Inconel 600 flanges are piping connection components made from the nickel-chromium-iron alloy known as Alloy 600 or UNS N06600. They can be considered for equipment exposed to demanding temperatures or certain corrosive media. Selecting the correct flange also requires its manufacturing specification, type, facing, dimensions, pressure-temperature rating, gasket and bolting details.
What is Inconel 600 (UNS N06600)?
Alloy 600 is a solid-solution nickel-chromium-iron material, also identified as W.Nr. 2.4816. Its high nickel content supports resistance to a variety of reducing environments, while chromium contributes to oxidation resistance. Alloy 600 is not precipitation-hardenable; cold working is an important strengthening mechanism.
For a flange, alloy identification alone does not establish whether a piping joint is safe for a given temperature and pressure. Design codes, allowable stresses, assembly details and compatible components must all be checked.
Inconel 600 chemical composition (UNS N06600)
The following composition limits are commonly listed in the alloy producer's technical bulletin. Values are mass percentages, and the applicable material specification and actual certificate govern acceptance.
| Element | Typical specified limit |
|---|---|
| Nickel + cobalt | 72.0% minimum |
| Chromium | 14.0–17.0% |
| Iron | 6.0–10.0% |
| Carbon | 0.15% maximum |
| Manganese | 1.0% maximum |
| Silicon | 0.50% maximum |
| Copper | 0.50% maximum |
| Sulfur | 0.015% maximum |
Types of Inconel 600 flanges
The required geometry depends on whether the flange connects pipe, equipment or a blind termination. Availability in UNS N06600 and the applicable construction specification must be confirmed for each style.
| Flange type | Typical purpose | What to confirm |
|---|---|---|
| Weld neck | Butt-welded connection with tapered hub | Bore, pipe schedule, welding procedure |
| Slip-on | Fits over pipe and is joined with fillet welds | Fit-up, applicable code, weld details |
| Blind | Closes a line or equipment opening | Thickness, design load, access requirements |
| Socket weld | Socket arrangement for specified pipe sizes | Size range, gap and welding requirements |
| Threaded | Mechanical threaded connection when approved | Thread form and process suitability |
| Lap joint / loose flange | Used with a compatible stub end | Stub-end alloy, dimensions and materials |
Flange facing: RF, FF and RTJ
Raised face (RF), flat face (FF) and ring-type joint (RTJ) refer to sealing-face arrangements. The facing, gasket design and bolt load must be compatible with the mating flange, applicable dimensional standard and service conditions.
Inconel 600 flange pressure classes: 150, 300, 600 and beyond
ASME B16.5 includes Class 150, 300, 400, 600, 900 and 1500 for applicable flanges in NPS 1/2 through NPS 24, and Class 2500 for NPS 1/2 through NPS 12. These are classifications in a pressure-temperature rating system, not guaranteed working pressures in psi. For a nickel-alloy flange, check whether the specific material is covered by the relevant standard or requires a project-approved alternative.
| Designation | Selection note |
|---|---|
| Class 150 / 300 | Common class designations; verify allowable pressure at design temperature |
| Class 400 / 600 | Different dimensions and pressure-temperature tables may apply |
| Class 900 / 1500 | Confirm design, material grouping, flange geometry and availability |
| Class 2500 | Within B16.5, limited to specified size range; use only when applicable |
Important: A complete flanged joint is also constrained by bolts, gaskets, flange facing, thermal cycling, installation and the governing piping code. Never select an operating pressure from the class number alone.
Standards and material test certificates
- UNS N06600: Alloy designation identifying the chemistry family.
- ASTM B564/B564M or ASME SB-564: Referenced for appropriate nickel-alloy forgings; check the edition, material grade and exact product scope.
- ASME B16.5: Specifies dimensional and pressure-temperature requirements for covered pipe flanges and flanged fittings.
- ASME B16.47: May be specified for selected larger steel flanges; verify coverage, approved material and project requirements instead of assuming interchangeability.
- Customer drawing / piping code: Must specify the actual dimensions, facing, inspection and applicable code rules.
For traceability, request a material test certificate documenting grade, heat number, chemistry and applicable testing. Additional requirements such as PMI, NDT or third-party inspection should be explicitly stated when needed.
Industrial applications and corrosion considerations
Inconel 600 may be selected for chemical processing, furnace and high-temperature equipment, and other services where its verified corrosion and heat-resistance properties are appropriate. Its use in a flange assembly still depends on design temperature, internal pressure, fluid chemistry and approved construction rules.
Where a closer corrosion assessment is essential
Alloy 600 is not universally corrosion-proof. Oxidizing solutions, sulfur-bearing environments, contamination, thermal cycles and process chemistry can change material performance. Consult suitable corrosion data and a qualified materials engineer for the actual environment. Do not substitute Alloy 600 for Alloy 625, 800-series or a stainless grade solely on the basis of broad marketing descriptions.
How to specify Inconel 600 flanges for a quotation
- Material: Inconel 600 / Alloy 600 / UNS N06600.
- Flange type: weld neck, blind, slip-on, socket weld or specified alternative.
- Nominal size (NPS or DN), pipe schedule/bore and quantity.
- Pressure class and governing dimensional standard, where applicable.
- Facing: RF, FF, RTJ or project drawing.
- Material / forging standard and required condition.
- Service conditions: design pressure, temperature and fluid environment.
- Material certificates, traceability, inspections and delivery location.
To discuss a product enquiry, visit the Inconel 600 flanges product page. You can also contact Sankalp Alloys Overseas with the drawing or technical specifications to check suitable supply options.
Frequently asked questions about Inconel 600 flanges
What is an Inconel 600 flange?
It is a piping or equipment connection component made from Alloy 600, a nickel-chromium-iron alloy identified as UNS N06600. Its specification, form and pressure-temperature rating must match the project design.
Is ASTM B564 the flange pressure-rating standard?
No. ASTM B564/B564M concerns certain nickel-alloy forgings; ASME B16.5 and related piping standards cover flange dimensions and applicable pressure-temperature ratings.
What pressure classes are available under ASME B16.5?
The standard includes Class 150, 300, 400, 600, 900 and 1500 for certain sizes, and Class 2500 for a smaller size range. Actual class applicability to Alloy 600 and allowable operating pressure require checking the current standard and project specification.
Are Class 150 and Class 300 the same as 150 psi and 300 psi?
No. A pressure class is a rating designation, not a constant pressure limit in psi. Allowable pressure varies with temperature and approved material grouping.
Can Inconel 600 flanges be used at high temperatures?
Alloy 600 is used in elevated-temperature service, but a particular flange assembly requires verification of allowable stresses, gasket and bolting limits, temperature, corrosion and governing code.
What information should I include in a quotation enquiry?
Specify UNS N06600, flange type and facing, size/NPS, class, governing standard, bore or schedule, material condition, quantity, inspection and certificate requirements.
Need Inconel 600 flanges for your project?
Share the UNS grade, flange type, standard, size, class, facing, service temperature, required certificates and quantity via our contact page for a technical enquiry.
Technical references
For specification and design verification, consult the applicable edition of these original references:
- Special Metals — INCONEL alloy 600 technical bulletin (PDF)
- ASME B16.5 — Pipe Flanges and Flanged Fittings
This guide is general educational information, not an engineering design approval or confirmation of inventory. Actual material and flange ratings must be verified against the applicable codes and certificate.