This superalloy is initially melted using Vacuum Induction Melting (VIM) techniques. This is followed by an Electro Slag Remelt (ESR) to remove some impurities. This practice may be followed by Vacuum Arc Remelting (VAR). The triple-melt practice is thought to give best overall performance for this alloy.
ASTM F562 | |
---|---|
Carbon | 0.025 |
Manganese | 0.15 |
Silicon | 0.15 |
Phosphorus | 0.015 |
Sulfur | 0.01 |
Chromium | 19-21 |
Nickel | 33-37 |
Molybdenum | 9-10.5 |
Cobalt | Balance |
Titanium | 1 |
Iron | 1 |
Boron | 0.015 |
Density | 0.304 lbs/in3 |
---|---|
Modulus Of Elasticity | 33.76-34.05 psi x 106 |
Electrical Resistivity | 1033 µohms-mm |
Thermal Conductivity | 11.2 W/mK (100°C) |
A reducing atmosphere is preferred for thermal treatment but inert gas can be used. MP35N will fully anneal at 1010-1177°C in just a few minutes. For optimum mechanical properties, cold worked MP35N should be aged at 538-593°C for four hours.
MP35N 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 | U.T.S. (psi) | % Elongation (10" gauge length) |
---|---|---|
0% | 152,000 | 50% |
20% | 201,000 | 7% |
37% | 253,000 | 3% |
50% | 285,000 | 2.5% |
60% | 303,000 | 3.2% |
68% | 319,000 | 3.0% |
75% | 329,000 | 3.1% |
80% | 332,000 | 3.3% |
84% | 339,000 | 3.2% |
90% | 345,000 | 3.4% |
93% | 346,000 | 2.2% |
95% | 362.000 | 2.8% |
Values are typical and may not represent all diameters. Test method will affect results.
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 SCND* dies and measured with a profilometer.
Diameters over 0.040" will not have as smooth a finish because of polycrystaline 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.
*SCND means single crystal natural diamond.