17-4 stainless steel for 17-4 include components which require high hardness and/or corrosion resistance at temperatures of up to . Specific applications for 17-4 include the petroleum and chemical industries, as well as use in aircraft parts. 17-4 stainless steel SAE type 630 stainless steel (more commonly known as 17-4; also known as UNS 17400) is a grade of martensitic precipitation-hardened stainless steel. It contains approximately 15–17.5% (17) chromium and 3–5% (4) nickel, as well as 3–5% copper. 17-4 can be heat treated to high levels of strength and hardness, and features corrosion resistance and machinability comparable to austenitic 304 stainless. Being martensitic,
The Stainless Steel Rat name is not revealed to the reader. The Kekkonshiki, also known as "The Gray Men", are a human culture who initially prefer domination to coexistence. Their expertise lies in using technology to manipulate sentient minds, and they have manipulated both humans and aliens on a grand scale. Jim has experienced one of their techniques (in which a gray man agent seemingly severs his hands with an axe; this was an illusion). Jim has knowingly opposed them on two separate occasions ("The Stainless Steel Rat's Revenge" & "The Stainless Steel Rat Wants You") however during conversation it is revealed by Kome