AMS (Aerospace Material Specifications) These are material specifications developed by SAE International, particularly important in the aviation and space industries, and in the production of parts requiring controlled composition, quality, and traceability. They include, among others: stainless and structural steels, nickel superalloys, titanium alloys and requirements for selected technological processes and materials.
In queries, you can find symbols such as: AMS 5643 for steel 17-4PH, AMS 5666 for specific bars and forgings Alloy 625 AMS 5662 / 5663 for different alloy states Alloy 718Grade names alone – e.g., Inconel 718, UNS N07718, or AISI 630 – are not sufficient to define all delivery requirements.
The most important rule: Number AMS defines specific technical specifications, not a general grade. One material may have several AMS standards depending on the form of the product, the state of heat treatment, the method of production and the issuance of the document.
Related articles: American Steel Standards – Overview, SAE system and grade designations, ASTM standards and AISI system.
What does AMS mean and who issues these specifications?
Shortcut AMS means Aerospace Material Specifications. I publish them SAE International as part of the work of committees responsible for aviation materials. Despite their historical aviation nature, AMS documents are also found in procurements for turbine components, power generation, and advanced industrial equipment.
AMS specifications may specify requirements for chemical composition, delivery condition, mechanical properties, surface quality, material inspection, and acceptance procedures. Many of these apply to specific types of products, for example sheets, bars, pipes, forgings or rings.
Important: Not every designation found in aviation is an AMS number. US identifies the alloy, AISI/SAE may specify the steel grade, ASTM: publishes separate specifications, and AMS defines requirements for a specific material and form of product.
AMS, SAE, AISI, UNS, ASTM – what's the difference?
| System | What does it mean in practice? | Example |
|---|---|---|
| SAE / AISI | Designation of the steel family or grade | SAE 4340, AISI 316, AISI 630 |
| US | Uniform material identifier | G43400, S17400, N06625, N07718 |
| ASTM: | Product standard or test method | ASTM A564, ASTM B446, ASTM E8/E8M |
| SAE AMS | Specification of a specific material and product | AMS 6415, AMS 5643, AMS 5666, AMS 5662 |
| EN / W.Nr. | European grade designation and material number | 1.4542, 1.4462, 2.4856, 2.4668 |
How to read AMS 5662P, AMS 5666K or AMS 5643?
For example AMS 5662P can be divided into three elements: AMS – specification family, 5662 – document number, and P – revision designation. The revision letter does not indicate the alloy's chemical group. The document edition required in the order must be clearly stated.
| Element | Meaning | Example |
|---|---|---|
| AMS | Aerospace Materials Specification published by SAE | SAE AMS |
| 5662 | Individual specification number | AMS 5662 – Alloy 718 as delivered |
| P | Another revision of the document | AMS 5662P – 2022 edition/revision |
| Product type | Requirements for bar, sheet, forging, pipe, etc. | AMS 5666 – bars and forgings; AMS 5599 – Alloy 625 flat products |
For example Alloy 718 / UNS N07718 is material, but documents AMS 5662 i AMS 5663 describe different processing and delivery conditions for products in this family. Therefore, changing the AMS number while maintaining the same UNS may change the mechanical requirements.
AMS Specifications for Stainless and Structural Steels
Below are examples of actual AMS specifications for steels used in industries such as aviation. They do not mean that every product of a given grade automatically meets AMS requirements.
| SAE AMS standard | Material / designation | Main Character/Character Requirements | Alfa-Tech Card |
|---|---|---|---|
| AMS 5511 | 304L / UNS S30403 | Sheets, strips and plates, solution heat treated condition | 304 steel family (including 304L) |
| AMS 5524 | 316 / UNS S31600 | Sheets, strips and plates, corrosion-resistant steel | Steel 316 / 316L |
| AMS 5646 | 347 / UNS S34700 | Bars, wire, forgings, mechanical tubes and rings | Steel 347 / 1.4550 |
| AMS 5643 | 17-4PH / AISI 630 / UNS S17400 | Bars, forgings and related product forms | 17-4PH / 1.4542 |
| AMS 5604 | 17-4PH / UNS S17400 | Sheets, strips and plates | 17-4PH / 1.4542 |
| AMS 5659 | 15-5PH / UNS S15500 | Bars, forgings and rings | |
| AMS 5503 | 430 / UNS S43000 | Sheets, strips and plates | AISI 430 / 1.4016 |
| AMS 6415 | SAE 4340 / UNS G43400 | Ni-Cr-Mo Aircraft Steel: Rods, Forgings and Mechanical Tubes | SAE System – 4340 |
| AMS 6409 | SAE 4340 / UNS G43400 | Specification for products with increased purity requirements and in normalized and tempered condition | SAE System – 4340 |
| AMS 6444 | SAE 52100 | Aircraft-grade bearing steel: bars, forgings, mechanical tubes | |
| AMS 6455 | SAE 6150 | Cr-V alloy steel: sheets, strips, plates |
Example 17-4PH: Steel 17-4PH (AISI 630, UNS S17400, EN 1.4542) may appear in the documentation for bars as AMS 5643, and for plates as AMS 5604. It is the same basic type of material, but other product specifications.
SAE AMS for nickel alloys – Inconel 625, 718, Hastelloy X and X-750
In the case of nickel alloys, please provide the designation US and trade name are just the beginning. Requirements for bars, plates, and tubes do not always come from the same AMS document. The table below shows verified correlations.
| Nickel Alloy / UNS | SAE AMS | Character and the most important difference | Alfa-Tech Card |
|---|---|---|---|
| Alloy 625 / Inconel 625 UNS N06625 2.4856 | AMS 5666 | Bars, forgings, rings, extruded products / annealed condition | Alloy 625 |
| Alloy 625 / N06625 | AMS 5599 | Sheets, strips, plates | |
| Alloy 625 / N06625 | AMS 5581 | Seamless and welded pipes | |
| Alloy 718 / Inconel 718 UNS N07718 2.4668 | AMS 5662 | Bars, forgings and rings, solution heat treated; intended for precipitation hardening | Alloy 718 |
| Alloy 718 / N07718 | AMS 5663 | Bars, forgings and rings, solution heat treated and aged | |
| Alloy 718 / N07718 | AMS 5596 | Sheets, strips and plates | |
| Alloy 718 / N07718 | AMS 5589 | Seamless pipes | |
| Hastelloy X / Alloy X UNS N06002 2.4665 | AMS 5536 | Sheets, strips and plates; heat-resistant alloy Ni-Cr-Fe-Mo | Alloy X |
| Inconel X-750 / UNS N07750 | AMS 5667 | Bars, forgings and rings; precipitation hardening alloy |
Alloy 625 and Alloy 718 – do not interchange specifications: For Alloy 625 numbers 5666, 5599 and 5581 are not three names of the same document: they refer to different forms of the product. In turn, for Alloy 718 the designations I 5662 5663 they differ in the required state of heat treatment.
Catalog of nickel alloys and UNS designations related to aerospace and high-temperature materials
The table shows material names and UNS numbers, and they are not automatically assigned an AMS specification. When placing a specific order, you must first check whether the appropriate AMS, ASTM, or other specification exists for the specific product.
| Family / stop | US | EN / W.Nr. | Characteristics and card |
|---|---|---|---|
| Alloy 600 / Inconel 600 | N06600 | 2.4816 | Ni-Cr-Fe |
| Alloy 601 / Inconel 601 | N06601 | 2.4851 | Ni-Cr-Fe-Al |
| Alloy 617 / Inconel 617 | N06617 | 2.4663 | Ni-Cr-Co-Mo |
| Alloy 625 / Inconel 625 | N06625 | 2.4856 | Ni-Cr-Mo-Nb |
| Alloy 718 / Inconel 718 | N07718 | 2.4668 | Ni-Cr-Fe-Nb, precipitation hardening |
| Alloy X / Hastelloy X | N06002 | 2.4665 | Ni-Cr-Fe-Mo |
| Alloy 230 / Haynes 230 | N06230 | 2.4733 | Ni-Cr-W-Mo |
| Alloy 825 / Incoloy 825 | N08825 | 2.4858 | Ni-Fe-Cr-Mo-Cu |
| Alloy C-276 / Hastelloy C-276 | N10276 | 2.4819 | Ni-Mo-Cr-W |
| Alloy C-22 / Hastelloy C-22 | N06022 | 2.4602 | Ni-Cr-Mo-W |
| Monel Alloy 400 | N04400 | 2.4360 | Ni-Cu |
| Monel K-500 | N05500 | 2.4375 | Ni-Cu-Al-Ti |
| Nickel 200 / Nickel 201 | N02200 / N02201 | 2.4066 / 2.4068 | Technically pure nickel – two variants |
| Alloy 800 / 800H / 800HT | N08800 / N08810 / N08811 | 1.4876 / 1.4958 / 1.4959 | Common Ni-Fe-Cr family; different composition, microstructure, and high-temperature performance requirements |
| Inconel X-750 | N07750 | 2.4669 | Ni-Cr-Fe-Ti-Al, precipitation hardening |
Alloy 800 Family: according to the Alfa-Tech list, the 800, 800H and 800HT variants are presented together, with distinction of UNS numbers and requirements: Alloy 800 / 800H / 800HT – comparisonHowever, these are not automatically interchangeable items in the order.
Duplex and superduplex – UNS markings in aerospace and industrial documentation
Duplex steels are primarily found in chemical, marine, and plumbing applications. Any grade can be used in an aerospace project. does not imply the existence of a general AMS number for him. In the table below we show material identifiers, not AMS specifications.
| Genre/family | US | EN / W.Nr. | Reference |
|---|---|---|---|
| Lean Duplex 2101 | S32101 | 1.4162 | LDX 2101 |
| Duplex 2304 | S32304 | 1.4362 | Duplex 2304 |
| Duplex 2205 – variant of UNS S31803 | S31803 | 1.4462 | Duplex 2205 |
| Duplex 2205 – a variant with a narrow composition | S32205 | 1.4462 | Duplex 2205 |
| Duplex 329 | S32900 | 1.4460 | Duplex steel |
| Superduplex 2507 | S32750 | 1.4410 | Superduplex 2507 |
| Superduplex Zeron 100 | S32760 | 1.4501 | Superduplex 1.4501 |
| Superduplex 255 | S32550 | 1.4507 | Duplex 255 / 1.4507 |
Why are there no AMS numbers here? Providing the number UNS S32750 or EN 1.4410 in itself does not prove compliance with a specific aviation specificationFirst, identify the required product and check the standard accepted in the project.
Heat-resistant and creep-resistant steels – material identifiers
Both heat-resistant steels and nickel superalloys are used in the high-temperature industry. The list below is a catalog of material designations: not all items have a universal or commonly used AMS specificationEN markings are provided for guidance only: compliance with product specifications always requires a comparison of chemical and mechanical requirements.
| Type | US | Example EN / W.Nr. | Characteristics / link |
|---|---|---|---|
| AISI 309S | S30908 | 1.4833 | Austenitic Cr-Ni |
| AISI 310S | S31008 | 1.4845 | Family 310 / 1.4845 |
| AISI 310 | S31000 | 1.4845 | Family 310 / 1.4845 |
| AISI 314 | S31400 | 1.4841 | Steel 314 / 1.4841 |
| 253 MA | S30815 | 1.4835 | Steel 253 MA / 1.4835 |
| 304H | S30409 | Variant with increased carbon content | |
| 316H | S31609 | High temperature variant | |
| 321H | S32109 | 1.4878 | Titanium Stabilized Steel – Separate Requirements |
| 347H | S34709 | 1.4912 | Niobium stabilized steel – separate requirements |
AMS and the form of the material: rod, forging, sheet, pipe, ring
Even when the material is the same, different molds may require different manufacturing and testing procedures. For example:
| Material | Flat products | Rods / forgings / rings | Pipes |
|---|---|---|---|
| Alloy 625 / N06625 | AMS 5599 | AMS 5666 | AMS 5581 |
| Alloy 718 / N07718 | AMS 5596 | AMS 5662 or 5663 – depending on condition | AMS 5589 |
| 17-4PH / S17400 | AMS 5604 | AMS 5643 | Check the separate required project specification |
| Steel 4340 / G43400 | Check the norm of a specific character | AMS 6415; in a specific variant AMS 6409 | AMS 6415 – Mechanical Tubes within the Scope of the Standard |
In your order, do not simply write "Inconel 625 AMS" if you are ordering a bar with a specific delivery condition. full AMS number, required edition, material form, dimensions and additional tests.
Heat treatment, metallurgical purity and acceptance certificates
AMS specifications often distinguish between conditions such as solution heat treated (after saturation), annealed (annealed) or precipitation heat treated / aged (after precipitation strengthening). For selected materials, the method of remelting is also important – e.g. Vim (vacuum induction melting), VAR (arc remelting in a vacuum) or ESR (electroslag remelting).
For AMS materials, don't assume that a simple chemical composition certificate will suffice. The scope of inspection and required confirmations depend on the specifications and contract, including customer requirements for batch traceability, origin, non-destructive testing, and quality management system.
Note regarding VIM, VAR and ESR: Manufacturing or smelting technologies are not automatically equivalent. VIM = vacuum induction melting, VAR = vacuum arc remelting, ESR = electroslag remeltingThe required technology should be verified in the specific specification and order.
How to save AMS material in a request for quotation?
Example of a correct order description for a nickel alloy rod:
Order example: Alloy 625 / UNS N06625 / EN 2.4856 – round bar, material requirements according to SAE AMS 5666 (issue indicated), annealed condition, diameter and length as ordered, batch control and traceability documents required.
- Steel or alloy grade: e.g. UNS N07718, S17400 or G43400.
- Full SAE AMS number with revision: not the abbreviation AMS itself.
- Product form and exact dimensions: sheet metal, pipe, rod, forging, ring.
- Delivery condition / heat treatment: annealed, solution treated, aged, if applicable.
- Additional requirements: manufacturing method, permissible defects, tolerances, NDT, samples.
- Receipt and documents: customer requirements regarding certification, quality control and traceability.
Frequently Asked Questions – FAQ
What does AMS mean in steel designation?
Aerospace Material Specifications – a group of SAE International specifications defining material requirements for specific products, delivery states and processes.
Is UNS N06625 the same as AMS 5666?
No. N06625 is the alloy identifier for Alloy 625. AMS 5666 specifies the requirements for specific products made from this alloy.
What is the difference between AMS 5662 and AMS 5663?
Both documents refer to Alloy 718, but differ, among other things, in the heat treatment status of the products.
Can AMS 5599 be applied to Alloy 625 rod?
AMS 5599 applies to flat products. For specific Alloy 625 bars and forgings, AMS 5666 is the typical reference.
Are AISI 630 and AMS 5643 interchangeable?
No. AISI 630 is a type designation for 17-4PH steel, while AMS 5643 describes the requirements for specific products.
Does AMS cover duplex and superduplex permanently?
The scope of required documentation varies by project. UNS numbers for duplexes do not automatically imply the existence or compliance with a specific AMS standard.
Does the AMS specification guarantee the use of the material in every aircraft?
No. Material compatibility is only one element of qualification. Design documentation, customer requirements, and proper acceptance procedures also count.
Are ASTM and AMS the same?
No. Both families may include material specifications, but they are developed by different organizations and may require different testing or delivery methods.
Is an AMS number enough to order material?
No. You must also indicate the species, form, dimensions, delivery condition, appropriate AMS issue, and acceptance requirements.
Source documents and information about AMS releases
This list is for technical information purposes only and does not replace the original, current standards. Below are links to the SAE International catalog and sample specification sheets. All links except Alfa-Tech are marked as nofollow.
- SAE – Material Specifications catalog
- SAE AMS 5511L – 304L steel, flat products
- SAE AMS 5524P – 316 steel, flat products
- SAE AMS 5666 – Alloy 625, Bars and Forgings (Historical Revision F)
- SAE AMS 5662P – Alloy 718, solution heat treated
- SAE AMS 5663P – Alloy 718, aged
- SAE AMS 5604 – 17-4PH, flat products
- SAE AMS 6415 – SAE 4340
Summary – How to use SAE AMS when selecting steels and alloys?
specifications AMS are particularly useful where consistent quality, traceability, and strict process control are essential. Materials marked as 17-4PH, Alloy 625, or SAE 4340, however, must be ordered not by name alone, but by a list. species + AMS standard + product type + delivery status + document issue.
Don't know the correct AMS number or are you looking for material with similar requirements? Send the species designation, standard, dimensions and type of product to the address kontakt@alfa-tech.com.pl. See also American steel standards.