Designation by Standards
Chemical Composition (in weight %)
This alloy is a general purpose heat treatable chromium steel which is a popular cutlery grade. Martensitic stainless steel.
Dental and surgical instruments, cutlery, pump shafts, plastic molds and dies, steel balls, and various hand tools, pump components, shafts, turbine blades, pressing dies for tablets, glass and plastics processing tools.
Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 216
Density [g/cm3]: 7.73
Thermal conductivity [W/m.K]: 30.0
Electric resistivity [Ohm mm2/m]: 0.60
Specific heat capacity[J/g.K]: 0.46
Coefficient of Linear Thermal Expansion 10-6 oC-1
Modulus of Elasticity [103 N/mm2]
Heat to 730-810oC, air cooling. Structure is ferrite with spherical carbides.
Harden from a temperature of 950-1050oC followed by oil, air quenching.
Tempering temperature: 650-750oC. Transformation structure with ferrite.
Mechanical Properties at Room Temperature
|Size range mm||Heat treatment condition||0.2 % proof stress (N/mm2)||Tensile strength (N/mm2)||Elongation (%)||Notch impact energy (ISO-V) (J)||Hardness HB max.|
0.2 % Proof Stress (N/mm2) at Elevated Temperatures
Hot forming temperature: 1100-850oC.
Similar to machining some of the high carbon tool steel, this alloy has tough, stringy chip build-up.
Embittlemnt: It must be in mind that the temperature range between 425 and 525oC must be avoided owing to embritllement at 475oC.
420 is resistant to the atmosphere, fresh water, dilute acids and alkalis and fruit and vegetable juices.
Not commonly welded due to its air hardening characteristics. Welding may be performed after preheating to 149-204oC with post weld tempering at temperature for 2 hours. Filler metal should be AWS E/ER420.
All technical information is for reference only.