Nov 25 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
Applications
Introduction
Super alloys contain a number of elements in a variety of combinations to obtain the desired result. They are also known as high performance alloys. Solid-solution hardening, precipitation hardening, and work hardening are performed for increasing the strength of super alloys. They have an ability to function under high mechanical stress and temperatures, and also where high surface stability is required. They are further classified into three types such as cobalt-based, nickel-based, and iron-based alloys.
Haynes(r) X-750 alloy is a nickel-chromium precipitation-hardening alloy. It has high ductility and excellent properties at cryogenic temperatures. The following datasheet provides more details about Haynes(r) X-750 alloy.
Chemical Composition
The chemical composition of Haynes(r) X-750 alloy is outlined in the following table.
|
Element |
Content (%) |
|
Chromium, Cr |
14-17 |
|
Iron, Fe |
5-9 |
|
Titanium, Ti |
2.25-2.75 |
|
Manganese, Mn |
1 max |
|
Niobium, Nb |
0.7-1.2 |
|
Copper, Cu |
0.5 max |
|
Silicon, Si |
0.5 max |
|
Aluminum, Al |
0.4-1 |
|
Carbon, C |
0.08 max |
|
Sulfur, S |
0.01 min |
|
Nickel, Ni |
Remainder |
Physical Properties
The physical properties of Haynes(r) X-750 alloy are given in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
8.26 g/cm³ |
0.298 lb/in³ |
|
Melting point |
1413°C |
2575°F |
Mechanical Properties
The following table shows the mechanical properties of Haynes(r) X-750 alloy.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
1325 MPa |
192.2 ksi |
|
Elongation at break (in 51 mm) |
23.60% |
23.60% |
|
Reduction of area |
42% |
42% |
Thermal properties
The thermal properties of Haynes(r) X-750 alloy are displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (at 20-500°C/70-800°F) |
14.3 µm/m°C |
7.8 µin/in°F |
|
Thermal conductivity (at 200°C/400°F) |
14.1 W/mK |
98 BTU in/hr.ft².°F |
Other Designations
Other designations that are equivalent to Haynes(r) X-750 alloy include:
|
AISI 688 |
AMS 5598 |
AMS 5670 |
AMS 5747 |
GE B50TF1232 |
|
AMS 5542 |
AMS 5667 |
AMS 5671 |
ASTM B637 |
GE B50YP44 |
|
AMS 5582 |
AMS 5668 |
AMS 5698 |
DIN 2.4669 |
MIL N-24114 |
|
AMS 5583 |
AMS 5669 |
AMS 5699 |
DIN 2.4699 |
MIL N-7786 |
|
|
|
|
|
|
Fabrication and Heat Treatment
Machinability
Haynes(r) X-750 alloy 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 are performed using heavy lubricants.
Forming
Haynes(r) X-750 alloy can be formed using all conventional techniques.
Welding
Haynes(r) X-750 alloy is welded using shielded metal-arc welding, gas-tungsten arc welding, gas metal-arc welding, and submerged-arc welding methods.
Heat Treatment
Haynes(r) X-750 alloy is heat treated by annealing at 885 to 1149°C (1625 to 2100°F).
Forging
Haynes(r) X-750 alloy is forged at temperatures ranging from 1205 to 1038°C (2200 to 1900°F).
Hot Working
Haynes(r) X-750 alloy is hot worked at temperatures ranging from 983 to 1038°C (1800 to 2200°F).
Cold Working
Haynes(r) X-750 alloy can be cold worked using standard tooling. Soft die materials such as bronze and zinc alloys, are used for providing good finish and reducing galling problems.
Annealing
Haynes(r) X-750 alloy is annealed at 983 to 1038°C (1800 to 2000°F) followed by cooling.
Applications
Haynes(r) X-750 alloy is mainly used in structural members of hot sections of gas turbines such as ducts, thrust reversers, discs.