Silicon Nitride Rollers
High speed machine tool spindles and the high pressure liquid hydrogen turbopumps that move liquid hydrogen in the space shuttle are just two examples of the uses for hybrid roller bearings.
Subcommittee F34.01 on Rolling Element has now developed a standard for hybrid roller bearings. The recently approved F2730/F2730M, Specification for Silicon Nitride Cylindrical Bearing Rollers, is under the jurisdiction of Subcommittee F34.01, part of Committee F34 on Rolling Element Bearings.
According to William Mandler, general manager, ENCERATEC Inc., F2730/F2730M complements another ASTM standard, F2094/F2094M, Specification for Silicon Nitride Bearing Balls. Mandler said that increasing use of silicon nitride rollers in recent years led to the development of F2094/F2094M.
F2730/F2730M will be used by end users of bearings, bearing manufacturers and roller manufacturers. “ASTM F2730, like ASTM F2094, provides a specification for the material used to make the roller — three levels of capability are included so the material can be specified for the severity of the intended application,” says Mandler. “The specification also provides dimensional specifications for form and surface condition of the finished roller.”
End users will be able to apply the new standard to the procurement of finished bearings so that they are made with rollers of sufficient material capability for the intended application. Bearing companies will be able to use F2730/F2730M in procuring finished silicon nitride rollers from roller manufacturers while the manufacturers will use the standard to obtain unfinished roller blanks to meet the required levels of material capability.
Mandler says that Subcommittee F34.01 is always looking for interested parties to participate and offer comments on proposed or existing standards, and he notes that some of the activities in which the subcommittee is currently engaged are the development of specifications for titanium carbide coated stainless steel balls and defect criteria for bearing balls.
Technical Information: William Mandler, ENCERATEC Inc., Columbus, Ind.
ASTM Staff: Joseph Hugo