EN8 vs EN9 vs EN19 vs EN24 — Which Engineering Steel Is Best for Your Application?

Choosing the right engineering steel is critical for ensuring performance, safety, durability, and cost efficiency. In 2025, the four most widely used engineering steel grades are:

EN8 – Medium carbon steel for general engineering
EN9 – Higher carbon steel for wear applications
EN19 (4140) – Chromium-molybdenum alloy steel
EN24 (4340) – Nickel-chromium-molybdenum high-strength steel

Each grade has a different combination of strength, toughness, hardness, machinability, wear resistance, and heat treatment capability. This expert comparison helps industries determine which grade is best.

Chemical Composition — The Core Difference

Grade	Carbon	Alloying Elements	Type
EN8	0.40–0.45%	None	Medium Carbon Steel
EN9	0.50–0.60%	None	High Carbon Steel
EN19	0.40%	Cr, Mo	Alloy Steel
EN24	0.40%	Ni, Cr, Mo	High-Strength Alloy Steel

EN8 & EN9 = simple carbon steels

EN19 & EN24 = alloy steels → much higher performance

Mechanical Strength Comparison

Grade	Tensile Strength	Hardness	Toughness
EN8	Medium	Medium	Medium
EN9	Medium–High	High	Medium
EN19	High	High	High
EN24	Very High	Very High	Very High

Best Overall Strength → EN24

Best Balanced Properties → EN19

Heat Treatment Response

Grade	Quench & Temper	Induction Hardening	Case Hardening
EN8	Good	Good	Limited
EN9	Very Good	Very Good	Limited
EN19	Excellent	Excellent	Good
EN24	Outstanding	Excellent	Good

EN24 performs best under heat treatment.

Wear Resistance

EN9 → High hardness after heat treatment
EN24 → High wear + high toughness
EN8 → Moderate
EN19 → Good wear + excellent fatigue resistance

Best for tools & wear components: EN9

Best for high-impact wear: EN24

Machinability

Grade	Machinability
EN8	⭐⭐⭐⭐⭐ Best
EN9	⭐⭐⭐⭐ Good
EN19	⭐⭐⭐ Medium
EN24	⭐⭐ Difficult due to toughness

If machining cost matters → Choose EN8.

Applications by Grade

EN8 Applications

Shafts
Keys
Studs
General machine parts
Automotive components

EN9 Applications

Gears
Knives
Machinery tools
Wear plates
Crankshafts (light duty)

EN19 Applications

Gears & pinions
High-strength shafts
Oilfield tools
Crankshafts
Connecting rods
Bolts & studs

EN24 Applications

Aircraft landing gear
Motorsport components
Heavy-duty shafts
High-performance gears
Helicopter parts

Which Steel Should You Choose?

Choose EN8 if

Budget is important
You need general purpose steel
Machinability is a priority

Choose EN9 if

You need higher hardness
Component faces regular wear
Application includes tools or gears

Choose EN19 if

You need balanced hardness & toughness
Component faces shock loading
You want a strong, reliable upgrade to EN8

Choose EN24 if

You need maximum strength & toughness
Application involves high impact or load
Used in aerospace or motorsports

Cost Comparison (2025 Industry Range)

Grade	Cost	Reason
EN8	Low	Simple carbon steel
EN9	Medium	Higher carbon content
EN19	Medium–High	Alloy steel
EN24	High	Premium high-strength alloy

Best cost–performance ratio → EN19

Best economy grade → EN8

Premium performance → EN24

Summary Chart

Requirement	Best Grade
Best Machinability	EN8
Best Wear Resistance	EN9
Best All-Round Performance	EN19
Best High-Strength + Toughness	EN24
Best for Impact/Shock Loads	EN24
Best Budget Option	EN8

Conclusion

Engineering steels EN8, EN9, EN19, and EN24 each offer unique strengths. The best grade depends on your application, load conditions, machining requirements, and budget.

EN8 → General engineering, low cost

EN9 → Wear resistance

EN19 → Balanced performance

EN24 → Maximum strength + toughness

For high-quality engineering steel bars, rods, tubes, and precision parts, Moksh Tubes & Fittings LLP provides certified materials with exceptional quality and competitive pricing.

FAQ's

Which steel is better: EN19 or EN24?

EN24 is stronger and tougher. But EN19 is more economical and versatile.

Is EN8 a good engineering steel?

Yes — it is the most commonly used general-purpose engineering steel.

Which grade is best for gears?

Light to medium gears → EN9 High-performance gears → EN19 / EN24

Which steel is best for shafts?

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

Which grade lasts longest?

EN24, due to its superior strength & fatigue resistance.

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