Product Description: Steel Round Bar 300M / E4340
Steel round bar 300M (a modified version of 4340 steel, also referred to as E4340) is an ultra-high-strength alloy steel widely used in aerospace and mechanical engineering industries. The material is known for its outstanding strength, excellent toughness, and superior fatigue resistance.
General Technical Characteristics
300M steel is an enhanced version of conventional 4340 steel with increased silicon content and an optimized chemical composition. It provides an excellent combination of strength and ductility, along with high reliability under dynamic and cyclic loading conditions.
Key properties:
- ultra-high strength
- high impact toughness
- excellent fatigue resistance
- good hardenability
Chemical Composition
The composition includes alloying elements that ensure superior performance:
- Carbon (C): approx. 0.38–0.43%
- Chromium (Cr): 0.7–0.95%
- Nickel (Ni): 1.65–2.0%
- Molybdenum (Mo): 0.3–0.45%
- Silicon (Si): 1.45–1.80%
- Manganese (Mn): in moderate amounts
Higher silicon content improves strength and fatigue resistance.
Mechanical Properties
After heat treatment, the steel typically demonstrates:
- tensile strength: up to 1800–2000 MPa
- high impact toughness
- excellent fatigue strength
- resistance to deformation
Applications
300M steel round bar is widely used for manufacturing:
- aerospace components
- aircraft landing gear
- shafts and axles
- highly loaded gears
- high-strength fasteners
It is commonly used in aerospace, defense, and heavy engineering industries.
Features
Key advantages include:
- reliability under extreme loads
- superior fatigue resistance
- good toughness
- long service life
Supply Formats and Standards
The material is supplied as round bar:
- hot-rolled bars
- ground or calibrated bars
- various diameters available
The steel complies with:
- AMS 6419 (300M)
- ASTM A29 (E4340)
Steel round bar 300M is an excellent choice for manufacturing critical components where maximum strength, reliability, and resistance to fatigue are essential.
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