Understanding the 0.00623 Coefficient in Round Bar Weight Calculation
The commonly used formula for estimating the theoretical weight of a solid round bar is:
Weight (kg/m) = 0.00623 × Diameter × Diameter
This coefficient (0.00623) is derived from the material density and the cross-sectional area of the bar. Below is a detailed explanation of the origin and use of this value.
1. General Formula for Round Bar Weight
The basic theoretical weight formula is:
Weight (kg/m) = Cross-sectional Area × Density = (π / 4 × d²) × ρ
- d: Diameter (mm)
- ρ: Density (g/cm³)
Make sure all units are consistent — area in mm², density converted to kg/mm³.
2. Derivation Example for 304 Stainless Steel
The density of 304 stainless steel is approximately:
ρ = 7.93 g/cm³ = 7930 kg/m³
Substituting into the formula:
Weight (kg/m) = (π / 4) × d² × (7930 / 1,000,000) ≈ 0.006217 × d²
Rounded for engineering use: 0.00623 × d²
For example:904L Stainless Steel Round Bar Weight Calculation Formula
The theoretical weight per meter of a solid round bar made of 904L stainless steel can be calculated using the following standard formula:
Weight (kg/m) = (π / 4) × d² × ρ
Where:
- d = Diameter in millimeters (mm)
- ρ = Density in kg/mm³
Density of 904L Stainless Steel:
ρ = 8.00 g/cm³ = 8000 kg/m³ = 8.0 × 10−6 kg/mm³
Formula Derivation:
Weight (kg/m) = (π / 4) × d² × 8.0 × 10−6 × 1000
= 0.006283 × d²
Final Simplified Formula:
Weight (kg/m) = 0.00628 × d²
(d is the diameter in mm)
Example:
For a 904L round bar with diameter 50mm:
Weight = 0.00628 × 50² = 0.00628 × 2500 = 15.70 kg/m
3. Application Scope
- This coefficient is suitable for 304/316 stainless steel or any material with density around 7.93 g/cm³
- Shapes: solid round bar, rod, circular billet
- Input: diameter in mm, result in kg/m
4. Reference Coefficients for Other Materials
| Material | Density (g/cm³) | Coefficient (kg/m) |
|---|---|---|
| 904L Stainless Steel | 8.00 | 0.00628 |
| 304 / 316 Stainless Steel | 7.93 | 0.00623 |
| Carbon Steel | 7.85 | 0.00617 |
| Copper | 8.96 | 0.00704 |
5. Conclusion
The coefficient 0.00623 provides a quick and reliable way to calculate the theoretical weight of stainless steel round bars. For other materials, adjust the coefficient according to density.
If you need exact weights, cutting tolerance, or MTC-certified stainless steel bars, please feel free to contact Saky Steel.
Post time: Jun-16-2025