EN8 carbon steel

Introduction

We manufacture forging ingots, billets, and blooms in carbon steel specifically for EN8, tailored for medium to high-strength engineering applications.

EN8 is a medium carbon steel well known for its excellent combination of strength, toughness, and wear resistance. With higher carbon content than EN3, EN8 offers superior mechanical properties and is suitable for components subjected to moderate to heavy loads. It is one of the most widely used carbon steels in automotive, general engineering, and machinery manufacturing due to its versatility and cost effectiveness.

Chemical composition

Element	Content (%)	Function / effect
Carbon (c)	0.35 – 0.45	Provides higher strength, hardness, and wear resistance
Manganese (mn)	0.60 – 1.00	Improves hardenability, toughness, and tensile strength
Sulfur (s)	Max 0.06	Enhances machinability; controlled to avoid brittleness
Phosphorus (p)	Max 0.06	Improves machinability; excess reduces toughness
Silicon (si)	0.05 – 0.35	Acts as deoxidizer and increases strength
Chromium (cr)	Nil	Not present
Nickel (ni)	Nil	Not present
Molybdenum (mo)	Nil	Not present
Other elements	—	No intentional alloying additions

Mechanical properties (typical values, dependent on heat treatment and section size)

• tensile strength: approx. 550 – 700 MPa
• yield strength: approx. 300 – 450 MPa
• hardness: approx. 170 – 220 hb (up to ~50 hrc after hardening)
• impact toughness: moderate to good
• fatigue resistance: good for repeated load applications

Heat treatment

• annealing: used to soften the material and improve machinability before final machining
• normalizing: refines grain structure and improves strength and toughness
• quenching: heating to ~820 – 860°c followed by oil or water quenching to increase hardness
• tempering: performed after quenching to reduce brittleness and achieve required toughness
• EN8 responds well to quenching and tempering for structural and wear-resistant components

Key features and benefits

• higher strength than low carbon steels
• good wear and abrasion resistance
• balanced toughness and hardness
• good machinability in annealed or normalized condition
• cost-effective alternative to alloy steels for many applications
• suitable for forging, machining, and heat treatment

Typical applications

• shafts, axles, and spindles
• gears, pins, and keys
• bolts, studs, and high-strength fasteners
• automotive and agricultural machinery parts
• forged and heat-treated engineering components

Equivalent steel grades

• EN8 (bs 970)
• aisi 1040 / 1045
• is 1570 gr 40c8
• din c45

Why choose EN8 for your application?

EN8 is the ideal choice when a higher level of strength and wear resistance is required without the cost of alloy steels. Its excellent response to heat treatment, combined with good machinability and availability, makes it a preferred material for medium to heavy-duty engineering components.

Comparison table for similar grades

Grade	Carbon (%)	Key applications	Heat treatment	Comments
EN8	0.35 – 0.45	Shafts, gears, fasteners	Q&t / normalizing	High strength carbon steel
Aisi 1045	0.43 – 0.50	Axles, bolts, pins	Q&t	American equivalent
C45	0.42 – 0.50	Engineering components	Normalized / q&t	European equivalent

Summary

EN8 is a medium carbon steel designed for applications that demand good strength, toughness, and durability. With its ability to be heat treated and machined efficiently,EN8 remains one of the most popular steel grades for general engineering and automotive use.