46 CFR §56.60-15

1. (a)Ductile cast iron components made of material conforming to ASTM F1155 (incorporated by reference, see § 56.01-2) may be used within the service restrictions and pressure-temperature limitations of UCD-3 of Section VIII of the ASME BPVC (incorporated by reference; see § 56.01-2).
2. (b)Ductile iron castings conforming to ASTM F1155 may be used in hydraulic systems at pressures in excess of 7500 kPa (1000 psi) gage, provided the following:
   1. (1)The castings receive a ferritizing anneal when the as-cast thickness does not exceed 1 inch;
   2. (2)Large castings for components, such as hydraulic cylinders, are examined as specified for a casting quality factor of 90 percent in accordance with UG-24 of Section VIII of the ASME BPVC; and
   3. (3)The castings are not welded, brazed, plugged, or otherwise repaired.
3. (c)After machining, ductile iron castings must be hydrostatically tested to twice their maximum allowable working pressure and must show no leaks.
4. (d)Ductile iron castings exhibiting less than 12 percent elongation in 50 millimeters (2 inches) when subjected to a tensile test must meet the requirements for cast iron in this part.