C38 carbon steel

Introduction

We manufacture forging ingots, billets, and blooms in carbon steel specifically for C38, designed for medium strength engineering applications where good toughness, machinability, and reliable mechanical performance are required. C38 is a medium carbon, unalloyed engineering steel that offers a balanced combination of strength and toughness with better machinability than higher carbon grades such as C45, C48, and C50.

C38 responds well to normalizing and quenching & tempering, providing improved Mechanical properties while maintaining good ductility. This grade is widely used in general engineering, automotive, and machinery applications where cost-effectiveness and processability are important.

Chemical composition

Element	Content (%)	Function / effect
Carbon (c)	0.35 - 0.40	Provides moderate strength and hardness
Manganese (Mn)	0.60 - 0.90	Improves hardenability and toughness
Silicon (si)	0.15 - 0.35	Increases strength and acts as deoxidizer
Phosphorus (p)	Max 0.050	Impurity; limited to maintain toughness
Sulphur (s)	Max 0.050	Improves machinability when controlled
Chromium (cr)	Nil	Not intentionally added
Nickel (ni)	Nil	Not present
Molybdenum (mo)	Nil	Not present
Other elements	—	No significant alloying additions

Mechanical properties

(Properties may vary depending on section size and heat treatment conditions)

• Tensile strength: 520 - 680 MPa
• Yield strength: 300 - 420 MPa
• Hardness: 170 - 220 HB (up to ~30–35 hrc after heat treatment)
• Impact toughness: good
• Wear resistance: moderate

Heat treatment

• annealing: used to improve machinability and soften the steel for ease of processing.
• normalizing: refines grain structure and improves strength and toughness balance.
• quenching: heating to approximately 800 - 840°c followed by oil or water quenching to increase hardness.
• tempering: performed to relieve internal stresses and improve toughness while retaining required strength.

Proper heat treatment ensures consistent performance of C38 in engineering applications.

Key features and benefits

• good balance of strength and toughness
• excellent machinability compared to higher carbon grades
• good response to normalizing and heat treatment
• suitable for forging and machining applications
• cost-effective and widely used material
• stable and reliable mechanical properties

Typical applications

• shafts and axles
• gears and pinions for moderate loads
• automotive and machine components
• fasteners and general engineering parts
• forged and machined components

Equivalent steel grades

C38 has several comparable and equivalent grades, including:

• EN8 / EN8D (BS standard range)
• C35 / C40 (DIN / EN 10083 range)
• AISI 1038 (american standard)
• IS 1570 (part 2) - indian standard

Why choose C38 for your application?

C38 offers an ideal combination of machinability, toughness, and adequate strength, making it suitable for components that do not require extreme hardness. Its excellent processability and economical cost make it a practical choice for a wide range of general engineering and automotive applications.

Comparison table for similar grades

Grade	Carbon (%)	Key applications	Heat treatment	Comments
C38	0.35 - 0.40	Shafts, gears, machine parts	Normalizing / q&t	Good machinability and toughness
C45	0.40 - 0.50	General engineering parts	Q&t	Higher hardness than C38
C48	0.45 - 0.50	Gears and axles	Q&t	Higher strength
AISI 1038	0.35 - 0.40	Automotive & machinery parts	Q&t	American equivalent

Summary

C38 is a medium carbon steel designed for applications requiring good toughness, machinability, and reliable mechanical performance. With consistent quality, good heat treatment response, and cost-effective pricing, C38 remains a popular choice for general engineering use.