Apple Inc.
Steel compositions and solution nitriding of stainless steel thereof

Abstract:

The disclosure provides methods of making iron-based alloys, as well as resulting alloys. An iron-based alloy containing a small amount of nickel (e.g., 0.5 to 2.0 wt %) is annealed and machined. The alloy is sufficiently ductile to reduce the likelihood of cracking, while not sufficiently high to result in a hardened alloy. After the alloy is shaped, the alloy is hardened by nitriding.