AMS 5893
AMS 5893 covers Incoloy 909 (UNS N19909) controlled-thermal-expansion nickel-iron-cobalt alloy in plate form — the thick-section product for machined structural components, flanges, and thick-wall parts in gas turbine engines where dimensional stability across the 70–1200°F operating range is critical. Plate material from AMS 5893 is used for machined engine structural flanges, rotor retention rings, and thick structural members where the machined geometry, rather than formed sheet, is the production route and the matching low CTE of the 909 alloy is the governing design requirement.
The alloy properties and heat treatment are identical to AMS 5884 bar and AMS 5892 sheet — the distinction between the three AMS 909 specifications is product form only. AMS 5893 plate covers thicknesses from 0.188 inch to 3.000 inches, enabling machining of complex flange and structural sections that cannot be produced from bar without excessive stock removal.
Mechanical Properties (AMS 5893 — Incoloy 909 Plate, Solution-Treated)
- Minimum Tensile Strength (solution-treated): 100,000 psi (689 MPa)
- Minimum Yield Strength (solution-treated): 50,000 psi (345 MPa)
- After Age Hardening: Min yield 130,000 psi, Min UTS 155,000 psi
- Minimum Elongation (solution-treated): 30%
- CTE (70–1200°F): ≈ 7.7 × 10⁻⁶/°F
- Plate thickness: 0.188 inch to 3.000 inches
AMS 5893 plate is supplied solution-treated (1800°F, water quench) for machining. Rough machining is performed in the solution-treated condition; finish machining and age hardening sequence (1400°F/8h + 1200°F/8h) are coordinated so that final aging occurs with minimum stock removal remaining — minimizing distortion from aging volume change in thick section components. For precision flange components, fixture aging with clamping to a reference surface is sometimes specified. Plate straightness and flatness requirements are per AMS 5893.
- Gas turbine engine structural flanges requiring matched CTE to adjacent ceramic or titanium components
- Machined rotor retention rings and structural retaining components in engine hot sections
- Thick-section structural hardware in gas turbine compressor cases
- Precision machined instrumentation and sensing component bodies in gas turbines
- Engine hot-section structural blocks requiring low-CTE Ni-Fe-Co alloy in plate form
- Test stand structural fixtures for gas turbine development requiring CTE control
AMS 5892 — Incoloy 909 Sheet
Incoloy 909 sheet and strip — the thin-section formed product companion for sealing elements and sheet metal fabrications in 909 CTE alloy.
AMS 5884 — Incoloy 909 Bar
Incoloy 909 bar and billet — the machined round bar form for sealing rings and shafts in the same 909 controlled-CTE alloy.
Certified Material for Critical Service
AMS 5893 mill test reports document Incoloy 909 chemistry, solution-treated condition, and mechanical properties. Plate dimensions (thickness, width, length, flatness) and surface condition are per AMS 5893 tolerances. Compared with AMS 5884 (bar) and AMS 5892 (sheet), the plate specification covers the thick-section product form where bar diameters would be insufficient or wasteful. All three specifications document the same 909 alloy chemistry and solution-treated baseline properties.