Jul 5 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Machinability
Welding
Heat Treatment
Hot Working
Cold Working
Applications
Introduction
Inconel is a group of austenitic nickel-chromium-based super alloys manufactured by Special Metals Corporation. Super alloys are high performance alloys that perform well in environments with very high temperatures.
INCONEL HX is a high-temperature, nickel-chromium-iron-molybdenum alloy. It is matrix-stiffened and provides excellent oxidation resistance, and superior strength of up to 1200°C (2200°F).
The following section explains in detail about super alloy INCONEL HX.
Chemical Composition
The chemical composition of INCONEL HX is outlined in the following table.
|
Element |
Content (%) |
|
Nickel. Ni |
47.5 |
|
Chromium, Cr |
21.8 |
|
Iron, Fe |
18.5 |
|
Molybdenum, Mo |
9 |
|
Cobalt, Co |
1.5 |
|
Tungsten, W |
0.6 |
|
Silicon, Si |
0.5 |
|
Manganese, Mn |
0.5 |
|
Carbon, C |
0.1 |
Physical Properties
The physical properties of INCONEL HX are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
8.22 g/cm3 |
0.297 lb/in3 |
|
Melting point |
1260 - 1355 °C |
2300-2471°F |
Mechanical Properties
The following table shows mechanical properties of INCONEL HX.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
793 MPa |
115000 psi |
|
Yield strength |
345 MPa |
50000 psi |
|
Elastic modulus |
205 GPa |
29700 ksi |
|
Shear modulus |
80 GPa |
11600 ksi |
|
Elongation at break |
45.50% |
45.50% |
|
Hardness, Rockwell B |
90 |
90 |
Thermal Properties
The thermal properties of INCONEL HX are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@0.000-100°C/32-212°F) |
13.3 µm/m°C |
7.39 µin/in°F |
|
Thermal conductivity |
11.6 W/mK |
80.5 BTU in/hr.ft².°F |
Fabrication and Heat Treatment
Machinability
INCONEL HX has to be machined in the annealed condition with carbide or high-speed steel tools and generous supply of sulfur-free cutting fluid. Rigid tools and machines should used to reduce deflection and vibration.
Welding
Weldability of INCONEL HX is rated as good. This super alloy can be welded using metal arc, gas-tungsten-arc, gas-metal-arc, and submerged arc methods. The surfaces to be welded have to properly descaled and cleaned. It is recommended that INCONEL welding electrode 117 and INCONEL filler metal 617 are used.
Heat Treatment
INCONEL HX can be heat treated at 1175°C (2150°F) followed by rapid air cooling or water quenching.
Hot Working
Hot forming of INCONEL HX should be performed by heating to a starting temperature of 1175°C (2150°F). It is advised that the material not be hot worked below 980°C (1800°F).
Cold Working
INCONEL HX can be readily cold worked using slightly higher power than what is applied to austenitic stainless steels. It is recommended that the material be cold worked in the solution-heat-treated condition.
Applications
INCONEL HX is used in the following application areas:
-
Combustion chambers
-
In nuclear engineering
-
For fans, roller hearths and support parts in industrial furnaces
-
Afterburners and tail pipes in aircraft and land-based gas turbine engines