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, and Class 4. The castings shall be made in the electric-arc furnace, induction furnace, cupola, or any other furnace which is capable of producing castings. Heat and product analyses shall be performed wherein specimens shall conform to required chemical composition of carbon, silicon, manganese, nickel, chromium, and phosphorus. The castings shall undergo tension tests and impact tests, and shall conform to the following mechanical requirements: tensile strength, yield strength, elongation, Brinell hardness, and Charpy V-notch.

1.1 This specification2 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 These grades of austenitic ductile iron are characterized by having their graphite substantially in a spheroidal form and free of flake graphite. They are essentially free of carbides and contain sufficient alloy content to produce a stable austenitic matrix down to −423°F [−252°C] (liquid hydrogen).

1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.3.1 Within the text, the SI units are shown in brackets.

1.4 The following precautionary caveat pertains only to the test methods portion, Section 11, of this specification: 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 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.