### How to calculate the weight of hollow rectangular steel section?/Calculating the weight of mild steel rectangular hollow tube.

For the calculation procedure, go through the following steps.👇

Let us consider a hollow rectangular mild steel tube or pipe of dimension 70mm × 40mm.× 3mm. as shown in the fig. below. Let us calculate the weight for the pipe having a 3-meter length. Hollow rectangular steel section.

Here, thickness T = 3mm.  breadth B = 70mm, depth D = 40mm., and length L =3m. Hollow rectangular MS tube.

First, we will calculate the sectional area in two parts, the orange-colored part area as A1, and green colored part area as A2. Area A1 = [Breadth( B) × Thickness (T) × 2nos. ]

= [70mm × 3mm. × 2nos.]

By converting mm. unit into meters, we get

= [0.07 × 0.003 × 2 ]

A1 = 0.00042 sqm.

Area A2  = [{D - ( 2 × T )} × T × 2 nos.]

= [ {40 - ( 2  × 3)}  × 3  × 2 nos.]

= [ 34 mm. × 3mm. ×2nos.]

By converting mm. unit into meters, we get

= [ 0.034m. × 0.003m. × 2nos.]

A2 = 0.000204 sqm.

Now, total sectional area

A = [A1 +A2]

= [0.00042 +0.000204]

A= 0.000624 sqm.

As you know,

volume = [ area × length ]

= [A  × L ]

= [ 0.000624 × 3]

V 0.001872 cum.

The density of mild steel is 7850 kg./cu.m.

So, the weight of the hollow rectangular MS pipe

= [volume × density]

= [0.001872 × 7850]

#### =  14.695kg.

The weight of the rectangular steel section/meter.

= [14.695kg ÷ 3m.]

= 4.8983 kg./m.

= 1.493 kg / ft.

(As 1m = 3.28084 ft.)

For you 👇

### Alternate method:

First, we will calculate the total area inclusive of the hollow part, and then we will deduct the inner hollow portion (shown in green color) of the pipe.

Area a1   =[ B × D]

= [70mm. × 40mm.]

By converting mm. unit into meters, we get

a1 = [0.07 × 0.04]

a1 = 0.0028 sqm.

Area a2  = [{ B - (2T)} × { D - ( 2T)}]

=  [{ 70 -( 2 × 3)} × { 40 - (2 × 3)}]

= [ 64mm.× 34 mm.]

( i.e. inner green hollow part )

By converting mm. unit into meters, we get

= [0.064m.  ×0.034m.]

a2 = 0.002176 sqm.

Now, the total sectional area

A = [a1 - a2]

= [0.0028 - 0.002176]

A = 0.000624 sqm.

Note: We got the same area (A ) as calculated before.

Volume = [area  × length]

= [0.000624 ×3]

V =  0.001872 cum.

So, the weight of the hollow rectangular MS pipe

= [volume × density]

= [0.001872 × 7850]

### = 14.695 kg.

PART2 👈Back

Thank you for going through this calculation😃.

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