Designation by Standards
Chemical Composition (in weight %)
|0.46||max. 1.0||max. 1.0||13.50||-||-||-||-||-|
Steel 420 displays the best corrosion resistance in hardened condition with a surface polished to give a mirror finisih.
All kinds of cutting tools - knives, shears, surgical instruments, moulds for plastics production, as well as for surgical instruments and measuring gauges.
Physical properties (avarage values) at ambient temperature
Modulus of elasticity [103 x N/mm2]: 220
Density [g/cm3]: 7.73
Thermal conductivity [W/m.K]: 30.0
Electric resistivity [Ohm mm2/m]: 0.65
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 730-780oC, cool slowly in furnace or air. Structure is ferrite with spherical carbides.
Harden from a temperature of 980-1030oC followed by oilor air quenching. Hardness after quenching is 56 HRC.
Tempering temperature: 100-200oC.
Tempering Temperature (oC) vs. Hardness (HRC)
Hot forming temperature: 1100-800oC.
Similar to machining some of the high carbon tool steel, this alloy has tough, stringy chip build-up.
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.
Note: The hot forming temperature stated should not be exceeed, as harmful grain coarsening and simultaneous formation of a carbide network along the grain boundaries will otherwise occur. This results in poor developmnet of hardness and a decline in toughness and elasticity in hardened condition.
All technical information is for reference only.