| Weight | = | Volume x density | |
| Since its cylindical shape | |||
| Volume of bar | = | pi()*h*(d²)/4 | mm³ |
| where | h is height of cylinder bar | ||
| d is diameter in mm | |||
| Weight density of steel | = | 7850 | kg/m³ |
| Here we considering for 1m length, so h = 1m | |||
| Volume of bar | = | pi()*h*(d²)*(10⁻⁶)/4 | m³ |
| = | pi()/4*h*(d²)*(10⁻⁶) | ||
| Here we have coverted dia from mm to m | |||
| Volume of bar | = | (7.85*(10⁻⁷))*(d²) | m³ |
| Weight of bar | = | Weight density x Volume | |
| or unit weight of steel | = | 7850*(7.85*(10⁻⁷))*(d²) | |
| = | 0.00616225 | *d² | |
| or can be written as | = | d²/ | 162 |
| where d is diameter of bar in mm | |||
| Example | |||
| 25mm bar weight per meter = | 25*25/162 | ||
| = | 3.858024691 | kg | |
| Weight of steel | = | (d²/162)*length | |
