SAE 8617 alloy steel

Introduction

We manufacture forging ingots, billets, and blooms in alloy steel specifically for SAE 8617, tailored for high-performance carburizing and engineering applications.

SAE 8617 is a low carbon nickel-chromium-molybdenum alloy steel designed primarily for case hardening applications. It provides an excellent combination of high surface hardness, strong core toughness, and superior fatigue resistance, making it ideal for components subjected to heavy loads and wear conditions.

The presence of nickel improves toughness and impact strength, while chromium enhances wear resistance and hardenability. Molybdenum contributes to strength retention at elevated temperatures and improves overall mechanical stability. SAE 8617 also offers good machinability in the annealed condition and excellent dimensional stability after heat treatment, making it widely used in automotive and heavy-duty engineering components.

This alloy steel delivers reliable performance, long service life, and cost-effective manufacturing for critical engineering applications.

Chemical composition

Element Content (%) Function / effect
Carbon (c) 0.15 – 0.20 Provides surface hardness after carburizing
Manganese (mn) 0.70 – 0.90 Improves strength and hardenability
Silicon (si) 0.15 – 0.35 Enhances strength and elasticity
Nickel (ni) 0.40 – 0.70 Improves toughness and impact resistance
Chromium (cr) 0.40 – 0.60 Improves wear resistance and hardenability
Molybdenum (mo) 0.15 – 0.25 Improves strength and heat resistance
Phosphorus (p) Max 0.035 Impurity; lower content improves toughness
Sulphur (s) Max 0.040 Improves machinability in controlled amounts

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

  • Tensile strength (core): 900 – 1150 MPa
  • Yield strength: 650 – 850 MPa
  • Surface hardness (after carburizing): 58 – 62 hrc
  • Core hardness: 28 – 38 hrc
  • Impact toughness: high
  • Fatigue resistance: excellent

Heat treatment

  • carburizing: heating between approximately 870 – 930°c to enrich the surface with carbon and improve wear resistance.
  • quenching: rapid cooling after carburizing to produce a hardened martensitic surface layer.
  • tempering: reheating to relieve internal stresses and enhance toughness while maintaining hardness.
  • annealing: used before machining to improve machinability.

The heat treatment process can be customized to achieve required case depth and Mechanical properties for specific engineering applications.

Key features and benefits

  • excellent case hardening capability
  • high surface hardness and wear resistance
  • strong and tough core structure
  • good fatigue strength under cyclic loading
  • superior toughness due to nickel addition
  • good machinability in annealed condition
  • excellent dimensional stability after heat treatment
  • suitable for forging and precision machining

Typical applications

  • automotive gears and transmission components
  • shafts and pinions
  • heavy duty sprockets
  • differential gears
  • aircraft and precision engineering components
  • industrial machine parts requiring high wear resistance
  • forged and carburized load-bearing components

Equivalent steel grades

SAE 8617 has several international equivalents, including:

  • EN353 – case hardening nickel alloy steel
  • 20nicrmo2-2 (close european equivalent)
  • din 1.6523 (approximate equivalent)

Why choose SAE 8617 for your application?

SAE 8617 offers an excellent balance of surface hardness, core toughness, and fatigue resistance. The addition of nickel enhances toughness, while chromium and molybdenum improve wear resistance and strength. This makes SAE 8617 highly suitable for carburized components operating under heavy loads and repeated stress. Its consistent hardenability and dimensional stability also help improve manufacturing efficiency and component reliability.

Comparison table for similar grades

Grade Carbon (%) Key applications Heat treatment Comments
SAE 8617 0.15-0.20 Gears, shafts, automotive parts Carburizing + q&t Nickel improves toughness
En 353 0.17-0.22 Transmission components Carburizing + q&t Widely used european grade
20nicrmo2-2 Similar Heavy duty gears Carburizing + q&t High strength alloy steel
SAE 8620 0.18-0.23 Automotive and engineering parts Carburizing + q&t Common carburizing steel

Summary

SAE 8617 is a low carbon nickel-chromium-molybdenum alloy steel optimized for carburizing applications requiring high surface hardness and strong core toughness. It delivers dependable performance, long operational life, and excellent mechanical reliability for automotive and engineering components.