Companies looking for a Hastelloy C276 Flanges Manufacturer in India are often trying to solve a specific corrosion or piping problem, not just source a metal ring. The right enquiry identifies Alloy C276 / UNS N10276, the flange standard, size, facing, bore, pressure class and service conditions. Here is a useful way to compare technical quotations and discuss the scope with SankalPalloys.
What is a Hastelloy C276 flange, and when is it specified?
A C276 flange connects pipes, valves or equipment using a nickel-based corrosion-resistant alloy. It is considered for aggressive chemical services where the engineer has selected UNS N10276. The flange must still match its mating connection, gasket, fasteners and design code.
Is Hastelloy C276 the same as Alloy C276?
Yes. Hastelloy C276 is a trade-name reference to Alloy C276, designated UNS N10276 (also known as W.Nr. 2.4819). It is a nickel-molybdenum-chromium alloy with tungsten and low carbon and silicon. Those constituents help the alloy resist numerous corrosive environments; they do not make it immune to every chemical.
Sticky Q&A — What should I check first? Confirm the grade and service environment, then verify the flange standard, size, class and facing. A chemically correct forging with the wrong bolt pattern still cannot be installed.
Hastelloy C276 chemical composition and grade verification
The following are nominal composition figures from Haynes International, expressed by weight, not an acceptance table for a particular heat. Review the specified material standard and material test certificate (MTC) for actual compliance.
| Element | Nominal content / published maximum |
|---|---|
| Nickel | Balance (about 57% nominal) |
| Chromium | About 16% nominal |
| Molybdenum | About 16% nominal |
| Iron | About 5% nominal |
| Tungsten | About 4% nominal |
| Cobalt | 2.5% maximum |
| Carbon | 0.01% maximum |
| Silicon | 0.08% maximum |
Buyer tip: Write UNS N10276 on the purchase order and require grade and heat-number traceability as agreed. Do not substitute C22 (UNS N06022), Alloy 625 (UNS N06625) or another nickel alloy just because a supplier describes it as “equivalent.”
Hastelloy C276 flange types and how buyers choose them
The flange connection style is a design decision. Availability, forging route, bore and machining details need confirmation against the actual drawing and order quantity.
| Flange type | Typical connection | Detail to confirm |
|---|---|---|
| Weld neck | Butt-welded piping connection | Bore, pipe schedule and weld preparation |
| Slip-on | Fillet-welded connection where permitted | Clearance and welding design |
| Blind | Closes a pipe or nozzle opening | Thickness and design conditions |
| Socket weld | Specified small-bore connections | Socket dimensions and installation gap |
| Threaded | Approved threaded connection | Thread form and service restrictions |
| Lap joint | Backing flange used with a stub end | Stub-end material and geometry |
Raised face, flat face or ring-type joint?
RF is raised face, FF is flat face, and RTJ is ring-type joint. Match the existing joint and gasket specification. A mismatch can create a sealing problem even when the nominal size and pressure class appear correct.
ASME flange classes and C276 piping design checks
ASME B16.5 defines covered flange dimensions and pressure-temperature rating rules for standard flange sizes and classes. Common designations include Class 150, 300, 600, 900, 1500 and 2500; Class 400 is also included. The permitted size range and whether a suitable material group/rating applies must be checked in the governing edition.
| RFQ field | Why it matters |
|---|---|
| Pressure class | Not a standalone operating-pressure figure; rating depends on material and temperature |
| Nominal size (NPS / DN) | Controls flange geometry and available class combinations |
| Bore / pipe schedule | Critical for weld-neck or other bored connections |
| Facing and gasket | Must match the mating flange and sealing design |
Sticky Q&A — Is Class 300 rated for 300 psi? No. “Class 300” is a flange designation, not a fixed 300 psi service limit. Verify the applicable material rating tables, design temperature, bolting and whole-joint design with your engineer.
Material standards, inspection and documentation for C276 flanges
Which specifications belong in a Hastelloy C276 RFQ?
- UNS N10276: The material grade designation for Alloy C276.
- ASTM B564: Covers nickel-alloy forgings, including UNS N10276, subject to the applicable edition and order requirements.
- ASME SB-564: Relevant when the project code calls for the ASME-adopted forging specification.
- ASME B16.5: Applicable flange dimensional and rating requirements within its scope; verify material applicability.
- Approved drawing / project specification: Controls special geometry, machining, tolerances and supplementary inspection.
What inspection paperwork should be requested?
Depending on the contract, request a material test certificate (MTC), heat-number traceability, dimensional inspection report and any specified PMI (positive material identification), NDT or third-party inspection. Agree the certificate format and required witnessing before manufacture or procurement, rather than assuming every document is included.
Practical point: If the mating flange is already on site, share its standard, face and bolt pattern. A drawing or photograph alone may omit dimensions that matter.
Where are Hastelloy C276 flanges used?
Alloy C276 is considered in chemical-processing equipment, acid-handling lines, certain pollution-control and flue-gas treatment systems, and other specified corrosion-resistant piping. Its resistance to pitting, crevice corrosion and chloride-related stress corrosion cracking can be valuable, but performance still depends on temperature, concentration, contaminants and operating history.
When should engineers reassess C276?
Do not treat “corrosion resistant” as universal. Strongly oxidizing conditions, complex mixed acids, elevated temperatures or unexpected deposits can change the assessment. The correct choice relies on actual fluid chemistry, corrosion data, weld design and construction-code requirements. Check whether a solid C276 flange or an engineered alternative is specified.
SankalPalloys technical team perspective (proposed wording; verify internally before attributing): “For C276 flanges, we would rather see the service conditions and mating-flange details with the enquiry. Grade and size alone do not tell the whole story.”
How to request a Hastelloy C276 flange quotation in India
For a clearer offer and fewer revisions, send one RFQ containing the following:
- Grade: Hastelloy C276 / Alloy C276 / UNS N10276.
- Flange type, quantity and any approved drawings.
- Nominal size (NPS / DN), bore or pipe schedule.
- Dimensional standard, pressure class and facing (RF, FF or RTJ).
- Material forging specification and required condition.
- Design pressure, temperature and process medium, where relevant.
- MTC, heat traceability, PMI, NDT and inspection scope, if specified.
- Delivery destination, required date, packing and commercial terms.
Four purchasing mistakes worth avoiding
1. Using “C276” without the UNS number and material standard. 2. Leaving out flange facing or weld-neck bore. 3. Assuming an ASTM forging grade automatically defines an ASME pressure rating. 4. Requesting PMI or third-party inspection only after the quotation has been approved.
Sticky Q&A — How do I compare two C276 flange quotes? Compare the same material specification, flange drawing, dimensional tolerance, inspection scope, certificates, quantity, packaging and delivery terms. A lower piece price may exclude important requirements.
For a C276-specific enquiry, contact SankalPalloys with your drawing or bill of materials. Ask for written confirmation of product scope and availability rather than relying on a generic product description.
FAQs: Hastelloy C276 flanges in India
What is the UNS grade for Hastelloy C276 flanges?
Hastelloy C276 (Alloy C276) is UNS N10276, a nickel-molybdenum-chromium alloy. Specify the UNS grade and the applicable material standard in your RFQ.
Is ASTM B564 suitable for C276 forged flanges?
ASTM B564 includes UNS N10276 nickel-alloy forgings. It addresses forging-material requirements; use the relevant dimensional and piping design standards separately.
What flange types can I enquire about?
Typical enquiries include weld neck, slip-on, blind, socket weld, threaded and lap joint configurations. Actual manufacturing or supply feasibility depends on the size, material, standard and drawing.
Does Class 150 or Class 300 tell me the working pressure?
No. The pressure-temperature rating depends on the governing standard, material coverage and design temperature. Have the full flanged joint checked for its intended service.
Is C276 better than stainless steel 316L for acid service?
C276 can outperform 316L in some aggressive acid and chloride environments, but neither is universally suitable. Compare corrosion data at the actual concentration, temperature and contamination level.
Which certificates should I request with C276 flanges?
Specify an MTC and heat traceability as needed, plus agreed dimensional reports, PMI, NDT or third-party inspection. Confirm exact requirements in the purchase order.
Can C276 flanges be substituted with Alloy C22 or Alloy 625?
Not without engineering approval. UNS N10276, N06022 and N06625 have different compositions and service characteristics, so substitution requires a documented design review.
What information helps obtain a usable quotation in India?
Send UNS N10276, flange type, size, bore, standard, class, facing, quantity, inspection needs, delivery location and requested date. Include a drawing for special configurations.
Discuss your Hastelloy C276 flange requirements with SankalPalloys
Share your UNS N10276 flange drawing, class, facing, bore, material standard, quantity and inspection expectations. Contact SankalPalloys to clarify the technical scope, quotation details and delivery requirements before ordering.
Technical references
For material identification and purchasing checks, verify the current edition and project requirements using these original references:
- Haynes International — HASTELLOY C-276 technical alloy data
- ASME B16.5 — Pipe Flanges and Flanged Fittings
- ASTM B564 — Standard Specification for Nickel Alloy Forgings
This article provides general purchasing guidance, not engineering approval or confirmation of stock, manufacturing capability or availability for a specific order. Verify engineering suitability, applicable editions, documentation and commercial terms before ordering.