AISI 420


AISI 420 is the most common grade of martensitic steel. This tempered steel presents the completely complementary characteristics of the most used ferritic and austenitic steel.

The tempering process to which it is subjected makes it very useful for cutlery, surgical and dental instruments, springs, molds for plastics, spheres, wear resistant components, pump components, parts in control devices, diesel engine pumps. In tempered and annealed state with mirror-polished surfaces it has good resistance to corrosion in highly aggressive, non-chlorinated environments.

Mechanical Properties Test Method As Built Heat Treated
Tensile strength ISO 6892-1:2009(B) Annex D 1050 ± 25 MPa 1520 ± 30 MPa
Yield Strength (Rp 0.2%) ISO 6892-1:2009(B) Annex D 700 ± 15 MPa 950 ± 20 MPa
Elongation at Break ISO 6892-1:2009(B) Annex D 2.5 ± 0.2% 6.3 ± 0.2%
Young’s modulus - 190 ± 7 GPa 195 ± 5 GPa
Hardness - Rockwell - 55 ± 1 HRC 53 ± 1 HRC
Thermal Properties Test Method As Built Heat Treated
Thermal conductivity ASTM E1461-13 30 W/m°C -
Specific heat capacity ASTM E1461-13 460 J/kg°C -
Chemical Composition and Physical Properties    
Chemical composition C
Mn
Si
Cr
Ni
P
S
0.16 - 0.25%
1.5%
1%
12-14%
0.1%
0.04%
0.03%
Physical Properties Relative density Approx. 99,99 %
  Density 7.70 g/cm3
Heat Treatment Temperature Time (h) Atmosphere
Stress Relief RT - 315°C 2 Inert
  315°C 2 Inert
  315°C - RT - Inert