Castings purchased under this specification are intended primarily for use in manufacture and assembly of ordnance equipment which requires small, sound, high quality, and intricate precision castings weighing from approximately 1-ounce to 6 pounds.

Composition numbers IC-302, IC-304, IC-304L, IC-310, IC-316, IC-321, and 1C-347 are austenitic stainless Steels of the chromium nickel type. As a group they are generally more corrosion resistant than ferritic and martensitic stainless steels and have better elevated temperature oxidation resistance and strength. Maximum corrosion resistance for these materials is obtained in the solution heat-treated condition. Selection for design purposes will be governed primarily by the type of corrosive media involved since these alloys exhibit similar mechanical properties and castability.

Composition numbers IC-410, IC-420, IC-431, IC440A, and IC-440C are martensitic stainless steels hardenable by heat treatment. Resistance to corrosion is generally increased by the greater percentages of chromium and decreasing percentages of carbon. Composition IC-410 is intended for structural parts where corrosive conditions are not severe. This alloy is subject to rusting and pitting when exposed to sea water and will rust in salt air. Composition IC-420 will exhibit greater hardness and strength than IC-410 and is used for bearing surfaces, cutlery, gages, valve parts, etc. Composition IC-431 possesses greater corrosion resistance than other steels in this group. Reheating quenched composition IC-431 material in the range 850-1000°F should be avoided to prevent loss of impact strength. Composition numbers IC-440A and IC-440C offer maximum hardness in this group. All alloys in this group possess good casting fluidity. Composition numbers IC-410, IC-440A, and IC-440C tend to form surface pits when cast and may require finishing operations.

Composition number IC-322A is a precipitation hardening stainless steel which can be heat-treated to high strength and with corrosion resistance superior to the IC-400 series.