This superalloy is initially melted using Vacuum Induction Melting (VIM) techniques. This practice is followed by Vacuum Arc Remelting (VAR). The melt practice is an enhancement of the standard melt practice for ASTM F-562 material yielding much lower inclusion counts. This results in improved fatigue life of as-drawn wire by as much as 800%.
ASTM F562 | |
---|---|
Carbon | 0.025 |
Manganese | 0.15 |
Silicon | 0.15 |
Phosphorus | 0.015 |
Sulfur | 0.01 |
Chromium | 19-21 |
Nickel | 33-37 |
Molybdenum | 9-10.50 |
Cobalt | Balance |
Titanium | 0.01 |
Iron | 1 |
Boron | 0.015 |
FWM chemistry is for reference only, and is not to be used for specification purposes.
English | Metric | |
---|---|---|
Density | 0.304 lbs/in3 | 8.41 g/cc |
Modulus Of Elasticity | 33.8x106psi | 233 Gpa |
Electrical Resistivity | 40.7µohm-in | 1033 µohm-mm |
Thermal Conductivity | 77.7 Btu-in/hr-ft2-°F | 11.2 W/mK |
Thermal Coefficient of Expansion | 7.11 µin/in-°F | 12.8 µm/m-°C |
A reducing atmosphere is preferred for thermal treatment but inert gas can be used. 35N LT will fully anneal at 1010-1177°C in just a few minutes. For optimum mechanical properties, cold worked 35N LT should be aged at 538-593°C for four hours.
35N LT is an excellent combination of strength and corrosion resistance. Typically used in the cold-worked condition, tensile strengths are typically comparable to 304. End uses in the medical field are: pacing leads, stylets, catheters and orthopaedic cables.
%CW | Y.S. | U.T.S. | % Elongation | ||
---|---|---|---|---|---|
ksi | MPa | ksi | MPa | ||
0% | 130 | 896 | 190 | 1310 | 40.00% |
20% | 190 | 1310 | 240 | 1655 | 8.00% |
37% | 240 | 1655 | 280 | 1931 | 3.80% |
50% | 270 | 1862 | 300 | 2268 | 3.80% |
60% | 290 | 1999 | 320 | 2206 | 3.50% |
68% | 300 | 2068 | 330 | 2275 | 3.50% |
75% | 305 | 2103 | 340 | 2344 | 3.30% |
80% | 315 | 2172 | 350 | 2413 | 3.00% |
84% | 325 | 2241 | 360 | 2482 | 3.00% |
90% | 333 | 2296 | 370 | 2551 | 3.00% |
93% | 338 | 2330 | 376 | 2586 | 2.50% |
95% | 340 | 2344 | 380 | 2620 | 2.50% |
Values are typical for diameters smaller than 0.010 in (0.254 mm). All data represents results from a 10 in (25.4 cm) test gauge length.
Cobalt based alloys develop a highly polished appearance as they are drawn to fine diameters. Surface roughness can be less than 5 RMS when processed using single crystal natural diamond dies and measured with a profilometer. Diameters over 0.040" are finished with polycrystalline dies and exhibit a rougher surface than natural diamond dies. Diameters over 0.100" will have an even rougher surface because they are drawn with carbide dies. Additional finish treatments can enhance the surface of the wire.