Nov 15 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Heat Treatment
Forging
Hot Working
Cold Working
Annealing
Hardening
Applications
Introduction
Super alloys are also referred to as high performance alloys. They have good creep and oxidation resistance, and are utilized where high surface stability is required. They also have an ability to function under high temperatures and mechanical stress. They can be strengthened by solid-solution hardening, work hardening, and precipitation hardening. They are divided into three groups such as iron-based, nickel-based, and cobalt-based alloys.
Incoloy 800HT™ is a nickel-iron-chromium alloy, and also a modified version of alloy 800. It has high creep-rupture strength. The following datasheet gives an overview of Incoloy 800HT™.
Chemical Composition
The chemical composition of Incoloy 800HT™ is outlined in the following table.
|
Elements |
Content (%) |
|
Iron, Fe |
≥ 39.5 |
|
Nickel, Ni |
30- 35 |
|
Chromium, Cr |
19-23 |
|
Manganese, Mn |
≤ 1.50 |
|
Silicon, Si |
≤ 1 |
|
Copper, Cu |
≤ 0.75 |
|
Titanium, Ti |
0.15-0.60 |
|
Aluminum, Al |
0.15-0.60 |
|
Carbon, C |
0.060-0.10 |
|
Sulfur, S |
≤ 0.015 |
Physical Properties
The physical properties of Incoloy 800HT™ is displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
7.94 g/cm³ |
0.287 lb/in³ |
|
Melting point |
1357-1385 °C |
2475-2525 °F |
Mechanical Properties
The following table shows the mechanical properties of Incoloy 800HT™.
|
Properties |
Metric |
Imperial |
|
Tensile strength (annealed) |
560 MPa |
81200 psi |
|
Yield strength (annealed) |
250 MPa |
36300 psi |
|
Elongation at break (annealed prior to test) |
45% |
45% |
Thermal Properties
The thermal properties of Incoloy 800HT™ are given in the following table.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@ 20-100°C/68-212°F) |
14.4 µm/m°C |
8.00 µin/in°F |
|
Thermal conductivity |
11.5 W/mK |
79.8 BTU in/hr. ft².°F |
Other Designations
Other designations that are equivalent to Incoloy 800HT™ include:
-
ASTM B407
-
ASTM B408
-
ASTM B409
-
DIN 1.4876
-
DIN 1.4959
Fabrication and Heat Treatment
Machinability
Incoloy 800HT™ can be machined using conventional machining methods which are used for iron based alloys. Machining operations are performed using machining coolants. High-speed operations such as grinding, turning, or milling, are performed using water-base coolants. Drilling, broaching, tapping, or boring can be performed using heavy lubricants.
Forming
Incoloy 800HT™ can be formed using all conventional techniques.
Welding
Incoloy 800HT™ is welded using shielded metal-arc welding, gas-tungsten arc welding, gas metal-arc welding, and submerged-arc welding methods.
Heat Treatment
Incoloy 800HT™ can be heat treated by annealing. However, it does not harden by heat treatment.
Forging
Incoloy 800HT™ is forged at 1010 to 1205°C (1850 to 2200°F).
Hot Working
Incoloy 800HT™ is hot worked at 872 to 1205°C (1600 to 2200°F).
Cold Working
Incoloy 800HT™ can be cold worked using standard tooling.
Annealing
Incoloy 800HT™ is annealed at 1149°C (2100°F) followed by cooling.
Hardening
Incoloy 800HT™ is hardened by cold working only.
Applications
Incoloy 800HT™ is used in petrochemical equipments for heat exchangers.