42CrM04 alloy steel

Introduction

We manufacture forging ingots, billets, and blooms  in alloy steel specifically for 42CrM04, designed for high-strength and heavy-duty engineering applications.

42CrM04 is a medium carbon chromium-molybdenum alloy steelrenowned for its exceptional strength, high toughness, and excellent fatigue resistance. It is engineered to withstand high mechanical loads, shock, and repeated stress, making it an ideal choice for automotive, heavy machinery, and critical engineering components.

The addition of chromium enhances hardenability and wear resistance, while molybdenum improves toughness, tempering resistance, and high-temperature performance. 42CrM04 also offers good machinability in the annealed condition and maintains dimensional stability after heat treatment, making it highly suitable for forging and precision machining applications.

This grade provides an excellent balance of performance, durability, and cost-effectiveness  for demanding industrial uses.

Chemical composition

Element Content (%) Function / effect
Carbon (c) 0.38 – 0.45 Provides hardness and tensile strength
Manganese (mn) 0.50 – 0.80 Improves hardenability and toughness
Silicon (si) Max 0.40 Increases strength and elasticity
Chromium (cr) 0.90 – 1.20 Enhances hardness, wear resistance, and depth of hardening
Molybdenum (mo) 0.15 – 0.30 Improves toughness, fatigue resistance, and tempering stability
Phosphorus (p) Max 0.035 Impurity; lower content improves toughness
Sulphur (s) Max 0.030 Impurity; controlled for better machinability

Mechanical properties (typical – quenched & tempered)

  • Tensile strength: 850 – 1100 MPa
  • Yield strength: 650 – 900 MPa
  • Hardness: 28 – 36 HRC (customizable)
  • Impact toughness: High
  • Fatigue resistance: Excellent

(properties may vary depending on section size and heat treatment  conditions)

Heat treatment

  • annealing: used to soften the steel and improve machinability prior to final processing.
  • quenching: heating to approximately 830 – 870°c followed by rapid cooling to obtain a hard martensitic structure.
  • tempering: reheating to a controlled temperature to relieve internal stresses and improve toughness while maintaining required hardness.

The heat treatment  process can be optimized to achieve the desired balance of strength and toughness based on specific application requirements.

Key features and benefits

  • through hardening capability for uniform properties
  • high strength and excellent toughness
  • superior fatigue and wear resistance
  • good machinability in annealed condition
  • dimensional stability after heat treatment
  • highly suitable for forging and machining applications

Typical applications

  • crankshafts and camshafts
  • gears and pinions in transmission systems
  • axles, shafts, and spindles
  • connecting rods and engine components
  • forged parts for automotive and heavy-duty machinery
  • other high-stress components requiring strength and toughness

Equivalent steel grades

  • 42CrM04 has several international equivalents, including:
  • En19 (bs en 10083-3)  – european standard
  • AISI  4140  – american standard
  • is 1570 (part 3) – 4140 type  – indian standard

Why choose 42CrM04 for your application?

42CrM04 offers a superior combination of high strength, toughness, and fatigue resistance . Its excellent hardenability and stable response to heat treatment  make it ideal for components subjected to heavy loads and cyclic stress. Additionally, its good machinability and dimensional stability help reduce manufacturing costs and improve final product quality.

Comparison table for similar grades

Grade Carbon (%) Key applications Heat treatment Comments
42CrM04 0.38 – 0.45 Shafts, gears, crankshafts Quenching & tempering High strength and fatigue resistance
En19 0.35 – 0.45 General engineering components Quenching & tempering Widely used equivalent
Aisi 4140 0.38 – 0.43 Automotive and machinery parts Quenching & tempering Common american equivalent

Summary

42CrM04 is a high-performance chromium-molybdenum alloy steel optimized for quench and temper applications  in automotive and engineering industries. It delivers reliable performance, long service life, and excellent value for a wide range of high-stress components.