Carbon & alloy steel · EN 10083-3

25CrMo4

Full datasheet

Overview

25CrMo4 is a carbon/alloy engineering steel (EN 10083-3) for shafts, gears, and heat-treated machine parts.

Typical supply: Bars, forgings, plate, tube

Mechanical Properties

Young's modulus E210 GPa
Shear modulus G80.8 GPa
Yield / proof Re600 MPa
Ultimate Rm800 MPa
Poisson's ratio ν0.3

Thermal Properties

Thermal expansion α12 µm/(m·K)

For temperature derating, open Temperature Properties.

Physical Properties

Density ρ8e+3 kg/m³
Specific strength Sy/ρ7.64e+4 Pa·m³/kg
Specific stiffness E/ρ2.68e+7 Pa·m³/kg

Typical supply: Bars, forgings, plate, tube

Density typically ~7800–7850 kg/m³. Bar and forging forms dominate machine design.

Applications

  • Shafts and axles
  • Machine components under fatigue
  • Gears and pinions (with heat treatment)
  • High-strength fasteners and couplings

Advantages

  • Higher strength and hardenability than mild structural steel
  • Responds well to quench and temper for tailored properties
  • Good fatigue performance when heat-treated correctly

Limitations

  • Often needs heat treatment to reach published strengths
  • Weldability may require preheat / post-weld heat treatment
  • Corrosion resistance similar to carbon steel unless coated

Standards

  • EN 10083-3

Equivalent Materials

Compare with these grades →

Electrical Properties

Not published for this grade.

Chemical Composition

Not published for this grade.

Machinability

Machinability index: 55 (AISI 1212 ≈ 100)

Machinability depends on condition; annealed stock machines more easily than QT.

Cost

Relative cost band: moderate

Low-to-moderate premium over mild steel depending on alloy content.

Corrosion

Class: fair

Protect like carbon steel; oil, plating, or paint for service parts.

  • Oil-lubricated machineryfair
  • Outdoor uncoatedpoor

For allowance / life screening, open Corrosion Allowance.