37Cr4 alloy steel

Introduction

We manufacture forging ingots, billets, and blooms in alloy steel specifically for 37Cr4, designed for high-strength engineering and automotive applications.

37Cr4 is a medium carbon chromium alloy steel known for its good strength, toughness, and wear resistance. It is commonly used for components subjected to moderate to high mechanical loads and dynamic stresses.

The chromium content improves hardenability and wear resistance, allowing effective through hardening for medium section sizes. 37Cr4 offers good machinability in the annealed condition and maintains dimensional stability after heat treatment, making it suitable for forging and machining operations.

This grade provides a reliable balance between mechanical performance, durability, and cost effectiveness.

Chemical composition

Element	Content (%)	Function / effect
Carbon (c)	0.34 – 0.40	Provides strength and hardness
Manganese (mn)	0.60 – 0.90	Improves hardenability and toughness
Silicon (si)	Max 0.40	Increases strength and elasticity
Chromium (cr)	0.90 – 1.20	Enhances hardenability and wear resistance
Phosphorus (p)	Max 0.035	Controlled impurity; improves toughness
Sulphur (s)	Max 0.035	Controlled impurity; aids machinability

Mechanical properties (typical, depending on condition & heat treatment)

• Tensile strength: 800 – 950 MPa
• Yield strength: 600 – 750 MPa
• Hardness: 26 – 32 HRC
• Impact toughness: Good
• Fatigue resistance: Good

Heat treatment

• Annealing: used to soften the steel for improved machinability prior to further processing.
• Quenching: heating to approximately 830 – 860°c, followed by rapid cooling to achieve a hardened structure.
• Tempering: reheating at controlled temperature to relieve internal stresses and improve toughness while retaining required hardness.

Heat treatment can be optimized to meet specific application requirements.

Key features and benefits

• Good through-hardening capability
• High strength with adequate toughness
• Improved wear resistance due to chromium content
• Good machinability in annealed condition
• Dimensional stability after heat treatment
• Suitable for forging and machining

Typical applications

• Shafts and spindles
• Gears and pinions
• Axles and studs
• Forged components for automotive and machinery
• General engineering parts requiring strength and wear resistance

Equivalent steel grades

37Cr4 is comparable to several international standards, including:

• En 10083 – 37Cr4
• Din 1.7034
• AISI / SAE 5135 (approximate)

(exact equivalence may vary slightly depending on standard and heat treatment condition.)

Why choose 37Cr4 alloy steel?

37Cr4 offers dependable mechanical performance at a competitive cost. Its good hardenability, ease of machining, and consistent heat treatment response make it suitable for a wide range of engineering and automotive applications.

Comparison table for similar grades

Grade	Carbon (%)	Key applications	Heat treatment	Comments
37Cr4	0.34 – 0.40	Shafts, gears, axles	Quenching & tempering	Balanced strength and toughness
41Cr4	0.38 – 0.45	Automotive and machinery parts	Quenching & tempering	Higher strength
En19 (42CrM04)	0.38 – 0.45	High-load components	Q&t	Higher strength due to mo
Aisi 5135	0.33 – 0.38	Automotive parts	Q&t	Approximate us equivalent

Summary

37Cr4 is a versatile chromium alloy steel suitable for through-hardening applications. It delivers reliable strength, wear resistance, and durability for components operating under moderate to high stress conditions.