When inspecting the steel raw materials; It can be checked for the thickness around its edges by use of thickness gauge while it's impossible to check its mid parts due to no access to apply the gauge. To clarify this, , we can calculate it by calculation formula theoretically; please see the following data:

The science is true / equal as always on the basis of theoretical base formula regardless of simple or complicated thing;

eg., for your perceptive reality simply:

    Steel material size:

    5.8 mm thickness  x 100 mm length x 100 mm width
   
    

      5.8 mm thickness

Theoretical calculation:

100 mm x 100 mm x 5.8 mm=58,000 mm  x @7.85 ( S.G. of iron )=455,300

Thus,   455,300 ÷ 1,000,000=0.4553 kgs

∴ 0.4553 x 1000=455 grams

Actual weighing by use of weighing scale:

                450 grams ( 5 grams difference is within tolerance : 0.1 % )

So, we can believe that theoretical calculation of the sample specimen is the same as its actual weighing.

●Besides;

On the basis of this method; we can get steel raw material thickness without thickness gauge as below:

If we know a steel sample weight ( size: 100 mm x 100 mm with S.G.@7.85 ) after weighing: 125,600 grams;

However, if we don't know its thickness ?

it can be defined by the theoretical calculation method easily simply:

125,600 grams ÷ 78,500 ( area x sg.;@7.85: 100 x 100 x 7.85 )=1.6 mm t ( thickness)

Conclusion:

By use of these technical theory; we can clarify steel raw materials' reality on the spot:

a) in case we know its weight of sample ( eg.,100 mm x 100 mm ), but not its thickness known.

b)in case we know its cubic size of sample ( eg., 100 mm x 100 mm x 1.6 mm t ), but not its weight known.