Jul 24 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
Machinability
Forming
Welding
Heat Treatment
Forging
Cold Working
Hardening
Other Designations
Applications
Introduction
Pyromet A-286 alloy is an iron-base superalloy that offers high ductility in notched sections. It has higher notched rupture strength when compared to other commercial alloys with comparable high temperature properties. The alloy can be precipitation hardened and strengthened by heat treatment.
The following sections will discuss in detail about Pyromet Alloy A-286.
Chemical Composition
The chemical composition of Pyromet alloy A-286 is outlined in the following table.
|
Element |
Content (%) |
|
Nickel, Ni |
24.5-27 |
|
Chromium, Cr |
14-16 |
|
Titanium, Ti |
1.5-2.5 |
|
Molybdenum, Mo |
1-1.6 |
|
Manganese, Mn |
1-1.5 |
|
Aluminum, Al |
0.1-0.3 |
|
Carbon, C |
0.08 |
|
Boron, B |
0.02 |
|
Iron, Fe |
Balance |
Physical Properties
The following table shows the physical properties of Pyromet A-286 alloy.
|
Properties |
Metric |
Imperial |
|
Density |
7.92 g/cm3 |
0.286 lb/in3 |
|
Melting point |
1370-1430°C |
2500-2610°F |
Mechanical Properties
The mechanical properties of Pyromet A-286 alloy are displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Tensile strength (Solution treated) |
620 MPa |
89900 psi |
|
Yield strength (Solution treated) |
275 MPa |
39900 psi |
|
Elongation at break (Solution treated) |
40% |
40% |
Thermal Properties
The thermal properties of Pyromet A-286 alloy are given in the following table.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@20-93°C/68-199°F) |
16.5 µm/m°C |
9.17 µin/in°F |
|
Thermal conductivity |
15.1 W/mK |
105 BTU.in/hrft².°F |
Fabrication and Heat Treatment
Machinability
Pyromet A-286 alloy can be readily machined by standard methods. Cemented carbide tools are best-suited for high cutting rates.
Forming
This alloy can be cold or hot formed using conventional techniques.
Welding
Welding of Pyromet A-286 alloy is similar to that of stainless steel. Preheating or post welding heat treatment is not required.
Heat Treatment
Pyromet A-286 alloy is solution annealed at 982°C (1800°F), oil quenched and air cooled.
Forging
Light forging can be performed in the temperature range of 871 to 1010°C (1600 to 1850°F). Heavy forging can be carried out at temperatures in the range of 1010 to 1024°C (1850 to 2200°F).
Cold Working
The alloy can be readily cold worked in a manner similar to that of the austenitic stainless steels.
Hardening
Hardening of Pyromet A-286 alloy can be accomplished by cold working.
Other Designations
Other designations that are equivalent to Pyromet A-286 alloy include the following:
|
AISI 660 |
AMS 5737 |
ASTM A638 Grade 660 |
|
AISI 662 |
AMS 5804 |
DIN 1.4943 |
|
AMS 5525 |
AMS 5805 |
DIN 1.4944 |
|
AMS 5726 |
AMS 5853 |
GE B50T1181 |
|
AMS 5731 |
AMS 5858 |
GE B50T12 |
|
AMS 5732 |
AMS 5895 |
GE B50T81 |
|
AMS 5734 |
ASTM A453 Grade 660 |
SPS M250 |
Applications
The following are the list of applications of Pyromet A-286 alloy:
-
Jet engines
-
Superchargers
-
Turbine wheels and blades, frames, casings
-
Afterburner parts and fasteners.