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When specifying Alloy 825 fittings, the material name alone is not enough. A technically complete requirement normally needs to identify the alloy, material specification, fitting type, dimensional standard, connection method, size, schedule or wall requirement, and any inspection or documentation requirements applicable to the project.
For Alloy 825, buyers may encounter terminology such as Alloy 825, INCOLOY® Alloy 825, Incoloy 825, UNS N08825, W.Nr. 2.4858, and the commonly used market/search term "Inconel 825." For procurement clarity, the most useful identifiers are the alloy designation together with UNS N08825 and the applicable product specification.
For fittings, the standards most often encountered in an RFQ or purchase order include:
- ASTM B366/B366M — material/product specification for factory-made wrought nickel and nickel-alloy fittings
- ASME B16.9 — dimensional requirements for factory-made wrought butt-welding fittings
- ASME B16.11 — dimensional requirements for forged socket-welding and threaded fittings
- MSS SP-43, SP-95 and SP-97 — additional fitting standards that can appear depending on the fitting type and application
The important point is that ASTM B366, ASME B16.9 and ASME B16.11 do different jobs. They should not be treated as interchangeable specifications.
1. What Is Alloy 825?
Alloy 825 is a nickel-iron-chromium alloy with molybdenum, copper and titanium additions. It is commonly identified as:
- Alloy 825
- INCOLOY® Alloy 825
- UNS N08825
- W.Nr. 2.4858
For an international RFQ, using UNS N08825 alongside the applicable material specification helps reduce ambiguity between commercial names and technical requirements.
The expression "Inconel 825" is also encountered in search queries, catalogues and commercial communication. Buyers should not rely on that market term alone. A purchase specification should identify the material by a recognized designation such as Alloy 825 / UNS N08825 and then state the applicable ASTM/ASME specification.
2. Which Standard Covers Alloy 825 Fittings?
ASTM B366/B366M
ASTM B366/B366M is the primary material/product specification to understand when discussing factory-made wrought nickel and nickel-alloy fittings.
The current ASTM listing identifies ASTM B366/B366M-25 as the active edition, titled:
Standard Specification for Factory-Made Wrought Nickel and Nickel Alloy Fittings.
The specification covers wrought fittings manufactured from nickel and nickel alloys, including fitting types associated with butt-welding, socket-welding and threaded applications under the applicable dimensional standards.
For Alloy 825, an RFQ may therefore identify the material as:
ASTM B366/B366M, UNS N08825
or, where the applicable code format requires it:
ASME SB-366, UNS N08825
The exact edition and ordering requirements should always be confirmed against the project specification and the purchaser's applicable code edition.
ASTM B366 is not the dimensional standard
This distinction is important.
ASTM B366 establishes requirements associated with the material/product specification and manufacturing of the fitting.
It does not replace the dimensional standard.
For example:
ASTM B366 + ASME B16.9
can describe a wrought butt-welding fitting where B366 establishes the material/product requirements and B16.9 establishes the dimensional requirements.
Likewise:
ASTM B366 + ASME B16.11
may appear where the fitting is within the B16.11 scope.
The RFQ should therefore make the material specification and dimensional standard explicit rather than simply stating "Alloy 825 fittings."
3. ASTM B366 vs ASME B16.9 vs ASME B16.11
A simple way to understand the standards is:
| Standard | What it primarily addresses | Typical relevance |
|---|---|---|
| ASTM B366/B366M | Material/product requirements for factory-made wrought nickel and nickel-alloy fittings | Alloy 825 fitting material specification |
| ASME B16.9 | Dimensions and requirements for factory-made wrought butt-welding fittings | Butt-weld elbows, tees, reducers, caps, etc. |
| ASME B16.11 | Forged socket-welding and threaded fittings | Socket-weld and threaded fittings |
| MSS SP-43 | Certain corrosion-resistant wrought butt-welding fittings | Specific fitting/product configurations |
| MSS SP-95 | Swage nipples and bull plugs | Where applicable |
| MSS SP-97 | Integrally reinforced forged branch outlet fittings | Branch outlet applications |
The key procurement principle is:
Material specification + dimensional standard + fitting configuration
rather than one standard being expected to define everything.
ASME identifies the B16 committee as responsible for standards covering valves, flanges, fittings and gaskets used in pressure services. Its current listings include B16.9-2024 for factory-made wrought butt-welding fittings.
4. Alloy 825 Butt-Welding Fittings — ASME B16.9
For butt-welding fittings, ASME B16.9 is the dimensional standard most commonly encountered.
Typical fitting types include:
- 45° elbows
- 90° elbows
- 180° returns
- Equal tees
- Reducing tees
- Concentric reducers
- Eccentric reducers
- Caps
- Other applicable butt-welding configurations
The fitting may therefore be specified using a combination such as:
Alloy 825 / UNS N08825 ASTM B366/B366M ASME B16.9
The important distinction is that B16.9 describes the dimensional and related requirements of the fitting, while B366 addresses the nickel-alloy fitting material/product requirements.
ASME currently lists B16.9-2024 as the issued edition of Factory-Made Wrought Buttwelding Fittings.
5. Alloy 825 Socket-Welding and Threaded Fittings — ASME B16.11
ASME B16.11 is used for forged socket-welding and threaded fittings.
This is a different fitting category from the factory-made wrought butt-welding fittings covered by B16.9.
Typical B16.11 configurations can include:
- Socket-welding elbows
- Socket-welding tees
- Socket-welding couplings
- Socket-welding unions
- Threaded elbows
- Threaded tees
- Threaded couplings
- Bushings
- Plugs
- Other applicable forged fittings
An RFQ could therefore contain a requirement along the lines of:
Alloy 825 / UNS N08825 Material specification: ASTM B366/B366M or applicable forging/material specification Dimensional standard: ASME B16.11 Connection: Socket-welding
The exact material route matters.
6. Why You May See B366 + B16.11 or B564 + B16.11
This is an important procurement nuance.
ASTM B366 itself covers factory-made wrought nickel and nickel-alloy fittings and includes fittings associated with ASME B16.11. ASTM's scope also identifies WP fittings manufactured to applicable ASME dimensional standards including B16.9 and B16.11.
However, in actual procurement documentation, forged socket-welding or threaded fittings may also be specified using a forging material route, such as:
ASTM B564 + ASME B16.11
depending on the fitting, manufacturing route, purchaser specification and project requirements.
Therefore, an RFQ should not be interpreted solely from the dimensional standard.
The buyer should establish:
- Which material/product specification applies?
- Is the fitting manufactured through a wrought fitting route or forging route?
- Which dimensional standard applies?
- What connection type is required?
- What inspection and documentation requirements apply?
For Alloy 825, this distinction is especially useful when reviewing an RFQ that uses terms such as WPNICMC, CRNICMC, B366, B564, or B16.11.
7. What Do WPNICMC and CRNICMC Mean?
Buyers may encounter WPNICMC and CRNICMC in Alloy 825 fitting specifications.
These are not alternative names for UNS N08825. They are ASTM B366 fitting grade/class designations associated with the nickel-iron-chromium-molybdenum-copper alloy family.
For UNS N08825, the B366 designation encountered in procurement documentation is:
WPNICMC
and the corresponding CR designation is:
CRNICMC
ASTM B366 uses WP and CR prefixes for fitting grades based on the applicable ASME or MSS dimensional/rating standards. The WP and CR classifications are then used with additional class information to identify the applicable fitting construction and examination requirements.
A buyer may therefore see an Alloy 825 requirement written in a form similar to:
ASTM B366/B366M — UNS N08825 — WPNICMC
or:
ASTM B366/B366M — UNS N08825 — CRNICMC
The exact designation required should be confirmed against the applicable edition of the standard and purchase specification.
8. What Are WP and CR Classes?
ASTM B366 uses fitting designations beginning with WP or CR.
The important point is that these designations should not be treated as simple alloy names.
They are associated with the applicable dimensional/rating standard and the fitting's construction and examination requirements.
For WP fittings, ASTM B366 identifies classes that distinguish aspects such as whether the fitting is seamless or welded and the applicable nondestructive examination method or extent.
This is why an RFQ containing something such as:
ASTM B366 WPNICMC-S
should not be reduced to merely:
Alloy 825 fitting
The suffix and class information can carry procurement significance.
Do not remove or simplify a WP/CR designation from an existing purchase specification unless the applicable standard and purchaser requirements have been checked.
9. Alloy 825 Fitting Types
Depending on the applicable dimensional standard and manufacturing route, Alloy 825 fittings can be specified in configurations such as:
Butt-welding fittings
- 45° elbows
- 90° elbows
- Long-radius elbows
- 180° returns
- Equal tees
- Reducing tees
- Concentric reducers
- Eccentric reducers
- Caps
- Lap-joint stub ends where applicable
These are typically associated with ASME B16.9 or another applicable MSS standard.
Socket-welding and threaded fittings
Depending on the application and specification:
- Socket-welding elbows
- Socket-welding tees
- Couplings
- Unions
- Bushings
- Threaded elbows
- Threaded tees
- Threaded couplings
- Plugs
These are associated with ASME B16.11 where applicable.
The exact fitting type should always be stated in the RFQ rather than relying on the generic term "pipe fittings."
10. How Should Alloy 825 Fittings Be Specified on an RFQ?
A useful RFQ should identify the requirements in separate layers.
For example:
Material: Alloy 825 / UNS N08825 Product: Butt-welding elbow Material specification: ASTM B366/B366M Grade/designation: WPNICMC, where applicable Dimensional standard: ASME B16.9 Size: [NPS] Wall/schedule: [required schedule or wall] Angle: [45° / 90° / other] End connection: Butt-welding Quantity: [quantity] Inspection: [project requirement] Documentation: Material Test Certificate / applicable certification requirements Marking: As specified by applicable standard/project Additional requirements: [NDE / PMI / TPI / special testing, if required]
For socket-welding or threaded fittings, the dimensional standard would generally be changed to the applicable ASME B16.11 requirement.
This format makes it much easier for a supplier to identify what is actually being requested.
11. What Should Be Included in the Material Documentation?
For Alloy 825 fittings, buyers may request documentation such as a material test certificate or inspection documentation depending on the purchase order and project specification.
The exact requirements should be stated in the RFQ.
Possible requirements may include:
- Heat/lot identification
- Material specification
- UNS designation
- Chemical analysis
- Mechanical test results
- Heat-treatment information where applicable
- Product dimensions
- Applicable NDE requirements
- PMI where specifically required
- Third-party inspection where specified
- EN 10204 documentation category where required by the purchaser
Not every Alloy 825 fitting order automatically requires every inspection activity.
For example, PMI, radiography, ultrasonic examination, hardness testing or third-party inspection should not be presented as universally mandatory unless the applicable specification, purchase order or project requirement calls for them.
12. Does ASTM B366 Automatically Mean Hydrostatic Testing?
No.
This is an important distinction when comparing supplier descriptions.
ASTM B366 does not mean that every fitting must automatically be described as having undergone a particular hydrostatic test.
Testing requirements depend on the applicable specification, supplementary requirements and purchase order.
ASTM's published scope also provides supplementary requirements where a purchaser wants a greater degree of examination.
Therefore, an RFQ should state additional testing or inspection requirements when they are required by the project.
13. ASTM B366 and ASME SB-366
International RFQs may use both ASTM and ASME terminology.
You may encounter:
ASTM B366
and:
ASME SB-366
These references are related to the material specification used within the applicable ASME code framework.
A supplier should confirm the exact code edition and specification required by the purchase order rather than assuming that ASTM and ASME references can always be substituted without qualification.
For pressure equipment and code-controlled projects, the applicable construction code and edition should take precedence over a generic commercial description.
14. Current Edition References
Standards are periodically revised.
At the time of preparing this guide:
- ASTM B366/B366M-25 is listed by ASTM as the active specification for factory-made wrought nickel and nickel-alloy fittings.
- ASME B16.9-2024 is listed by ASME as the issued edition for factory-made wrought butt-welding fittings.
- ASME B16.11 remains the applicable standard for forged socket-welding and threaded fittings, with the applicable project/code edition to be confirmed before procurement.
Standards should always be checked against the edition specified by the purchaser, project, design code or applicable jurisdiction.
Do not assume that the newest commercially listed edition automatically replaces the edition named in an existing purchase order.
15. Alloy 825 Fittings: Material Specification vs Dimensional Standard
One of the most common mistakes in technical RFQs is treating the material and dimensional requirements as if they were the same thing.
Consider:
ASTM B366 + ASME B16.9
The first part identifies the applicable material/product specification.
The second establishes dimensional requirements for the butt-welding fitting.
Similarly:
Applicable material/forging specification + ASME B16.11
can identify a forged socket-welding or threaded fitting route.
This separation makes the RFQ much more precise.
Think of the specification in layers:
1. Alloy
Alloy 825 / UNS N08825
↓
2. Product/material specification
ASTM B366/B366M or applicable material/forging specification
↓
3. Fitting configuration
Elbow / Tee / Reducer / Cap / Coupling / etc.
↓
4. Dimensional standard
ASME B16.9 / B16.11 / applicable MSS standard
↓
5. Size and wall
NPS / schedule / wall requirement
↓
6. Inspection and documentation
MTC / PMI / NDE / TPI / EN 10204 / project-specific requirements
This is the level of detail a procurement team should aim for.
16. Common Alloy 825 Fitting RFQ Mistakes
Mistake 1: Writing only "Inconel 825 fittings"
The commercial term may be understood by suppliers, but it is not sufficient as a complete technical specification.
Better: Alloy 825 / UNS N08825 + applicable material specification + fitting standard.
Mistake 2: Listing B16.9 without identifying the material specification
B16.9 defines the dimensional requirements for factory-made wrought butt-welding fittings. It does not by itself tell the supplier which nickel alloy material is required.
Better: State the alloy/material specification separately.
Mistake 3: Treating B366 and B16.9 as alternatives
They serve different purposes.
B366: material/product specification.
B16.9: dimensional standard for applicable butt-welding fittings.
Mistake 4: Ignoring the manufacturing route
For certain socket-welding or threaded fittings, the material route may be specified differently depending on the product and project.
Better: Confirm whether the purchase requirement is based on B366 or an applicable forging specification such as B564, together with B16.11 where applicable.
Mistake 5: Removing WP/CR information
If a purchase specification contains WPNICMC or CRNICMC, do not remove the designation simply because "UNS N08825" is already present.
The designation can communicate fitting classification requirements.
Mistake 6: Assuming every fitting requires the same inspection package
PMI, NDE, TPI and additional testing should be specified according to the project and purchase requirements.
17. A Practical Alloy 825 Fitting RFQ Example
A buyer sourcing a 90° butt-welding elbow could structure the requirement as:
Product: Alloy 825 90° butt-welding elbow Material: Alloy 825 / UNS N08825 Material specification: ASTM B366/B366M Grade: WPNICMC, where applicable Dimensional standard: ASME B16.9 Size: NPS [XX] Wall: [Schedule / wall thickness] End: Butt-welding Quantity: [XX Nos.] Inspection: As per purchase specification Documentation: MTC and required inspection documentation Additional requirements: As applicable to project/code
For a socket-welding fitting, the dimensional requirement would instead reference the applicable ASME B16.11 configuration.
This approach gives the supplier enough information to identify the product without relying on ambiguous commercial terminology.
18. Buying Alloy 825 Fittings for International Projects
For international procurement, the same technical principles apply whether the destination is India, the Gulf, Southeast Asia or South America.
A buyer may also need to specify:
- Delivery location
- Incoterm
- Required documentation
- Inspection agency
- Applicable construction code
- Country-specific regulatory requirements
- Packing requirements
- Marking requirements
- Certificate requirements
- Required delivery schedule
For export enquiries from markets such as Brazil, Argentina, Chile, Colombia, Peru, the UAE, Saudi Arabia, Oman and other Gulf destinations, it is useful to separate the technical specification from the commercial shipping requirement.
For example:
Technical requirement: ASTM B366/B366M + ASME B16.9 + UNS N08825
Commercial requirement: FOB Mumbai/Nhava Sheva or another agreed Incoterm and destination.
The technical specification should not be replaced by a location-based product description.
19. Alloy 825 Fittings: What Buyers Should Confirm Before Ordering
Before issuing a purchase order, confirm:
Material
- Alloy 825
- UNS N08825
- W.Nr. 2.4858 where required
Product specification
- ASTM B366/B366M or applicable material/forging specification
- Applicable ASTM/ASME edition confirmed
- WPNICMC / CRNICMC designation confirmed where applicable
Fitting
- Elbow
- Tee
- Reducer
- Cap
- Coupling
- Other required configuration
Connection
- Butt-welding
- Socket-welding
- Threaded
Dimensional standard
- ASME B16.9
- ASME B16.11
- Applicable MSS standard
Dimensions
- NPS
- Schedule / wall thickness
- Angle
- End preparation
- Other drawing requirements
Quality/documentation
- MTC
- Heat/lot traceability
- PMI if required
- NDE if required
- TPI if required
- EN 10204 documentation if required
- Project-specific inspection requirements
Commercial
- Quantity
- Destination
- Incoterm
- Packing
- Required delivery date
20. The Short Version: Which Standard Do I Need?
If you only remember one thing from this guide, remember this:
ASTM B366/B366M → the nickel-alloy fitting material/product specification.
ASME B16.9 → factory-made wrought butt-welding fitting dimensions and related requirements.
ASME B16.11 → forged socket-welding and threaded fitting dimensions and related requirements.
MSS SP-43 / SP-95 / SP-97 → additional fitting standards that may apply to particular product configurations.
For Alloy 825, identify the material as Alloy 825 / UNS N08825, then specify the appropriate material/product specification, fitting configuration and dimensional standard.
That is much more precise than simply writing "Inconel 825 fittings."
21. Frequently Asked Questions
Is ASTM B366 the standard for Alloy 825 fittings?
ASTM B366/B366M is a key material/product specification for factory-made wrought nickel and nickel-alloy fittings and includes Alloy 825 / UNS N08825 within its grade system. The applicable edition and exact grade designation should be confirmed against the purchase specification.
What is the ASTM grade for Alloy 825 fittings?
For ASTM B366 fittings, Alloy 825 / UNS N08825 is associated with the WPNICMC and CRNICMC designations. The exact designation should be confirmed against the applicable B366 edition and fitting classification.
What is ASME B16.9 used for?
ASME B16.9 covers factory-made wrought butt-welding fittings and provides the applicable dimensional requirements for fittings within its scope. ASME currently lists B16.9-2024.
What is ASME B16.11 used for?
ASME B16.11 is used for forged socket-welding and threaded fittings. The applicable edition should be confirmed against the project and governing code.
Can Alloy 825 fittings be specified with B564 and B16.11?
Depending on the fitting and manufacturing route, a forged material specification such as ASTM B564 may be combined with ASME B16.11. The purchaser should identify the intended material/manufacturing route rather than assuming that B366 and B564 are interchangeable.
Is "Inconel 825" the same as Alloy 825?
"Inconel 825" is a commonly encountered commercial/search term, but procurement documentation should identify the material using a recognized designation such as Alloy 825 / UNS N08825 and the applicable product specification.
What should an Alloy 825 fitting RFQ contain?
At minimum, identify the alloy/UNS designation, material specification, fitting type, dimensional standard, size, wall/schedule requirement, quantity and documentation/inspection requirements. Project-specific requirements should be added where applicable.
Do Alloy 825 fittings automatically include PMI and NDE?
No. PMI and NDE requirements depend on the applicable specification, purchase order and project requirements. They should not be assumed to be universal.
22. Final Buyer Checklist
Before sending an Alloy 825 fitting RFQ, make sure the requirement answers these questions:
What alloy? Alloy 825 / UNS N08825
What material specification? ASTM B366/B366M or the applicable forging/material specification
What fitting? Elbow / tee / reducer / cap / coupling / other
What connection? Butt-welding / socket-welding / threaded
What dimensional standard? ASME B16.9 / B16.11 / applicable MSS standard
What grade/class designation? WPNICMC / CRNICMC where applicable
What size and wall? NPS / schedule / wall thickness
What documentation? MTC / inspection / PMI / NDE / TPI / EN 10204 as required
What commercial terms? Quantity / destination / Incoterm / packing / delivery requirement
If those points are clear, the supplier has a much better chance of understanding exactly what the buyer needs.
Need an Alloy 825 Fitting Quote?
For an Alloy 825 fitting enquiry, provide the UNS designation, fitting type, dimensional standard, size, schedule/wall and required documentation.
See the <a href="/inconel/inconel-825/fitting/">Alloy 825 Fittings product page</a> for the commercial product scope, or use the <a href="/rfq/">Alloy 825 RFQ / enquiry route</a> for a project-specific requirement.
For the broader standards framework, read:
- <a href="/blog/alloy-825-astm-b424-b366-b564/">Alloy 825 Specifications: ASTM B424, B366 & B564</a>
- <a href="/blog/alloy-825-sheet-plate-astm-b424/">Alloy 825 Sheet & Plate: ASTM B424 and ASME SB-424</a>
- Alloy 825 Flanges: ASTM B564, B16.5 & B16.47
- <a href="/inconel/inconel-825/">Alloy 825 Grade / UNS N08825</a>
*Standards editions and project requirements can change. Always confirm the applicable edition, construction code, material route and purchaser specification before placing an order.*