Over deze norm
1.1 This specification is intended to be a means of calling out finished machined parts ready for commercial use.
1.2 This specification establishes requirements for parts machined from unplasticized, 100 % polychlorotrifluoroethylene (PCTFE) homopolymers.
1.3 This specification does not cover parts machined from PCTFE copolymers, PCTFE film or tape less than 0.25-mm [0.010-in.] thick, or modified PCTFE (containing pigments or plasticizers).
1.4 This specification allows for parts containing regrind and recycled material.
1.5 The specification does not cover PCTFE parts used in aerospace applications involving storage and handling of oxygen media, air media, inert media, and certain reactive media (specifically ammonia, gaseous hydrogen, and liquid hydrogen), in which dimensional stability, high molecular weight, molecular weight retention, and crystallinity control are important considerations. For aerospace grade, machined PCTFE parts, use Specification D 7194.
1.6 ApplicationPCTFE parts covered by this specification are made of 100 % PCTFE resin, free of plasticizers, fillers, or other additives. The parts meet specific physical characteristics appropriate for their end use, and are typically used in applications requiring good electrical properties or resistance to aggressive chemical media. General purpose PCTFE parts include seals, gaskets, valve and pump parts (cryogenic and noncryogenic), translucent tubing, sight glasses, flowmeter tubes, heavy-walled solid pipes and fittings, gears, cams, bearings, laboratory ware, circuit boards, electrical connector covers and switches, radome covers, and a variety of other stock shapes. They are removed and replaced during normal maintenance procedures. The parts also experience static or dynamic mechanical loading, and temperatures ranging from cryogenic to temperatures at or above the glass transition temperature, T
Quick-quenched PCTFE will potentially exhibit dimensional relaxation in the vicinity of T
Although no recommendations are made regarding the limiting upper use temperature of PCTFE, the heat deflection temperature of PCTFE as determined by Test Method D 648 is 126C [259F].
1.7 The values stated in SI units are to be regarded as standard. The values in brackets are for information only.
There is no equivalent ISO standard.
|Engelse titel||Standard Specification for Parts Machined from Polychlorotrifluoroethylene (PCTFE) and Intended for General Use|