Precision Alloy 4J42/4J48/4J52 The application of Precision Alloy 4J42/4J48/4J52 : It is applied to soft glass-to-metal and ceramic-to-metal seals in electronic component. *Alloy 42,ASTM F30,UNS k94100,(Fe-42Ni),Chinese 4J42 *Alloy 52,ASTM F30,UNS K95050,