【国外标准】 Standard Specification for Parts Machined from Polychlorotrifluoroethylene (PCTFE) and Intended for General Use

This specification establishes the requirements for finished parts machined from unplasticized polychlorotrifluoroethylene (PCTFE) homopolymers containing regrind and recycled polymer intended for general commercial use. This specification does not cover parts machined from PCTFE copolymers, PCTFE films or tapes, or modified PCTFE containing pigments or plasticizers. Nor does it 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), wherein dimensional stability, high molecular weight, molecular weight retention, and crystallinity control are important considerations. Materials shall be tested on and conform accordingly to the following properties: specific gravity; melting point; deformation under load; zero strength time (ZST); annealing performance; and dimensional stability.1.1 This specification is intended to be a means of calling out finished machined parts ready for general use.1.2 This specification establishes requirements for parts machined from polychlorotrifluoroethylene (PCTFE) semifinished parts.1.3 For aerospace grade, machined PCTFE parts, use Specification D7194.NOTE 1: Quick-quenched PCTFE will potentially exhibit dimensional relaxation in the vicinity of Tg = 55°C (131°F).NOTE 2: Although no recommendations are made regarding the limiting upper use temperature of PCTFE, the heat deflection temperature of PCTFE as determined by Test Method D648 is 126°C (259°F).1.4 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.1.5 The following precautionary caveat pertains only to the test methods portion, Section 11, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 3: There is no known ISO equivalent to this standard.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.