Havar® is a heat treatable Cobalt base alloy that provides very high strength. The alloy has excellent corrosion resistance and is non-magnetic. Applications have included pressure diaphragms, power springs, gap spacers in magnetic heads, and target foils in nuclear physics.
Forming cold rolled Havar requires large radius (90° Bend – 8 X thickness) prior to age hardening. The joining can be accomplished using both welding and soldering techniques.The ultimate endurance life is achieved by heat treating the alloy at 1000°F after 80% cold work. The alloy will retain 75% of room temperature strength up to 950°F (Figure 1).
Available Sizes:
Havar® is available from Hamilton Precision Metals as strip product in thicknesses from 0.0005” to 0.025” (0.0127 mm to 0.635 mm) and widths to 7.5” (190.5 mm). A foil product is available in thicknesses down to 0.000060” and widths of 4.0” (101.6 mm). The material corresponds to UNS R30004.
Nominal Composition
| HAVAR® NOMINAL COMPOSITION |
| Cobalt |
42.0%
|
| Chromium |
19.5%
|
| Nickel |
12.7%
|
| Tungsten |
2.7%
|
| Molybdenum |
2.2%
|
| Manganese |
1.6%
|
| Carbon |
0.2%
|
| Iron |
Balance
|
Mechanical Properties
| HAVAR® MECHANICAL PROPERTIES |
|
|
ANNEALED |
COLD ROLLED
|
COLD ROLLED
HEAT TREATED
|
| Ultimate Tensile Strength |
140,000 PSI |
270,000 PSI |
330,000 PSI
|
| Yield Strength (0.2% Offset) |
70,000 PSI
|
250,000 PSI |
300,000 PSI |
| Elongation in 2” * |
40% |
1% |
1%
|
| Hardness |
RC 25
|
RC50 |
RC60 |
| Modulus of Elasticity (Tension) |
29.5 x 106
PSI
|
- |
- |
*The measured elongation will be less as thickness decreases to 0.002” and less.
These values may be adjusted by control of process variables – consult HPM for desired values.
Physical Properties
| HAVAR® PHYSICAL PROPERTIES |
|
Density
|
0.300 lbs/cu.in.
|
| Melting Point (Approx.) |
1480°C |
| Electrical Resistivity @ R.T. |
92 Microhm·cm |
| Thermal Expansion Coefficient (0° to 50°C) |
12.5 x 10-6/°C
|
| Thermal Conductivity |
13.0 W/m·K
|
| Magnetic Attraction |
None
|
Typical values to guide alloy selection but are not a guarantee of minimum or maximum.