, wet scrubbers and waste-treatment piping | Resistance to acidic chlorides and variable contaminants |
| Pharmaceutical / fine chemical | High-purity aggressive reagent service | Corrosion resistance plus welded-system integrity |
| Pulp and paper | Bleaching and chlorine-related process systems | Useful resistance in selected wet chlorine and chloride media |
Application examples are not a design approval. The piping materials engineer must confirm corrosion compatibility, temperature, pressure, weld procedure and applicable code requirements.
Manufacturing, inspection and EN 10204 documentation
C276 caps require controlled raw material, forming, solution heat treatment and clean fabrication. ASTM B366 class determines construction and NDE expectations, so the complete class designation must be agreed before manufacture.
Material certificate and heat-number traceability matched to the ordered grade.
PMI verifies key alloying elements when specified in the inspection plan.
Outside diameter, overall length, wall thickness, ovality and BE geometry checked.
PT, UT, RT, surface condition or third-party witnessing arranged when ordered.
RFQ checklist
- ASTM grade and UNS number
- ASME B16.9 or MSS SP-43 edition
- NPS or DN size
- Schedule or exact wall thickness
- Seamless or welded construction/class
- BE bevel detail and matching pipe
- Quantity and delivery destination
- EN 10204 3.1, PMI, dimensional and NDE requirements
Frequently asked questions
Which ASTM standard covers C276 pipe caps?
ASTM B366/B366M covers factory-made wrought nickel and nickel-alloy fittings, including caps. The order must identify the C276 grade, WP or CR class and dimensional standard.
What are the UNS and EN designations?
Hastelloy C276 is UNS N10276 and is commonly cross-referenced as EN 2.4819 / NiMo16Cr15W.
What is the difference between WP and CR classes?
WP classes relate to ASME B16.9, B16.11 or B16.28 requirements and specify construction/NDE class. CR classes relate to MSS SP-43 corrosion-resistant fittings.
Can C276 caps be supplied seamless or welded?
Yes, depending on size, wall and ordered ASTM B366 class. The class designation and NDE extent should be stated rather than using only the word seamless or welded.
Why is PMI important for C276?
C276 resembles other nickel alloys visually. PMI verifies key alloying elements and supports traceability before a high-value component enters fabrication.
Request a C276 butt weld cap quotation
Provide the ASTM B366 grade/class, size, wall, bevel, quantity and inspection plan for technical review.
