How do you calculate the weight of a round steel rod?

Answer 1

To calculate the weight of a length of steel rod, you require two other pieces of information:

1. density
2. radius

The density of mild steel is 7850 kg/m3 however alloy steels can have densities of up to 8050 kg/m3

To calculate the weight of the steel rod, you must first calculate it's mass.

Mass = Density x Volume

Cross sectional Area (CSA) = pi x radius2

Volume = length x CSA

The weight of the bar is equal to it's mass multiplied by gravitational acceleration (g).

Therefore the weight of the bar of length L equals:

Weight = g x density x pi x radius2 x L

Where:

Weight (N)

g = 9.82 ms-2

density = 7850 to 8050 kg/m3

radius (m)

L = length (m)

Answer 2

For the weight of a round bar you need to know two things. The volume and the density of the material.

You can take the cross sectional area and multiply that times the length to get the volume. Make sure both numbers use the same unit of measure (in X in^2) or your numbers will not come out correctly.

The density of material can be found online or in a materials text book from engineering coursework. Make sure the units of measure cross multiply correctly to cancel each other out or once again the answer will be wrong.