Calculating the weight of a specific 40 * 40 * 3 square pipe (also commonly referred to as square hollow section or SHS) requires understanding these dimensions and applying the standard weight calculation formula.
Understanding the Dimensions
- 40 * 40: This typically indicates the outer dimensions of the square pipe are 40 mm by 40 mm.
- 3: This usually represents the wall thickness of the pipe, which is 3 mm.
So, we have a square tube with:
- Outer Side Length (S) = 40 mm
- Wall Thickness (t) = 3 mm
The only missing piece of information for a total weight calculation is the Length (L) of the pipe. Weight is often calculated per unit length, such as per meter (m) or per foot (ft), if the total length isn’t specified.
Calculation Steps (Weight per Meter)
Let’s calculate the weight per meter using the standard density of carbon steel, which is approximately 7850 kg/m³.
Calculating Weight per Meter (using mm and kg/m³)
-
Convert Dimensions to Meters:
- Outer Side (S) = 40 mm = 0.040 m
- Wall Thickness (t) = 3 mm = 0.003 m
- Length (L) = 1 m (since we’re calculating per meter)
-
Calculate Inner Side Length (S_inner):
S_inner = S - 2t = 0.040 m - 2 * 0.003 m = 0.040 m - 0.006 m = 0.034 m -
Calculate Cross-Sectional Area of Steel (A_steel):
A_steel = Outer Area - Inner Area = S² - S_inner²A_steel = (0.040 m)² - (0.034 m)²A_steel = 0.0016 m² - 0.001156 m² = 0.000444 m² -
Calculate Volume of Steel per Meter (V):
Volume (V) = A_steel × Length = 0.000444 m² × 1 m = 0.000444 m³ -
Calculate Weight per Meter:
Weight = Volume × Density = V × ρWeight = 0.000444 m³ × 7850 kg/m³Weight ≈ 3.4854 kg
Therefore, a 40 * 40 * 3 square pipe weighs approximately 3.49 kg per meter.
Alternative Calculation (using mm and kg/mm³)
Alternatively, we can keep dimensions in mm and use density in kg/mm³.
Density (ρ) = 7850 kg/m³ = 7850 / (1000³) kg/mm³ = 0.00000785 kg/mm³.
- Outer Side (S) = 40 mm
- Wall Thickness (t) = 3 mm
- Inner Side (S_inner) = 40 – 2*3 = 40 – 6 = 34 mm
- A_steel = 40² – 34² = 1600 – 1156 = 444 mm²
- Volume per meter (L=1000 mm) = A_steel * L = 444 mm² * 1000 mm = 444,000 mm³
- Weight = Volume * Density = 444,000 mm³ * 0.00000785 kg/mm³ ≈ 3.4854 kg
The result is the same: approximately 3.49 kg per meter.
Total Weight
To find the total weight of a specific piece of this pipe, multiply the weight per meter by the total length in meters. For example, a 6-meter long piece would weigh:
Total Weight = Weight per Meter × Length = 3.49 kg/m × 6 m ≈ 20.94 kg
This detailed steel calculation shows how to determine the weight per meter for a standard 40x40x3 square pipe, a common requirement in construction and fabrication.
