Top Industrial Applications of EN8, EN9, EN19 & EN24 Steels in 2025

Engineering steels are the backbone of modern manufacturing, heavy machinery, automotive systems, construction tools, aerospace parts, and industrial equipment. Among these, EN8, EN9, EN19, and EN24 stand out as the most frequently used because they offer:

High strength
Wear resistance
Excellent machinability
Fatigue resistance
Toughness under stress
Cost-effectiveness

In 2025, industries are demanding stronger, more reliable, and more durable components — which has significantly increased the reliance on these four engineering steel grades. This guide covers WHERE and WHY each grade is used.

Automotive Industry – One of the Largest Users

Cars, trucks, tractors, and heavy vehicles rely on engineering steels for structural and load-bearing parts.

EN8 in Automotives

Axles
Shafts
Steering components
Couplings
Bushings

EN9 in Automotives

Gears
Gear racks
Brake components
Wear plates

EN19 (4140) in Automotives

Crankshafts
Connecting rods
Gear shafts
Propeller shafts

EN24 (4340) in Automotives

Racing components
High-stress gears
Transmission shafts
Heavy-duty axles

Oil & Gas, Petrochemical & Energy Industries

High fatigue strength
Resistance to shock loads
Dimensional stability
Heat treatment compatibility

EN19 Applications

Drill collars
Couplings
Valve stems
High-strength studs
Gearbox parts

EN24 Applications

Heavy load-bearing shafts
Downhole tools
High-stress couplings
Impact-resistant equipment

Heavy Engineering & Machinery Manufacturing

Shafts
Rollers
Gear systems
Pinions
Couplings
Machine frames

Typical Grade Applications

EN8 → General-purpose workloads
EN9 → Gears, rollers, knives
EN19 → High torque load shafts
EN24 → High impact machinery

Aerospace Industry – High Performance Requirements

EN24 Applications

Landing gear components
Aircraft shafts
Gear mechanisms
Helicopter rotor parts

EN24’s nickel + chromium + molybdenum combination gives it exceptional strength and fatigue resistance.

Construction, Tools & Material Handling Equipment

Hydraulic systems
Crane parts
Lifting mechanisms
Cutting tools
Blades
Wear-resistant plates

Grade Usage

EN9 → Tools & cutting edges
EN19 → Load-bearing components
EN24 → High-impact mechanisms

Railway & Transportation Industry

Drive shafts
Gear systems
Brake pins
Couplings
Sleeper fasteners

EN19 and EN24 are preferred due to their reliability.

Mining & Earthmoving Equipment

EN24

Rock breaker shafts
Hammer pins
Shovel components

EN19

Power transmission parts
Drilling machine shafts

Industrial Shafts – The Most Common Application

EN8 → General-purpose shafts
EN19 → High-strength shafts
EN24 → Heavy-duty shafts

Gear Manufacturing

Gear Type	Recommended Steel
Light-duty gears	EN8
Medium-duty gears	EN9
High-torque automotive gears	EN19
Racing & aerospace gears	EN24

Summary of Applications by Grade

Grade	Best Applications
EN8	Shafts, studs, machine parts, automotive components
EN9	Gears, knives, rollers, tools, wear components
EN19	Crankshafts, gear shafts, oilfield tools, high-load parts
EN24	Aerospace, racing, heavy-duty equipment, shock-loaded parts

Conclusion

Engineering steels EN8, EN9, EN19, and EN24 play crucial roles in modern industries that demand high mechanical strength, reliability, heat treatment capability, wear resistance, and fatigue performance.

From automotive and aerospace to heavy machinery, oil & gas, and industrial manufacturing, these steels ensure safe and efficient equipment performance.

FAQ's

Which steel has the most applications?

EN19, because it provides the best balance of strength, toughness, and affordability.

What is EN24 mainly used for?

High-impact, high-load applications such as aircraft landing gear, heavy-duty shafts, and performance gears.

Which steel is best for gears?

Medium gears → EN9 Heavy-duty gears → EN19 High-performance gears → EN24

Is EN8 strong enough for machinery parts?

Yes — EN8 is ideal for general engineering, medium-load machinery, shafts, and automotive components.

Which grade lasts longest under wear?

EN9 and EN31 (EN31 not included in this blog but strongest for wear).

Top Industrial Applications of EN8, EN9, EN19 & EN24 Steels in 2025