ASTM B693-17(2022)

ABSTRACT This specification covers electrical contact components made from silver-nickel by powder metallurgical procedures. This covers compositions within the silver-nickel system normally specified by users of electrical contacts. Chemical analysis shall be performed to evaluate material conformance to specified composition requirements. A representative sample of chips may be obtained by milling, drilling, or crushing with dry tools, (without lubrication). In order to obtain free chips, the parts selected for testing shall have the oil extracted, if necessary. Physical tests including microstructure shall be performed on a representative number of specimens. SIGNIFICANCE AND USE 9.1 Proprietary methods for manufacture of these materials vary significantly among suppliers and these methods influence such properties as arc erosion, contact resistance, and the tendency to weld in service. Since the performance of contacts in a device depends on numerous factors outside the contact itself (opening speed, closing speed, contact pressure, contact bounce, environmental variations, assembly technique and variations, etc.), this specification cannot ensure performance control in the application. As part of the qualification on initial samples, it is recommended that the user functionally test the materials electrically for all devices applicable to the material's use. This specification provides a means for the contact manufacturer and contact user to reach agreement on the details of material to be supplied for a specific use and reasonable assurance that future lots will be similar in properties and microstructure to the initial test or sample contact supplied. SCOPE 1.1 This specification covers electrical contact components made from silver nickel by powder metallurgical procedures. 1.2 This specification covers compositions within the silver-nickel system normally specified by users of electrical contacts. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 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 become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use. 1.5 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.