AISI 4142H Alloy Steel (UNS H41420)

Topics Covered

Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations


Steel is a metal alloy chiefly consisting of iron in addition to small amounts of carbon based on the grade and quality of the steel. Alloy steel is a type of steel to which one or more elements besides carbon have been added to form a desired mechanical property.

AISI 4142H is a chromium-molybdenum steel whose mechanical properties and toughness can be improved after heat treatment. The following section will discuss in detail about AISI 4142H alloy steel.

Chemical Composition

The chemical composition AISI 4142H alloy steels is outlined in the following table.

Element Content (%)
Iron, Fe 96.615 - 97.91
Chromium, Cr 0.75 - 1.2
Manganese, Mn 0.65 - 1.1
Carbon, C 0.39 - 0.46
Silicon, Si 0.15 - 0.30
Molybdenum, Mo 0.15 - 0.25
Sulfur, S ≤ 0.040
Phosphorous, P ≤ 0.035

Physical Properties

The following table shows the physical properties of AISI 4142H alloy steels.

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

Mechanical Properties

The mechanical properties of AISI 4142H alloy steels are displayed in the following table.

Properties Metric Imperial
Modulus of elasticity 205 GPa 29700 ksi
Bulk modulus 140 Gpa 20300 ksi
Shear modulus 80 Gpa 11600 ksi
Poisson’s ratio 0.29 0.29
Hardness, Brinell 187 - 229 187 - 229
Hardness, Vickers 218 218
Hardness, Knoop 230 230
Hardness, Rockwell C 15 15
Hardness, Rockwell B 94 94
Machinability 65 65

Thermal Properties

The thermal properties of AISI 4142H alloy steels are given in the following table

Properties Metric Imperial
Thermal conductivity 42.6 W/mK 296².°F

Other Designations

Other designations that are equivalent to AISI 4142H alloy steels include the following.

  • DIN 1.7223
  • UNI 38 CrMo 4
  • ASTM A304
  • SAE J1268


The following are the list of applications of AISI 4142H alloy steels:

  • Break and bending dies
  • Die holders
  • Flanges
  • Collets
  • Spindles, axles, clutch parts
  • Forming rolls
  • Machine tool components
  • Wrenches and other hand tools

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