CON-SERV offers a variety of alloys which are approved for nuclear, structural, industrial and bridge applications.
These bronzes are lubricated to approximately 25% of the bearing surface. The standard lubricant takes temperatures to 250°F.
Lube 1 has a temperature range from 200°F to 500°F. Lube 2 has a temperature range from 500°F to 800°F. For nuclear applications (normal containment, atmosphere including borated water spray, and radiation below 2.2 x 106 rads.). Use Lube AE for all temperatures to 800°F. Slots and holes if required shall be fabricated in the bearing manufacturer's plant.
Designers use 15% friction factor as a practical figure and increase this for high temperature applications (greater than 500°F.) Any mating steel surfaces should be finished to a 63 to 125 RMS.
Bronze bearings are cast, machined and lubricated. Edges should be specified "as-cast" or machined.
For alloy C90500 Modified, the maximum design pressure is 800 psi at 600°F. For alloy C86300, the maximum design pressure is 1000 psi at 800°F. A straight line interpolation is appropriate between the 250°F design pressure and the maximum use temperature pressure.
Generally used for temperatures from 500°F to 1000°F
This material is a form of gray cast iron which is produced utilizing flake graphite. For Meehanite sliding against a ground steel plate (63 to 125 RMS) a design friction factor of 15% is appropriate.
Grade Type GA50 (50,000 Tensile Strength) is usually specified for bearing applications.
Wear is negligible when sliding against itself. Graphite may be purchased bonded to steel back-up plates or structural shapes as the job may require. Bonding epoxy is available.The maximum temperature limit on the epoxy is 300°F. Hi-temperature applications require mechanical attachment of the graphite.
Unbonded flats are typically 1/2" thick. Bonded 1/4" graphite to 1/4" steel is specified as 25CG 25CS 50L. Typically the steel plate is 1" larger in both width and length than the graphite for field welding.
Standard Design Criteria:
- Comprehensive Strength: 2000 psi
- Coefficient of friction: Static 0.15
- Maximum Service Temperature: 750° F on graphite
This bearing system enables the designer to enjoy the low friction of PTFE at a bearing point temperature above the use limit (500°F) of PTFE.
These bearings provide a coefficient of friction less than 3% at a design pressure of 2500 psi (max.) with little variation at lesser pressures.
The bearings can be installed with a stitch weld 1/2 inch long 3 inch on center on all sides. The upper and lower units must be backed up with structural plates so that a uniform load is transmitted into the unit. Bending of the units is unacceptable.