What is the [approx] density of steel? 5 tonnes/cubic metre 6 tonnes/cubic metre 7 tonnes/cubic metre 8 tonnes/cubic metre

Ranges between 7,750  kg/m3  and 8,050 kg/m3  roughly  8 tonnes/cubic metre.

The density of steel varies based on the alloying constituents but usually ranges between7,750 and8,050 kg/m3 (484 and503 lb/cu ft), or7.75 and8.05 g/cm3 (4.48 and4.65 oz/cu in).

between7,750 and8,050 kg/m3

It is approximately "8 tonnes/cubic metre"

Please see the following link: http://en.wikipedia.org/wiki/Carbon_steel

The density is7850 kg/m3 so close to8 tons/m3

7,9T/cubic meter

I agree, and therefore my answer is between7,750 and8,050 kg/m3