The nimonic 80A high temperature resistance wire is an age hardenable nickel chromium allow wire, high strength due to presence of titanium, aluminum and carbon made for service at different temperatures about 815oC or 1500ooF. It is made by high frequency melting and casting in the presence of air for extruded forms. The electroslag refined alloy material is utilized for forging.
The nimonic 80A wire is employed in making the gas turbine components like blades, rings and discs, bolts, nuclear boiler tube parts, die casting and automobile’s valves. The chemical composition of nimonic 80A high temperature resistance wire is mentioned here below:
The physical properties of nimonic 80A wire are provided in the below table:
|Melting Range, oC or oF||1320-1365 or 2410-2490|
|Mass Susceptibility||5.85 x 10-6 at 1000 gauss|
|Volume Susceptibility||4.78 x 10-5 at 1000 gauss|
|Magnetic Permeability||1.000601 for 200-2000 oersted|
The density of alloy is concluded on the extruded bar, immediately formed and extruded part, immediately cold drawn at the heat processing of 8 hours at temperature of 1080oC or 1976oF then air quenched plus heat processing for 6 hours at temperature of 700oC or 1292oF the air quenched. The liquefaction temperature is calculated by the inverse cooling method and the solidification by the metallographic tests. The accuracy is concluded by ±5oC or 9oF for liquefaction and +0 at -10oC or 18oF for the solidification.
The specific heat properties of alloy are provided in the below table:
|oC||oF||J/kg oC||Btu/lb oF|
The thermal conductivity of alloy is shown in the below table:
The alloy is cold drawn sheet, heat processed for 2 to 3 minutes at 1150oC or 2102oF then fluidized bed cooled and heating for 1 hour at 925oC or 1697oF, air quenched and heating for 4 hours at 750oC or 1382oF then air cooled. The mean coefficient of thermal expansion properties of alloy are shown below:
|68 – 212||7.1||7.1|
The creep resistance offered by the nimonic 80A high temperature resistance wire is analyzed. The total plastic strain information is calculated on the extruded bar. The creep resistance on the extruded bar, then forged is calculated by following the Larson-Miller presentations and Graham and Walles techniques.