This specification covers magnesium alloy permanent mold casting. The castings may be subjected to the heat treatment necessary to produce material that will conform to the requirements specified. Heat treatment shall be performed on the whole of a casting, never on a part only, and shall be applied in a manner that will produce the utmost uniformity. The castings shall be of uniform quality and condition, free of cracks or other injurious defects, and shall be well cleaned by sand blasting or any other approved process before inspection. The material shall conform to the chemical composition limits prescribed. Any suitable method of chemical analysis may be used. Unless otherwise specified, heat treatment for the applicable tempers designated shall be in accordance with practice B 661 or with Military Specification MIL-M-6857. The tension test specimens representing the castings shall conform to the requirements specified. At least one tension test specimen shall be cast from each melt of 2000 lb (907 kg) or fraction thereof to represent the castings poured from the same melt. The tension tests shall be made in accordance with test methods B 557.