ASTM F 138

This specification covers the requirements for wrought 18chromium-14nickel-2.5molybdenum stainless steel bar and wire used for the manufacture of surgical implants. Bar and wire shall be furnished, as specified, in the hot-worked, annealed, cold -worked, or extra hard condition. Fine wire shall be furnished, as specified, in the cold-drawn condition. Types of finish available for bar and wire products are cold-drawn, pickled, ground, and ground and polished. On the other hand, types of finish available for fine wire products are cold-drawn, ground, and ground and polished. The heat analysis shall conform to the requirements as to chemical composition specified and the material shall contain no delta ferrite, chi, or sigma phases when it is examined by metallography. Different tests shall be performed in order to determine the following mechanical properties of the wire and bar: ultimate tensile strength, yield strength, elongation, and Brinell hardness.