Historical
SAE AMS 5640U-2007 (SAE AMS5640U-2007)
Steel, Corrosion-Resistant, Bars, Wire, and Forgings 18Cr 9.0Ni Free Machining
This specification covers three types of a free-machining, corrosion-resistant steel in the form of bars, wire, forgings, and forging stock. These products have been used typically for parts on which the amount of machining warrants use of a free-machining grade of steel requiring corrosion resistance similar to the 18-8 type of steels but not subjected to temperatures exceeding 700 \mDF (371 \mDC) during fabrication or in service, but usage is not limited to such applications.
Society of Automotive Engineers [sae]