[2] 17-4 stainless steel can be heat treated to approximately 44 Rc,[1] and an ultimate tensile strength of 1,300 MPa (190,000 psi).
[3] The corrosion resistance[1] and machinability[4] of 17-4 are comparable to austenitic 304 stainless steel.
Overaging (aging beyond the peak strength condition) improves resistance to stress corrosion cracking.
[5] 17-4PH is used in applications requiring high strength, hardness, and corrosion resistance up to 300 °C (600 °F).
[4] It is commonly used in the aerospace industry for its high strength, and in marine applications for its corrosion resistance, although it can be susceptible to crevice corrosion in stagnant salt water.