20CrNi6 alloy steel

Introduction

We manufacture forging ingots, billets, and blooms in alloy steel specifically for 20CrNi6, developed for high-performance case hardening applications.

20CrNi6 is a low carbon chromium–nickel alloy steel designed to deliver a hard, wear-resistant surface combined with a tough and ductile core. This unique property combination makes it ideal for components subjected to high surface stress, shock loads, and repeated fatigue conditions.

The presence of chromium improves hardenability and wear resistance, while nickel enhances core toughness and impact strength. 20CrNi6 exhibits excellent machinability in the annealed condition and maintains dimensional stability after heat treatment, making it well suited for forging and precision machining operations.

This grade offers an excellent balance of strength, toughness, and long service life for demanding engineering and automotive applications.

Chemical composition

Element Content (%) Function / effect
Carbon (c) 0.17 – 0.23 Enables case hardening with a tough core
Manganese (mn) 0.40 – 0.70 Improves hardenability and strength
Silicon (si) Max 0.40 Enhances strength and elasticity
Chromium (cr) 1.00 – 1.30 Improves hardenability and wear resistance
Nickel (ni) 1.40 – 1.70 Increases toughness and fatigue resistance
Phosphorus (p) Max 0.035 Controlled impurity; improves toughness
Sulphur (s) Max 0.035 Controlled impurity; aids machinability

Mechanical properties (typical, depending on condition & heat treatment)

  • Core tensile strength: 800 – 1000 MPa
  • Core yield strength: 600 – 750 MPa
  • Case hardness: 58 – 62 HRC
  • Core hardness: 30 – 40 HRC
  • Impact toughness: Very good
  • Fatigue resistance: Excellent

Heat treatment

  • Annealing: applied to soften the steel and improve machinability prior to carburizing.
  • Carburizing: carbon enrichment at elevated temperature to produce a hard, wear-resistant surface layer.
  • Quenching: rapid cooling after carburizing to form a hard martensitic case.
  • Tempering: performed to relieve internal stresses and improve toughness while maintaining surface hardness.

Heat treatment cycles can be optimized to achieve the required case depth and core strength based on application needs.

Key features and benefits

  • Excellent case hardening characteristics
  • Hard, wear-resistant surface with a tough core
  • High fatigue and impact strength
  • Good machinability in annealed condition
  • Dimensional stability after heat treatment
  • Suitable for forging and precision machining

Typical applications

  • Gears and pinions
  • Transmission and gearbox components
  • Shafts subjected to surface wear
  • Automotive drivetrain components
  • Heavy-duty engineering parts requiring case hardening

Equivalent steel grades

20CrNi6 has several close international equivalents, including:

  • En 10084 – 20CrNi6
  • Din 1.6582 (approximate)
  • AISI / SAE 8620 (closest american equivalent)

(exact properties may vary slightly depending on standard and heat treatment condition.)

Why choose 20CrNi6 alloy steel?

20CrNi6 is an excellent choice for components that demand high surface hardness combined with a tough, shock-resistant core. Its superior fatigue resistance, reliable performance after case hardening, and ease of machining help reduce manufacturing costs while ensuring long service life.

Comparison table for similar grades

Grade Carbon (%) Key applications Heat treatment Comments
20CrNi6 0.17 – 0.23 Gears, shafts, transmission parts Carburizing, quenching & tempering Excellent toughness and wear resistance
16CrNi4 0.14 – 0.19 Automotive gears Case hardening Lower nickel content
En353 0.17 – 0.22 Gear and pinion applications Case hardening Widely used carburizing steel
Aisi 8620 0.18 – 0.23 Automotive and machinery parts Case hardening Common us equivalent

Summary

20CrNi6 is a high-quality chromium–nickel alloy steel optimized for case hardening applications. It is widely used in automotive and engineering industries where wear resistance, toughness, and durability are critical.