Room-Temperature Mechanical Properties of Incoloy 800 (UNS N08800)
1. Tensile Strength
Definition: The maximum stress a material can withstand before undergoing tensile fracture under axial loading.
Typical Value: 550–650 MPa
Minimum Specification Requirement:
ASTM B409/B408/B564: ≥ 450 MPa
EN 10095 (Grade X5NiCrAlTi31-20, 1.4876): ≥ 450 MPa
GB/T 24511 (Grade NS1101): ≥ 440 MPa
Note: Higher tensile strength values may be observed in cold-worked variants of Incoloy 800, but the annealed state is preferred for most high-temperature applications due to its balanced performance.
2. Yield Strength (0.2% Offset)
Definition: The stress at which a material exhibits a permanent plastic deformation of 0.2% relative to its original gauge length.
Typical Value: 200–270 MPa
Minimum Specification Requirement:
ASTM Standards: ≥ 170 MPa
EN 10095: ≥ 170 MPa
GB/T 24511: ≥ 170 MPa
Note: Yield strength is a critical parameter for structural design, as it determines the maximum load a component can bear without permanent deformation.
3. Elongation (in 50 mm Gauge Length)
Definition: The percentage of permanent elongation of a material's gauge length after tensile fracture, reflecting its ductility.
Typical Value: 35–45%
Minimum Specification Requirement:
ASTM Standards: ≥ 30%
EN 10095: ≥ 30%
GB/T 24511: ≥ 30%
Note: High elongation makes Incoloy 800 suitable for forming processes such as bending, rolling, and deep drawing, which are commonly used in manufacturing heat exchangers and furnace components.
4. Hardness
Brinell Hardness (HBW, 500 kgf load, 10 mm ball): 130–180 HBW
Rockwell Hardness (HRB, 100 kgf load, 1/16 inch ball): 60–80 HRB
Note: Hardness values are inversely related to ductility; higher hardness usually corresponds to lower elongation, especially in cold-worked material states.
5. Additional Mechanical Property (Reduction of Area)
Definition: The percentage of the original cross-sectional area reduced after tensile fracture.
Typical Value: 60–70%
Minimum Specification Requirement: ≥ 40% (ASTM and EN standards)
