AMS 5643 & S17400 & 17-4PH Martensitic Steel
AMS 5643 is used for components such as fasteners, couplings, screws, bushings, studs, fittings, valve stems, roller, wear rings. AMS 5643 Aircraft Quality, it is A Precipitation Hardening Martensitic Stainless steel with an addition of Nb/Cu elements. S17400 Combines High Strength, hardness (up to HRC40), and corrosion resistance.