Introduction
A nickel alloy grade cross-reference is a comparison of formal UNS designations, product standards and commonly used trade or commercial names. It helps engineers, inspectors and purchasing teams determine whether terms such as Alloy 625, UNS N06625, Inconel 625 and an ASTM B-series specification refer to the same nominal alloy family and the correct product form.
A cross-reference should not be used as automatic substitution approval. UNS N06625 identifies a chemical-composition family, while ASTM B443, B444 and B446 apply to different forms of Alloy 625. A plate ordered to ASTM B443 is not documented under the same product specification as a seamless pipe ordered to ASTM B444 or a bar ordered to ASTM B446. The grade, form, condition, dimensions, properties, inspection and certificate must all be checked.
Key Takeaways
- UNS identifies an alloy composition family but does not replace the product specification.
- Trade names are useful purchasing references but may be trademarks or supplier-specific descriptions.
- ASTM standards must match the delivered form: plate, bar, seamless tube, welded pipe, forging or wire.
- Nominally similar grades should be compared using actual chemical limits, condition and mechanical requirements.
- The MTC should match the purchase order, heat number, product marking and required inspection scope.
How UNS, ASTM and Trade Names Differ
UNS Designations
The Unified Numbering System assigns a unique alphanumeric number to metals and alloys with established commercial standing. Nickel and nickel-based alloy designations generally use the prefix N, followed by five digits. Examples include N02200 for Nickel 200, N04400 for Alloy 400, N06625 for Alloy 625 and N10276 for Alloy C276.
A UNS number provides a stable identification reference across specifications and industries. It does not define whether the material is plate, tube, bar or forging, and it does not by itself establish dimensions, surface finish, mechanical properties or testing.
ASTM Product Specifications
ASTM specifications define requirements for particular product forms. An alloy may appear in several ASTM standards because plate, bar, tube and forgings require different manufacturing routes and acceptance criteria.
For example, Alloy 625 can be supplied as plate to ASTM B443, seamless pipe and tube to ASTM B444, bar to ASTM B446, welded pipe to ASTM B705 and forgings or fittings to other applicable specifications. The purchase order should state both the UNS number and the correct product standard.
Trade and Commercial Names
Names such as Inconel, Incoloy, Monel and Hastelloy are widely used in engineering and purchasing. Some are registered trademarks associated with particular alloy producers. Other suppliers may use the generic designation “Alloy 625,” “Alloy 825” or “Alloy C276” to describe material meeting the relevant UNS and product specification.
A trade name should therefore be supported by a formal UNS number and standard. A quotation stating only “Hastelloy pipe” is incomplete because Hastelloy C22, C276, B2 and X are different alloys with different chemistry and applications.
Nickel Alloy Grade Cross-Reference Table
The following table provides practical references for commonly purchased nickel and nickel-based alloys. Trade names are shown as common commercial references. Buyers should use the UNS number and applicable product specification as the primary technical identifiers.
| Generic Alloy Name | UNS | Common Trade Reference | General Alloy Type | Specification Note |
|---|---|---|---|---|
| Nickel 200 | N02200 | Nickel 200 | Commercially pure wrought nickel | Confirm product form and carbon limit |
| Nickel 201 | N02201 | Nickel 201 | Low-carbon commercially pure nickel | Do not substitute Nickel 200 without temperature and carbon review |
| Alloy 400 | N04400 | Monel 400 | Nickel-copper alloy | Confirm bar, plate, pipe or wire specification |
| Alloy K-500 | N05500 | Monel K-500 | Age-hardenable nickel-copper alloy | Condition and aging treatment are critical |
| Alloy 600 | N06600 | Inconel 600 | Nickel-chromium-iron alloy | Select the standard according to form and service |
| Alloy 601 | N06601 | Inconel 601 | Nickel-chromium alloy with aluminum addition | Verify high-temperature condition and properties |
| Alloy 617 | N06617 | Inconel 617 | Nickel-chromium-cobalt-molybdenum alloy | Project specifications may control elevated-temperature properties |
| Alloy 625 | N06625 | Inconel 625 | Nickel-chromium-molybdenum-niobium alloy | ASTM standard changes by plate, bar, seamless or welded pipe form |
| Alloy 690 | N06690 | Inconel 690 | High-chromium nickel alloy | Verify nuclear, heat-exchanger or project-specific requirements |
| Alloy 718 | N07718 | Inconel 718 | Precipitation-hardening nickel alloy | Heat treatment, remelting route and property level must be stated |
| Alloy X-750 | N07750 | Inconel X-750 | Age-hardenable nickel-chromium alloy | Several heat-treatment conditions may produce different properties |
| Alloy 800 | N08800 | Incoloy 800 | Nickel-iron-chromium alloy | Do not confuse with 800H or 800HT |
| Alloy 800H | N08810 | Incoloy 800H | Controlled-carbon high-temperature alloy | Carbon, grain size and heat treatment require verification |
| Alloy 800HT | N08811 | Incoloy 800HT | High-temperature controlled-composition alloy | Do not accept generic Alloy 800 documentation |
| Alloy 825 | N08825 | Incoloy 825 | Nickel-iron-chromium-molybdenum-copper alloy | Confirm solution treatment and product-form specification |
| Alloy C22 | N06022 | Hastelloy C22 | Nickel-chromium-molybdenum-tungsten alloy | Do not substitute C276 without media and specification review |
| Alloy C276 | N10276 | Hastelloy C276 | Nickel-molybdenum-chromium-tungsten alloy | Use B575 for plate and B574 for bar where applicable |
| Alloy C2000 | N06200 | Hastelloy C2000 | Nickel-chromium-molybdenum-copper alloy | Confirm copper requirement and exact UNS number |
| Alloy B2 | N10665 | Hastelloy B2 | Nickel-molybdenum alloy | Oxidizing contaminants and fabrication condition require review |
| Alloy B3 | N10675 | Hastelloy B3 | Nickel-molybdenum alloy | Do not assume B2 and B3 have identical processing behavior |
| Alloy X | N06002 | Hastelloy X | Nickel-chromium-iron-molybdenum alloy | Primarily evaluated for high-temperature service and fabrication |
Cross-reference warning: A common trade name and UNS number may identify the same nominal alloy, but product standards can contain different dimensional ranges, test requirements, conditions and mechanical-property tables. Cross-reference does not eliminate the need to compare the full specification.
ASTM Standard Scope by Product Form
| Alloy Family | Plate, Sheet or Strip | Bar or Rod | Seamless Pipe or Tube | Buyer Reminder |
|---|---|---|---|---|
| Alloy 600 / 601 | ASTM B168 | ASTM B166 | ASTM B167 | Check exact UNS grade and condition |
| Alloy 625 | ASTM B443 | ASTM B446 | ASTM B444 | Welded pipe uses a different specification |
| Alloy 800 / 800H / 800HT | ASTM B409 | ASTM B408 | ASTM B407 | Verify N08800, N08810 or N08811 individually |
| Alloy 825 | ASTM B424 | ASTM B425 | ASTM B423 | Confirm seamless or welded construction |
| Alloy C276 / C22-type products | ASTM B575 | ASTM B574 | ASTM B622 | Confirm that the selected UNS is listed in the required edition |
| Alloy 400 | ASTM B127 | ASTM B164 | ASTM B165 | K-500 requires separate grade and condition review |
| Nickel 200 / 201 | ASTM B162 | ASTM B160 | ASTM B161 | Carbon limits distinguish N02200 and N02201 |
The table lists common references, not every possible specification. Welded pipe, welded tube, fittings, forgings, flanges, welding consumables and aerospace products may require other ASTM, ASME, AWS, AMS or project standards. Always confirm the current standard edition and alloy coverage before purchase.
Certificate Checklist for Nickel Alloy Orders
Nickel alloys are often used in pressure, chemical, marine, energy and high-temperature applications. Certificate review should therefore verify both alloy identity and product compliance.
| Certificate Item | What to Check | Typical Problem |
|---|---|---|
| Formal grade | UNS number and alloy designation | Trade family shown without the exact grade |
| Product specification | Correct ASTM, ASME or project standard for the form | Bar or plate specification used for pipe documentation |
| Heat number | Match certificate, product and package markings | Traceability lost after cutting or repacking |
| Chemical analysis | Actual values for all specified elements | Only nominal chemistry or specification limits shown |
| Mechanical properties | Tensile, yield, elongation, hardness and other required results | Values do not correspond to the delivered condition |
| Heat treatment | Solution annealed, annealed, aged or other required condition | Correct grade but wrong condition |
| Supplementary tests | PMI, UT, EC, hydrostatic, corrosion or project tests | Tests assumed to be included but not ordered |
| Certificate type | MTC, EN 10204 3.1, 3.2 or project-defined documentation | Generic certificate supplied instead of specific inspection results |
For a more detailed certificate review process, see the Nickel Alloy MTC Guide.
Common Buyer Mistakes
- Ordering “Inconel,” “Hastelloy” or “Monel” without an exact grade and UNS number.
- Assuming a trade name is the complete technical specification.
- Using a plate standard for bar, tube or pipe material.
- Treating Alloy 800, 800H and 800HT as interchangeable.
- Confusing Nickel 200 with lower-carbon Nickel 201.
- Approving Alloy 625 as a substitute for C276 without corrosion and design review.
- Accepting PMI as proof of complete chemical composition.
- Failing to state the required heat-treatment or aged condition for Alloy 718, X-750 or K-500.
- Ignoring the required standard edition and supplementary project requirements.
- Accepting an MTC whose heat number does not match the delivered material marking.
Nickel Alloy Specification Checklist
- Generic alloy name and recognized trade reference
- UNS number
- Applicable ASTM, ASME, AMS, AWS, EN or project specification
- Standard edition
- Product form: bar, plate, pipe, tube, forging, fitting, wire or flange
- Seamless, welded, forged, rolled or cold-worked manufacturing route
- Dimensions, tolerances and length
- Annealed, solution-treated, aged or other condition
- Surface finish and machining allowance
- MTC or EN 10204 certificate type
- PMI, UT, EC, hydrostatic or corrosion testing
- Heat-number marking and traceability
- Packing, destination and required shipping documents
Related Nickel Alloy Product Families
The following SASA ALLOY pages provide product and grade information for specification review:
- Nickel Alloy Product Range for bars, plates, pipes, fittings, wire and specialty alloys.
- Inconel Alloy Products including Alloy 600, 601, 625, 718 and X-750 product forms.
- Inconel 718 Products for bars, plates, pipe, flanges and forged materials.
- Monel Alloy Products including Alloy 400 and K-500 forms.
- Hastelloy X Products for sheet, plate, bar, pipe, fittings and flanges.
Frequently Asked Questions
What is a nickel alloy grade cross-reference?
It is a comparison of generic alloy designations, UNS numbers, common trade names and applicable product standards. It helps buyers identify the nominal alloy family and determine which additional specification checks are required.
Are Inconel 625 and UNS N06625 the same material?
They refer to the same nominal Alloy 625 composition family. The complete purchase specification must also identify the product form, ASTM or ASME standard, dimensions, condition, properties and inspection requirements.
Are Alloy 800, 800H and 800HT interchangeable?
No automatic interchangeability should be assumed. They have different UNS numbers and controlled chemistry or heat-treatment requirements. The applicable design code, temperature and mechanical-property requirements must be reviewed.
What is the difference between Nickel 200 and Nickel 201?
Nickel 200 is UNS N02200, while Nickel 201 is UNS N02201. Nickel 201 has a lower controlled carbon content and is commonly selected where the service temperature or fabrication requirement makes the lower-carbon grade important.
Does one ASTM standard cover every form of the same nickel alloy?
No. Plate, bar, seamless pipe, welded pipe, tube, forgings and fittings normally use different specifications. For example, Alloy 625 plate, bar and seamless pipe commonly use ASTM B443, B446 and B444 respectively.
What should be checked on a nickel alloy MTC?
Check the UNS number, alloy name, product standard, edition, heat number, dimensions, condition, actual chemistry, mechanical properties and supplementary tests. The heat number should match the material and package markings.
Request a Downloadable Nickel Alloy Specification Checklist
A cross-reference table is the starting point for material identification, not final substitution approval. Send SASA ALLOY the trade name, UNS number, product form, ASTM or ASME specification, dimensions, delivery condition, certificate type and inspection requirements. The technical team can review the requested designations and prepare a downloadable specification checklist for the inquiry.
Post time: Jul-17-2026