
Round Billet Diameter 300mm 40Cr
Our 300mm diameter Round Billet is manufactured from high-quality 40Cr alloy steel
This table compares the technical specifications of HRB400 32mm rebar (specialized for heavy concrete reinforcement) and Q345B steel (high-strength structural material), highlighting their complementary roles in demanding construction projects.


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Product details
| Parameter | HRB400 Rebar 32mm | Q345B Steel | Unit | Remarks |
|---|---|---|---|---|
| Material Grade | HRB400 (High-Strength Deformed Reinforcing Bar) | Q345B (Low-Alloy High-Strength Structural Steel) | — | Both comply with Chinese national standards |
| Chemical Composition | C ≤0.25%, Si ≤0.80%, Mn ≤1.60%, P ≤0.045%, S ≤0.045%, with trace Nb, V, Ti | C ≤0.20%, Si ≤0.50%, Mn 1.00–1.60%, P ≤0.040%, S ≤0.040%, with trace Nb, V, Ti | — | Alloying elements enhance strength in both grades |
| Diameter/Section | 32 | N/A (varies by form: profiles, plates, bars) | mm | 32mm diameter for heavy-duty reinforcement; Q345B available in multiple forms |
| Weight per Meter | 6.31 | N/A (varies by section/thickness) | kg/m | Calculated for 32mm rebar; Q345B weight depends on specific form |
| Length Range | 6000–12000 (customizable) | 6000–12000 (customizable) | mm | Standard lengths for large-scale construction projects |
| Yield Strength (Minimum) | ≥400 | ≥345 | MPa | Both offer high load-bearing capacity for critical structures |
| Tensile Strength | 540–680 | 470–630 | MPa | Typical range at room temperature |
| Elongation (δ5, Minimum) | ≥16 | ≥22 | % | Ensures ductility for seismic and dynamic load resistance |
| Impact Toughness | ≥34 (at 20°C) | ≥34 (at 20°C) | J | Longitudinal specimens; resistance to sudden impact loads |
| Surface Treatment | Deformed (ribbed) for concrete bonding | Mill finish, hot-dip galvanized, or epoxy-coated | — | HRB400 ribs enhance concrete adhesion; Q345B coatings improve corrosion resistance |
| Manufacturing Standard | GB 1499.2-2018 | GB/T 1591-2018 | — | Adheres to Chinese standards for structural materials |
| Typical Applications | Heavy-duty reinforced concrete (bridges, high-rise columns, large foundations) | Heavy/medium structural components (bridge girders, industrial frames, heavy machinery supports) | — | Often used in coordinated heavy-infrastructure projects |
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Our 300mm diameter Round Billet is manufactured from high-quality 40Cr alloy steel


Our Round Billet product line offers versatile carbon steel billets manufactured according

The Large Square Billet 250x250mm Q345B is a premium low-alloy high-strength steel
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