Precise Weight & Cost Estimation for Industrial Applications
Calculate Weight & Price
Enter the dimensions of your cast iron round bar below.
mm
inch
Standard cast iron bars range from 20mm to 500mm.
Please enter a valid positive diameter.
mm
meter
inch
feet
The cutting length of the round bar.
Please enter a valid positive length.
Quantity must be at least 1.
$/kg
Estimated market price per kilogram for Grey Cast Iron.
Total Weight
0.00 kg
Weight Per Bar
0.00 kg
Total Volume
0.00 m³
Estimated Total Cost
$0.00
Calculation Basis: Weight = Volume × Density.
Using standard Grey Cast Iron density of 7,200 kg/m³ (0.26 lbs/in³).
Volume is calculated as π × r² × length.
Standard Weight Reference Table (1 Meter Length)
Diameter (mm)
Weight (kg/m)
Cost Estimate ($)
Table 1: Comparative weights for standard diameters based on inputs.
Weight vs. Diameter Curve
Figure 1: Exponential increase in weight as bar diameter increases (fixed 1m length).
Understanding the Cast Iron Round Bar Weight Calculator
What is a Cast Iron Round Bar Weight Calculator?
A cast iron round bar weight calculator is an essential engineering and procurement tool designed to estimate the total mass and cost of cast iron stock materials. It is primarily used by machinists, estimators, and engineers to determine shipping requirements, material handling needs, and raw material costs before purchasing.
Unlike steel, cast iron has a specific density range due to its graphite content. This calculator uses the specific gravity of standard Grey Cast Iron to provide accurate estimations. It helps avoid the common misconception that all ferrous metals weigh the same; cast iron is generally lighter than steel (approx 7.2 g/cm³ vs 7.85 g/cm³), affecting both logistics and structural calculations.
Key Insight: Using an accurate cast iron round bar weight calculator prevents over-ordering material and helps in precise quoting for machining projects.
Cast Iron Round Bar Weight Calculator Formula
The core mathematics behind the cast iron round bar weight calculator involves determining the cylindrical volume of the bar and multiplying it by the material density.
The step-by-step derivation is as follows:
Convert Units: Ensure all dimensions (diameter and length) are converted to a standard unit, typically meters (m) or centimeters (cm).
Calculate Radius: Divide the diameter by 2 ($r = d / 2$).
Calculate Area: Use the circle area formula ($A = \pi \times r^2$).
Calculate Volume: Multiply the cross-sectional area by the length ($V = A \times L$).
Calculate Weight: Multiply volume by density ($W = V \times \rho$).
Table 2: Variables used in calculation
Variable
Meaning
Metric Unit
Standard Value
$d$
Diameter
mm
Input
$L$
Length
m
Input
$\rho$ (Rho)
Density
kg/m³
~7,200
$W$
Weight
kg
Result
Practical Examples
Example 1: Machining Prototype
A workshop needs to machine a pulley from a cast iron round bar.
Input: Diameter = 150 mm, Length = 500 mm (0.5 m), Quantity = 1.
Calculation:
Radius = 0.075 m
Volume = 3.14159 × (0.075)² × 0.5 ≈ 0.008836 m³
Weight = 0.008836 m³ × 7200 kg/m³
Result: Approx 63.6 kg per piece.
Financial Impact: At $1.50/kg, the material cost is approx $95.40.
Example 2: Production Run
A foundry is supplying stock for a production run of bushings.
Result: Single bar weight is approx 28.27 kg. Total weight for 50 bars is 1,413.5 kg.
Logistics: This exceeds the capacity of a standard pickup truck (often limited to 1000kg), requiring a heavy-duty delivery vehicle.
How to Use This Calculator
Using the cast iron round bar weight calculator is straightforward:
Select Diameter Unit: Choose between millimeters (mm) or inches.
Enter Diameter: Measure the cross-section of the bar.
Enter Length: Input the total length of the bar to be cut or purchased.
Input Price (Optional): If you know the current market rate per kg, enter it to get a cost estimate.
Review Results: The tool instantly calculates the total weight and cost.
Key Factors That Affect Weight Results
While the formula is precise, real-world factors can influence the actual weight of cast iron round bars:
Material Grade Density: Grey cast iron (ASTM A48) has a density around 7.15-7.25 g/cm³, while Ductile Iron (ASTM A536) is slightly denser at 7.3 g/cm³. This calculator uses an average of 7.2 g/cm³.
Dimensional Tolerances: Cast bars are not perfectly round. They often have a "casting tolerance" or oversize allowance to permit machining cleanup. A "50mm" bar might actually measure 52mm raw, increasing weight by ~8%.
Inclusions and Porosity: Poor quality casting may have internal air pockets (porosity), making the actual bar lighter than the theoretical calculation.
Surface Finish: Rough cast surfaces add slight volume compared to a center-ground polished bar.
Cost Fluctuations: Material price per kg changes based on global scrap metal rates, fuel costs for smelting, and supply chain logistics.
Scrap & Kerf Loss: When calculating for purchasing, remember to add margins for saw cuts (kerf loss) and machining waste. The calculated weight is the solid weight, not the shipping weight if packaged.
Frequently Asked Questions (FAQ)
Q: Is cast iron heavier than steel?
No. Steel is denser (approx 7.85 g/cm³) than cast iron (approx 7.20 g/cm³). A steel bar of the same size will weigh about 9% more.
Q: How accurate is this cast iron round bar weight calculator?
It is theoretically accurate to within 1-2%. However, due to casting tolerances (oversizing), actual raw bars often weigh slightly more than the nominal size indicates.
Q: Can I use this for Ductile Iron or SG Iron?
Yes, but note that Ductile Iron is slightly denser (7.3 g/cm³). For critical lifting applications, add a 1.5% safety margin to the result provided here.
Q: Does the calculator include the price of shipping?
No, the "Estimated Total Cost" only reflects the raw material cost based on the price-per-kg input. Shipping is an extra logistical cost.
Q: What is the standard length of a cast iron bar?
Cast iron bars are typically cast in continuous lengths of 2 to 3 meters (approx 6 to 10 feet), but can be cut to any custom length.
Q: Why is knowing the weight important?
It is crucial for quoting shipping costs, ensuring safe lifting limits on cranes/forklifts, and estimating raw material costs for machining bids.
Q: What if my bar is hollow (Cast Iron Tube)?
This calculator is for solid round bars only. For tubes, you must subtract the volume of the inner hole from the outer volume.
Q: How do I calculate weight in pounds (lbs)?
The calculator automatically provides weight in kilograms. To convert to lbs manually, multiply the kg result by 2.20462.