25CrM04 alloy steel

Introduction

We manufacture forging ingots, billets, and blooms in alloy steel specifically for 25CrM04, designed for high-strength engineering applications requiring good toughness, weldability, and resistance to fatigue.

25CrM04 is a low carbon chromium–molybdenum alloy steel known for its excellent combination of strength and toughness. It is widely used for components subjected to dynamic loads and moderate temperatures, particularly where good weldability is required.

Chromium improves hardenability and wear resistance, while molybdenum enhances strength, creep resistance, and resistance to temper embrittlement. 25CrM04 offers good machinability in the normalized or annealed condition and maintains dimensional stability after heat treatment.

Chemical composition

Element	Content (%)	Function / effect
Carbon (c)	0.22 – 0.29	Provides strength with good toughness
Manganese (mn)	0.60 – 0.90	Improves hardenability and strength
Silicon (si)	Max 0.40	Enhances strength and elasticity
Chromium (cr)	0.90 – 1.20	Improves hardenability and wear resistance
Molybdenum (mo)	0.15 – 0.30	Increases strength and temper resistance
Phosphorus (p)	Max 0.035	Controlled impurity
Sulphur (s)	Max 0.035	Controlled impurity

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

• Tensile strength: 800 – 1000 MPa
• Yield strength: 600 – 750 MPa
• Hardness: 25 – 32 HRC
• Impact toughness: Very good
• Fatigue resistance: Excellent

Heat treatment

• Normalizing: used to refine grain structure and improve mechanical properties.
• Annealing: applied to improve machinability before further processing.
• Quenching: heating to approximately 830 – 860°c, followed by oil or water quenching to achieve higher strength.
• Tempering: performed to relieve internal stresses and obtain the desired balance of strength and toughness.

Heat treatment can be tailored based on application requirements.

Key features and benefits

• Excellent strength-to-toughness ratio
• Good weldability compared to higher carbon grades
• High fatigue resistance
• Good wear resistance
• Dimensional stability after heat treatment
• Suitable for forging, welding, and machining

Typical applications

• Shafts and axles
• Automotive and aerospace components
• Pressure vessels and structural parts
• Forged components
• High-strength welded structures

Equivalent steel grades

25CrM04 has several international equivalents, including:

• En 10083 – 25CrM04
• Din 1.7218
• AISI / SAE 4130

(exact equivalence depends on condition and heat treatment.)

Why choose 25CrM04 alloy steel?

25CrM04 is ideal for applications that demand high strength, good toughness, and reliable weldability. Its excellent fatigue performance and consistent heat treatment response make it a preferred material for critical engineering components.

Comparison table for similar grades

Grade	Carbon (%)	Key applications	Heat treatment	Comments
25CrM04	0.22 – 0.29	Shafts, welded structures	Q&t / normalized	Good weldability
42CrM04	0.38 – 0.45	Heavy-duty components	Q&t	Higher strength
Aisi 4130	0.28 – 0.33	Aerospace, automotive	Q&t	Us equivalent
En19	0.38 – 0.45	High-load parts	Q&t	Higher carbon

Summary

25CrM04 is a versatile chromium–molybdenum alloy steel offering high strength, toughness, and durability. It is widely used in automotive, structural, and pressure equipment applications where reliable performance is essential.