Tesco Steel & Engineering manufactures Hastelloy C276 flanges (UNS N10276 / W.Nr. 2.4819) — the nickel-molybdenum-chromium superalloy with ~57% Ni, ~16% Mo, ~16% Cr and ~3–4% tungsten. C276 offers outstanding resistance to pitting, crevice corrosion, chloride stress-corrosion cracking and to both oxidizing and reducing media — wet chlorine, hypochlorite, ferric/cupric chlorides and hot contaminated acids. Available in weld neck, slip-on, blind, socket-weld, threaded, lap-joint, spectacle and orifice types to ASTM B564 / ASME B16.5. Class 150 to 2500, NPS 1/2″ to 24″, PN6 to PN400. ISO 9001:2015 certified. Made in India.
Hastelloy C276 (UNS N10276) Flanges
Hastelloy C276 Threaded Flange (Polished)
Tesco Steel & Engineering manufactures C276 flanges in all types from weld neck to orifice, Class 150 to 2500 — supplied with EN 10204 3.1 / 3.2 certification, PMI and third-party inspection on request. Explore the wider Hastelloy flange range, the closely-related Hastelloy C22 flanges, and the flange dimension charts.
| Hastelloy C276 flanges are available in the following specifications: | |
|---|---|
| Material Grade | Hastelloy C276 / UNS N10276 / W.Nr. 2.4819 (NiMo16Cr15W) |
| Alloy Type | Nickel-molybdenum-chromium superalloy (Ni-Mo-Cr) |
| Size | 1/2″ NB to 24″ NB (DN 15 to DN 600); larger to ASME B16.47 |
| Class / Rating | 150#, 300#, 600#, 900#, 1500#, 2500# · 3000#, 6000#, 9000# (socket-weld / threaded) |
| Pressure Ratings | PN 6 – PN 400 (PN6, 10, 16, 25, 40, 64, 100, 160, 250, 320, 400) |
| Material Standards | ASTM B564, ASME SB564, AMS 5750; EN designation 2.4819 |
| Dimensional Standards | ASME B16.5, ASME B16.47 (Series A & B), MSS SP-44, DIN EN 1092-1 |
| Flange Types | Weld Neck (WNRF), Slip-On (SORF), Blind, Socket Weld (SWRF), Lap Joint, Threaded / Screwed, Spectacle Blind, Long Weld Neck, Orifice, Plate |
| Flange Faces | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Tongue & Groove (T&G) |
| Weld Filler | ERNiCrMo-4 / ENiCrMo-4 (AWS A5.14 / A5.11) |
| Testing | PMI, hydrostatic, UT, MT/PT per spec; EN 10204 3.1 / 3.2 |
The high molybdenum and tungsten give C276 its outstanding resistance to localized corrosion in reducing and chloride-bearing media, while the chromium provides resistance to oxidizing conditions. The very low carbon (0.01% max) prevents harmful carbide precipitation in welds.
| Element | Hastelloy C276 (UNS N10276) |
|---|---|
| Nickel (Ni) | Balance (~57%) |
| Molybdenum (Mo) | 15.0 – 17.0% |
| Chromium (Cr) | 14.5 – 16.5% |
| Tungsten (W) | 3.0 – 4.5% |
| Iron (Fe) | 4.0 – 7.0% |
| Cobalt (Co) | 2.5% max |
| Manganese (Mn) | 1.0% max |
| Carbon (C) | 0.01% max |
| Silicon (Si) | 0.08% max |
| Vanadium (V) | 0.35% max |
| Mechanical Property (solution annealed, typical) | Hastelloy C276 |
|---|---|
| Tensile Strength | 690 – 790 MPa (100–115 ksi) |
| Yield Strength 0.2% | 283 – 355 MPa (41–51 ksi) |
| Elongation | 40 – 60% |
| Hardness | ≤ 100 HRB (typ. ~90 HRB) |
| Density | 8.89 g/cm³ |
| Melting Range | 1325 – 1370 °C |
| Standard | Hastelloy C276 Designation |
|---|---|
| UNS (USA) | N10276 |
| Werkstoff (Germany) | 2.4819 |
| EN designation | NiMo16Cr15W |
| ASTM / ASME | B564 / SB564 (forgings); B574, B575, B619, B622 (other forms) |
| AMS | 5750 |
| Common name | Hastelloy C-276, Alloy C276 |
C276 Weld Neck Flange (WNRF)
C276 Slip-On Flange (SORF)
C276 Blind Flange
| Flange Type | Description & C276-Specific Use |
|---|---|
| Weld Neck (WNRF) | Tapered hub butt-welded to pipe for high-integrity, high-pressure corrosive service; weld with ERNiCrMo-4 filler, no PWHT. |
| Slip-On (SORF) | Fillet-welded over the pipe; common in chemical and FGD piping at moderate pressure. |
| Blind | Seals pipe ends and vessel nozzles in scrubbers, reactors and acid systems. |
| Socket Weld (SWRF) | Small-bore (1/2″–2″) instrument and branch connections in corrosive service. |
| Lap Joint (LJRF) | Used with a C276 stub end where frequent dismantling is required; economizes on alloy in the backing ring. |
| Threaded (TRFF) | Internal NPT/BSP threads for non-welded low-pressure connections. |
| Spectacle Blind / Long Weld Neck | Isolation spades and nozzle/long-neck flanges in C276 for chemical and pollution-control duty. |
| Property | C276 (N10276) | C22 (N06022) | C2000 (N06200) |
|---|---|---|---|
| Molybdenum | ~16% | ~13% | ~16% |
| Chromium | ~16% | ~22% | ~23% |
| Tungsten | ~3-4% | ~3% | — |
| Copper | — | — | ~1.6% |
| Best in reducing media | Excellent | Very good | Excellent |
| Best in oxidizing media | Good | Excellent | Excellent |
| Typical role | General-purpose Ni-Mo-Cr workhorse | Oxidizing / mixed acids | Both oxidizing & reducing acids |
Withstands both oxidizing and reducing media — one of the few alloys equally at home in mixed and contaminated acids.
High Mo + W give outstanding resistance to localized attack and chloride stress-corrosion cracking.
Very low carbon and silicon resist HAZ sensitization — usable as-welded without PWHT in most applications.
Excellent toughness from cryogenic up to ~1040°C oxidation limit, with high strength and ductility.
| Industry | Typical Application |
|---|---|
| Flue-Gas Desulphurization (FGD) | Scrubber, ducting and stack-liner flanged connections in wet/acidic chloride service |
| Chemical & Petrochemical | Reactor, column and piping flanges in sulphuric, hydrochloric and mixed acids |
| Pharmaceutical & Fine Chemicals | Corrosion-critical process and high-purity flanged joints |
| Pulp & Paper | Bleaching plant (chlorine dioxide) piping and equipment flanges |
| Oil & Gas / Sour Service | Acid-gas, sour and chloride-bearing well-stream flanged connections |
| Pollution Control & Waste | Scrubbers, pickling lines and waste-treatment flanges |
Made from certified C276 with PMI verification of Mo, Cr and W — full chemistry confirmed on the MTC.
Manufactured to ASTM B564 / ASME B16.5 in the solution-annealed condition for full corrosion resistance.
WNRF, SORF, blind, socket-weld, threaded, lap-joint, spectacle, LWN, orifice and plate — in RF, FF, RTJ and T&G.
EN 10204 3.1 / 3.2 MTC, heat/lot traceability, hydrostatic and third-party inspection on request.
C276 flange prices reflect the high nickel, molybdenum and tungsten content plus forging and machining — it is a premium superalloy for the most corrosive service. Tesco Steel & Engineering offers competitive ex-works pricing from Mumbai with full export documentation and material traceability. Click Ask for Quote or message us on WhatsApp at +91 92233 66922 with flange type, size (NB), pressure class, quantity and documentation requirements.
Q1. What is a Hastelloy C276 flange?
A Hastelloy C276 flange is a pipe flange made from the nickel-molybdenum-chromium superalloy UNS N10276 (W.Nr. 2.4819) — about 57% nickel with ~16% molybdenum, ~16% chromium and ~3–4% tungsten. C276 is one of the most universally corrosion-resistant alloys available, resisting pitting, crevice corrosion, chloride stress-corrosion cracking and both oxidizing and reducing chemicals. Flanges are forged to ASTM B564 and machined to ASME B16.5 / B16.47 dimensions in all standard types and classes.
Q2. What is the chemical composition of Hastelloy C276?
Hastelloy C276 (UNS N10276) nominal composition: nickel balance (~57%), molybdenum 15–17%, chromium 14.5–16.5%, tungsten 3–4.5%, iron 4–7%, cobalt 2.5% max, with very low carbon (0.01% max) and silicon (0.08% max). The low carbon and silicon make it resistant to grain-boundary precipitation in the heat-affected zone, so it can be used as-welded in most services.
Q3. What standards apply to Hastelloy C276 flanges?
Hastelloy C276 flanges are forged to ASTM B564 (UNS N10276) and machined to ASME B16.5 (1/2 inch to 24 inch) or ASME B16.47 / MSS SP-44 for larger sizes, with EN 1092-1 for PN-rated flanges. The European designation is W.Nr. 2.4819 / NiMo16Cr15W. Material is supplied with EN 10204 3.1 / 3.2 certification.
Q4. What is the difference between Hastelloy C276 and C22?
Both are Ni-Mo-Cr alloys with excellent corrosion resistance. C276 has higher molybdenum and tungsten, giving superior resistance in reducing environments and to localized (pitting/crevice) attack in hot chloride solutions. C22 (UNS N06022) has higher chromium, giving better resistance in strongly oxidizing media and to a wider range of mixed acids. C276 is the long-established general-purpose grade; C22 is often chosen for highly oxidizing or fluctuating oxidizing/reducing conditions.
Q5. What temperature can Hastelloy C276 flanges handle?
Hastelloy C276 retains good strength and corrosion resistance from cryogenic temperatures up to about 1040 degrees C (1900 degrees F) for oxidation resistance, though for corrosion service it is most often used up to around 400–650 degrees C. It also has excellent low-temperature toughness, making it suitable for cryogenic flanged connections.
Q6. Can Hastelloy C276 flanges be welded?
Yes. Hastelloy C276 has excellent weldability by GTAW (TIG), GMAW and SMAW using matching ERNiCrMo-4 / ENiCrMo-4 filler. Because of its low carbon and silicon it generally needs no post-weld heat treatment and can be used in the as-welded condition. Heat input should be controlled and interpass temperature kept low to preserve corrosion resistance.
Q7. What media is Hastelloy C276 resistant to?
Hastelloy C276 resists wet chlorine, hypochlorite and chlorine dioxide, ferric and cupric chlorides, hot contaminated mineral acids (sulphuric, hydrochloric, phosphoric), acetic and formic acid, seawater and brine, and many mixed/contaminated process streams. It is one of the few alloys that withstands both oxidizing and reducing conditions, which is why it is a default choice for flue-gas desulphurization, chemical processing and pollution-control equipment.
Q8. What are the mechanical properties of Hastelloy C276?
Typical Hastelloy C276 properties in the solution-annealed condition: tensile strength about 690–790 MPa (100–115 ksi), yield strength about 283–355 MPa (41–51 ksi), elongation about 40–60%, density 8.89 g/cm³. It combines high strength with excellent ductility and toughness.
Q9. What industries use Hastelloy C276 flanges?
Hastelloy C276 flanges are used in flue-gas desulphurization (FGD) scrubbers, chemical and petrochemical processing, pharmaceutical and fine-chemical plants, pulp and paper bleaching, pollution control, oil & gas sour-service and acid-gas systems, and pickling/waste-treatment plants — anywhere aggressive, mixed or chloride-bearing media attack stainless steel.
Q10. Are Hastelloy C276 flanges supplied with material test certificates?
Yes. Every Hastelloy C276 flange is supplied with EN 10204 3.1 (or 3.2) mill test certificates confirming chemistry, mechanical properties and heat/lot traceability, with PMI, hydrostatic testing and third-party inspection on request. Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer and exporter from Mumbai, India.