This alloy is a general purpose heat treatable chromium steel which is a popular cutlery grade.
Dental and surgical instruments, cutlery, pump shafts, plastic molds and dies, steel balls, and various hand tools.
Similar to machining some of the high carbon tool steel, this alloy has tough, stringy chip build-up.
Not commonly welded due to its air hardening characteristics. Welding may be performed after preheating to 300-400 F (149-204 C) with post weld tempering at temperature for 2 hours . Filler metal should be AWS E/ER420.
Bring temperatures slowly up to 1400 F (760 C), then on to 2000-2200 F (1097-1204 C), after working, furnace cool slowly to avoid cracking. Reheat often to keep the working temperature above 1600 F.
420 will withstand only minor cold work. Radical forming operations will result in cracking.
Soak at 1850-1950 F (1010-1066 C) at quench in heated oil.