Purpose This specification covers the engineering requirements for heat treatment of magnesium alloy castings and for parts machined from castings. Application This specification is applicable to castings of the following magnesium alloys: AM100A AZ63A AZ81A AZ91C AZ91E AZ92A EQ21A EV31A EZ33A QE22A ZE41A WE43A WE43B WE54A ZK51A ZK61A When AMS 2768 is specified and specific heat treat processing instructions are included in the material specification@ the equipment and control requirements of AMS 2768 shall apply. For alloys not specifically covered@ the applicable provisions of this specification shall be invoked but temperatures@ times@ and quench procedures shall be as specified by the purchaser. It is permissible@ for specific parts@ to use equipment@ practices and test methods which conformed to AMS-H-6857 or MIL-H-6857 and were previously acceptable to the purchaser.