Nov 15 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesThermal PropertiesOther DesignationsFabrication and Heat Treatment Cold Working Welding Forging Forming Machinability Hardening Heat Treatment AgingApplications
Introduction
Super alloys or high performance alloys are available in a variety of shapes and contain elements in different combinations to obtain a specific result. These alloys are of three types that include iron-based, cobalt-based and nickel-based alloys. The nickel-based and cobalt-based super alloys are available as cast or wrought based alloys according to composition and application.
Super alloys have good oxidation and creep resistance and can be strengthened by precipitation hardening, solid-solution hardening and work hardening methods. They can also function under high mechanical stress and high temperatures and also in places that require high surface stability.
HASTELLOY(r) X alloy is a wrought nickel base alloy comprising oxidation resistance and high temperature strength. This alloy is resistant to stress-corrosion cracking.
The following datasheet provides an overview of HASTELLOY(r) X alloy.
Chemical Composition
The chemical composition of HASTELLOY(r) X alloy is outlined in the following table.
| Element |
Content (%) |
| Cr, Chromium |
20.5-23 |
| Fe, Iron |
17-20 |
| Mo, Molybdenum |
8-10 |
| Mn, Manganese |
1 max |
| Si, Silicon |
1 max |
| Ti, Titanium |
0.15 max |
| Co, Cobalt |
0.5-2.5 |
| Al, Aluminum |
0.5 max |
| Cu, Copper |
0.5 max |
| C, Carbon |
0.05-0.15 |
| P, Phosphorus |
0.04 max |
| S, Sulfur |
0.03 max |
| W, Tungsten |
0.2-1 |
| B, Boron |
0.008 max |
| Ni, Nickel |
Remainder |
Physical Properties
The following table shows the physical properties of HASTELLOY(r) X alloy.
| Properties |
Metric |
Imperial |
| Density |
8.220 g/cm³ |
0.297 lb/in³ |
| Melting point |
1316°C |
2400°F |
Mechanical Properties
The mechanical properties of HASTELLOY(r) X alloy are displayed in the following table.
| Properties |
Metric |
Imperial |
| Tensile strength |
755 MPa |
109.5 Ksi |
| Yield strength |
385 MPa |
55.9 Ksi |
| Elastic modulus |
205 GPa |
29.8 psi |
| Reduction of area |
22% |
22% |
| Hardness, Rockwell B (converted from Brinell hardness) |
87 |
87 |
Thermal Properties
The thermal properties of HASTELLOY(r) X alloy are given in the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient |
13.0 µm/m°C |
7.2 µin/in°F |
| Thermal conductivity |
9.1 W/mK |
63 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to HASTELLOY(r) X alloy are as follows.
| AISI 680
| AMS 5587
| AMS 5754
| ASTM B435
| ASTM B572 |
| AMS 5588 |
AMS 5536 |
AMS 5798 |
ASTM B619 |
ASTM B366 |
| ASTM B622 |
ASTM B626 |
PWA 1038 |
DIN 2.4665 |
DIN 2.4603 |
| GE B50A436 |
GE B50A463 |
GE B50T83A |
GE B50TF24 |
GE B50TF25 |
| GE B50TF31 |
|
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Fabrication and Heat Treatment
Cold Working
HASTELLOY(r) X alloy can be readily cold worked and requires a large amount of forming pressure due its high stiffness characteristic. Solution annealing can be performed after this alloy is cold worked.
Welding
Welding processes suitable for HASTELLOY(r) X alloy include shielded metal arc welding, resistance welding and TIG or MIG. Usage of a corresponding filler metal is recommended whereas post heating and preheating are not recommended.
Forging
Conventional methods are used for hot forging HASTELLOY(r) X alloy.
Forming
Standard processing and tooling methods are used for forming different product forms of HASTELLOY(r) X alloy.
Machinability
Conventional methods are used for machining HASTELLOY(r) X alloy.
Hardening
HASTELLOY(r) X alloy can be hardened by cold working and to a limited extent by aging. This alloy cannot be hardened by the standard heating methods.
Heat Treatment
HASTELLOY(r) X alloy is mostly solution annealed at 1177°C (2150°F) and then cooled rapidly.
Aging
HASTELLOY(r) X alloy is first solution heat treated and then aged at 649-871°C (1200-1600°F). Increase in hardness and strength can be obtained when this alloy is under the aging temperature for prolonged hours.
Applications
HASTELLOY(r) X alloy is used industrial furnace applications such as structural components. This alloy is also used in gas turbines in the hot combustor zone sections and petrochemical process equipment.