HOW TO CALCULATE THE WEIGHT OF HOLLOW STEEL PIPES

Given;
External Diameter (D) =150mm = 0.15m
Internal Diameter  (d)  =140mm = 0.14m
Thickness of pipe        =10mm
Length of pipe       (L) =1m
Density of Steel           = 7850 kg/m3

To calculate the weight of hollow steel pipe we have to apply following formula;

WEIGHT = VOLUME x DENSITY OF STEEL

First of all we calculate the volume

Volume = { Area x Length}
             = { 𝝅/4 (D^2 - d^2) } x Length
             = {3.14/4 (0.15)^2 - (0.14)^2 } x 1
             =  0.002276 cum

Now we have the volume = 0.002276 cum
Put this volume value in weight formula

Weight = Volume x Density of steel
            = 0.002276 m3 x 7850 kg/m3
            = 17.87 kg.

Hence 17.87 kg is the weight of 1m size steel hollow pipe whose external dia = 150mm & internal dia = 140mm.