SAE 15B25 Boron (CHQ) Steel
The Next Level of Formable Strength.
When manufacturing fasteners and forged parts, the challenge is always to balance formability with final strength. SAE 15B25 rises to this challenge. As a manganese-boron steel, it offers the excellent cold heading properties of a lower-carbon grade while providing significantly higher strength and hardenability. It is the ideal choice for components that require a step up in performance without sacrificing manufacturing efficiency.
The High-Strength Forging Standard
Higher Core Strength
The higher manganese content provides a notable increase in core strength and toughness over 10B21.
Excellent Formability
Engineered as a Cold Heading Quality (CHQ) steel for efficient, crack-free forming of complex parts.
Enhanced Hardenability
The synergy of manganese and boron ensures a deep and uniform hardness after heat treatment.
Ideal for Fasteners
The increased strength makes it a superior choice for larger diameter or higher property class (e.g., 10.9) bolts and studs.
Technical Specifications
Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.19 - 0.25 |
| Manganese (Mn) | 0.9 - 1.2 |
| Boron (B) | 0.0005 - 0.003 |
| Phosphorus (P) | 0.030 Max |
| Sulphur (S) | 0.035 Max |
Common Applications
Equivalent International Grades
| Standard | Grade |
|---|---|
| DIN / W-Nr. | 27MnB4 |
Frequently Asked Questions about 15B25
When should I choose 15B25 over 10B21?
Choose 15B25 when your component requires higher core strength and toughness than 10B21 can provide. Its higher manganese content makes it suitable for producing larger or higher property class fasteners (like Class 10.9) that need to withstand greater loads.
What is the role of Manganese in 15B25?
Manganese is a key alloying element that works in synergy with Boron. It significantly increases the steel's strength and, most importantly, its hardenability. This allows a **15B25 bright bar** to achieve deep, uniform hardness through heat treatment, which is critical for reliable performance.
The Assurance of a Stronger Connection
When a connection must withstand greater forces, the material itself must be elevated. The Marbrite Standard for SAE 15B25 is our guarantee of a precisely controlled chemistry that delivers a clear performance upgrade. We provide **15B25 CHQ steel** with the perfect balance of formability and enhanced strength, ensuring the fasteners you produce have the integrity to handle higher loads and provide a stronger, more reliable connection.