AISI 4142 Alloy Steel (UNS G41420)

Topics Covered

Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations


Alloy steels comprise a spectrum of steels whose compositions include the elements Ni, Si, Va, C, Mo, Cr, Mn, and B which have been fixed for carbon steels. These steels are more responsive to mechanical and heat treatments than carbon steels.

The following datasheet will provide more details about AISI 4142 alloy steel.

Chemical Composition

The following table shows the chemical composition of AISI 4142 alloy steel.

Element Content (%)
Iron, Fe ≥ 96.725
Chromium, Cr 0.80-1.10
Manganese, Mn 0.75-1.10
Carbon, C 0.40-0.45
Silicon, Si 0.15-0.30
Molybdenum, Mo 0.15-0.25
Sulfur, S ≤ 0.040
Phosphorous, P ≤ 0.035

Physical Properties

The physical properties of AISI 4142 alloy steel are outlined in the following table.

Properties Metric Imperial
Density 7.85 g/cm3 0.284 lb/in³

Mechanical Properties

The mechanical properties of AISI 4142 alloy steel are highlighted below.

Properties Metric Imperial
Elastic modulus 190-210 GPa 27557-30458 ksi
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Hardness, Brinell (annealed and cold drawn) 187-229 187-229
Hardness, Knoop (converted from Brinell hardness) 230 230
Hardness, Rockwell B (converted from Brinell hardness) 94 94
Hardness, Rockwell C (converted from Brinell hardness, value below normal HRC range, for comparison purposes only) 15 15
Hardness, Vickers (converted from Brinell hardness) 218 218
Machinability (annealed and cold drawn, based AISI 1212 steel, as on 100 machinability) 65 65

Thermal Properties

The thermal properties of AISI 4142 alloy steel are outlined below.

Properties Metric Imperial
Thermal conductivity 42.6 W/mK 296 BTU in/hr.ft².°F

Other Designations

Equivalent materials to AISI 4142 alloy steel are:

  • ASTM A322
  • ASTM A331
  • ASTM A505
  • ASTM A519
  • ASTM A547
  • SAE J404
  • SAE J412
  • SAE J770
  • ASTM A29
  • ASTM A372 (VIII)
  • ASTM A711
  • ASTM A752
  • ASTM A829
  • SAE J1397


  1. Sisira Weerasekaralage Sisira Weerasekaralage Sri Lanka says:

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