AMS 5662, AMS 5663 and AMS 5664 cover closely related Inconel 718 compositions and wrought forms, but they do not describe the same supplied condition. Choosing by alloy name alone can leave a purchaser with unaged stock, the wrong solution treatment or test results that do not represent the final part.
Important: SAE standards are revised. The current purchase-order revision and drawing control. This guide summarizes the publicly stated scope of AMS5662P, AMS5663P and AMS5664G; obtain the complete licensed document before ordering or accepting material.
The Short Answer
AMS 5662 covers Alloy 718 bar, forgings, rings and stock solution treated at 1775°F (968°C) and precipitation hardenable. AMS 5663 covers comparable forms already solution and precipitation heat treated. AMS 5664 covers solution-treated, precipitation-hardenable material using the higher 1950°F (1066°C) solution route and also includes extrusions in its title.
Specification Comparison
| Item | AMS 5662P | AMS 5663P | AMS 5664G |
|---|---|---|---|
| Alloy family | Inconel 718-type Ni-Cr-Fe-Nb-Mo-Ti-Al | Same | Same |
| Principal solution treatment | 1775°F (968°C) | 1775°F (968°C) | 1950°F (1066°C) |
| Supplied precipitation condition | Precipitation hardenable; buyer/fabricator may age later | Solution and precipitation heat treated | Precipitation hardenable; buyer/fabricator may age later |
| Public scope forms | Bars, forgings, flash-welded rings and stock | Bars, forgings, flash-welded rings and stock | Bars, forgings, extrusions, flash-welded rings and stock |
| Procurement question | Who will perform final aging? | Do supplied properties meet final-part needs? | Does the design require the higher solution route? |
The current public SAE pages state size limits for finished product around 10 inches (254 mm) maximum cross-section and roughly 78.54 square inches (503 cm²), while stock for forging or rings may have separate scope. Read the purchased revision for exact wording and exceptions.
AMS 5662: Solution Treated, Ready for Aging
AMS 5662 uses a 1775°F (968°C) solution treatment and supplies precipitation-hardenable material. It is useful when the purchaser wants to machine or form in the softer solution-treated state and perform final aging after processing.
The purchase plan must identify who owns final aging and final-property verification. A certificate showing compliance with AMS 5662 does not mean the delivered material already possesses AMS 5663 aged tensile properties.
AMS 5663: Solution and Precipitation Heat Treated
AMS 5663 is the straightforward choice when bar, forging or ring is required in the solution-and-aged condition covered by the standard. The mill or heat treater performs the defined treatment and reports the required properties.
This can reduce downstream heat-treatment risk, but it may make machining and forming more difficult. Any subsequent high-temperature process or weld repair must be reviewed because it can change the certified condition.
AMS 5664: Higher Solution Temperature
AMS 5664 uses a 1950°F (1066°C) solution treatment and supplies precipitation-hardenable material. The higher solution temperature changes grain structure, dissolution of phases and the balance between tensile, creep/rupture and notch behavior. It is not simply “AMS 5662 at a hotter temperature.”
The route may support applications where higher-temperature properties are important, but the component specification must state the required aging cycle and tests. Substitution between 5662 and 5664 requires engineering approval.
For the metallurgical background, read Inconel 718 Heat Treatment.
Why Product Form and Process Sequence Matter
The same heat can respond differently in small bar, a large forging or a flash-welded ring because cooling rate, working ratio and grain structure differ. A robust route aligns:
- starting stock specification;
- forging reduction and temperature;
- solution treatment;
- rough and finish machining;
- precipitation aging;
- welding or repair; and
- final NDE and mechanical testing.
If a finished drawing simply says “Inconel 718 per AMS 5662, fully heat treated,” it combines two ideas without defining the final aged requirement. Add the precise final condition or reference a drawing heat-treatment specification.
For shape-specific controls, see the Nickel Alloy Forgings Specification Guide.
What to Verify on the MTC
- Exact AMS number and revision.
- Product form and dimensional scope.
- Heat number and melt/remelt route.
- Actual chemical analysis.
- Solution-treatment temperature, time and cooling.
- Aging cycle for AMS 5663 or separately ordered final aging.
- Tensile results, test temperature and orientation.
- Hardness and grain-size data when required.
- Ultrasonic, penetrant or other NDE results.
- Traceability after forging, ring welding or cut-length processing.
The certificate should separate material tested in the supplied condition from properties measured after a laboratory aging cycle. Those are not the same evidence.
Common Ordering Errors
Treating 5662 and 5663 as Equivalent
5662 is ready to be precipitation hardened; 5663 is already solution and precipitation treated. Machining condition, hardness and acceptance evidence differ.
Calling 5664 the “Aged Ring Specification”
Current AMS 5664 public scope describes solution-treated, precipitation-hardenable material, not simply an aged flash-welded-ring specification.
Omitting Revision and Size
Revisions change technical wording and scope. Large cross-sections may fall outside the finished-product size range.
Reusing Room-Temperature Values for Design
Use aerospace design allowables and the controlling part specification. Supplier typical data are not design allowables.
RFQ Checklist
- AMS 5662P, 5663P or 5664G—or the revision required by the drawing.
- Bar, forging, extrusion, flash-welded ring or stock form.
- Dimensions, machining allowance and quantity.
- Melt route, remelt route and source-approval requirements.
- Supplied and final heat-treatment condition.
- Party responsible for final aging.
- Mechanical tests, temperature, orientation and sampling location.
- Grain-flow, macroetch and microstructure requirements.
- UT class, penetrant inspection and acceptance criteria.
- Special-process approvals and heat-treater qualification.
- Marking, traceability and certificate format.
Frequently Asked Questions
Is AMS 5662 already aged?
No. It covers solution-treated, precipitation-hardenable material. Final aging must be defined if the finished part requires aged properties.
What is the main difference between AMS 5662 and 5663?
Both use the 1775°F solution route, but 5663 is supplied after precipitation heat treatment while 5662 is not.
What distinguishes AMS 5664?
It uses a 1950°F solution treatment and remains precipitation hardenable. Its public title also includes extrusions.
Can AMS 5663 material be machined?
Yes, but it is harder and stronger than solution-treated 5662 material. Tooling, speed, feed and distortion control must reflect the aged condition. See Machining Inconel 625 vs 718.
Can one certificate list multiple AMS specifications?
Only when the heat, product, condition, tests and documentation independently satisfy each listed specification. Similar chemistry alone is insufficient.
Final Recommendation
Select the AMS number by product form, solution route and delivered aging condition—not by alloy name alone. Send J&A Alloy the drawing, required revision, dimensions, melt route, final aging responsibility, test orientation, NDE class and certification requirements.
