BS970 817M40T EN24T

BS970 817M40T EN24T

BS970 817M40T / EN24T – High-Performance Alloy Steel

Versatile, Strong & Wear-Resistant for Demanding Applications

BS970 817M40T / EN24T is a high-strength, Nickel-Chromium-Molybdenum alloy steel renowned for its exceptional wear resistance, toughness, and machinability. This material is widely used across industries requiring through-hardened components that must endure high stress, impact, and wear conditions.

Why Choose 817M40T / EN24T?

High Tensile Strength & Toughness – Excellent performance under dynamic and impact loading.
Superior Wear Resistance – Designed to withstand abrasion and fatigue, ideal for moving components.
Excellent Machinability – Readily machineable in the hardened and tempered “T” condition.
Flexible Supply Options – Available in bright drawn, turned, hot rolled, and forged block form.
Custom Sizing – Forged blocks can be cold sawn to exact dimensions, reducing machining time.

Material Characteristics & Properties

Mechanical Properties (Typical in Hardened & Tempered “T” Condition)

  • Tensile Strength: 850 – 1000 N/mm²
  • Yield Strength: 680 N/mm² (approx.)
  • Hardness (HB): 248 – 302
  • Ductility: High, ensuring good elongation and impact resistance

Heat Treatment Options

Through Hardening – Achieves uniform strength and wear resistance throughout the component.
Tempering – Enhances toughness while maintaining hardness, making it suitable for high-stress applications.
Forged Block Availability – Cold sawn to custom sizes, reducing material waste and processing costs.

Ideal Applications for 817M40T / EN24T

This alloy steel is a trusted choice in precision engineering due to its ability to withstand high loads, wear, and shock forces. It is commonly used in:

Automotive & Motorsport

  • Axles
  • Gears
  • Drive shafts

Heavy Machinery & Construction

  • High-load pins
  • Structural studs
  • Precision-engineered fasteners

Aerospace & Engineering

  • Aircraft landing gear components
  • Wear-resistant machine parts
  • Custom-fabricated industrial tools

Its strength, durability, and processing flexibility make it one of the most widely used engineering steels in high-performance applications.

Stock Availability & Ordering

We supply BS970 817M40T / EN24T in a variety of forms and sizes, including:

Bright Drawn, Turned & Hot Rolled Bars – Ready for immediate machining & use
Forged Blocks – Available for custom cold sawing to specific dimensions
Custom Heat Treatment Options Available

Call us on: 01902 341705
Email us at: enquiries@midlandbrightsteels.co.uk

Need Help Selecting the Right Material?

Our team is happy to provide technical guidance to ensure you choose the best steel grade for your application.

817M40T / EN24T

BS970: 1955 BS970: 1991 Description
EN24T 817M40T Bright/Black 1.1/2% nickel chromium molybdenum steel
Chemical Analysis
Car 0.36/0.44
Si 0.10/0.40
Mang 0.45/0.70
Phos 0.035 max
Sul 0.040 max
Moly 0.20/0.35
Nick 1.30/1.70
Mechanical Properties
Tensile Strength N/MM2 Min Rm 850/1000
Yield Stress NIMM2 Min Rm 700
Elongation A Min% on 5.65√SO 9
Izod Min 54
Kcv Min -
Proof Stress 0.2% N/MM2 Min 680
Brinell Hardness 248/302
International Specification Comparison
BS 970:1991 817M40T
BS 970: 1955 EN24T
German Din 34NiCrMo6
French Afnor 35NCD6
Swedish SS 2541
American SAE 4340
European Steel No 1.6582
European Steel Name 34CrNiMo6
European Standard EN10277-5
Quick View System
Machineability 40
Weldability Pre / post heat precaution required
Hardenability High strength up to 100mm dia
Selection Guide and Usage Examples Popular direct hardening steel with good tensile. ductility, shock and wear resistance properties
Size Range Summary
Rounds IMP 3/8" -3" dia
MM 10mm -310mm dia

Make an Enquiry

    Phone: +44 (0)1902 341 705
    Fax: +44 (0)1902 340 283
    Email: enquiries@midlandbrightsteels.co.uk