1.1 This specification covers austenitic ductile iron, Type D-2M, Classes 1 and 2, for compressors, expanders, pumps, valves, and other pressure-containing parts intended primarily for low-temperature service. 1.2 The This specification covers austenitic ductile iron castings for compressors, expanders, pumps, valves, and other pressure-containing parts intended primarily for low-temperature service. The castings covered here are Type D-2M, Class 1, Class 2, Class 3