When we are calculating the weight of general steel we consider 7.85 as the specific weight.During actual weighment of steel is there any possibility that the sp.wt varies by some percentage, if true how much % is allowed.
The specific gravity of steel doesn't vary much from the specific gravity of iron. Stainless steel are slightly more dense, but within a couple of percent.
In DIN 1681: Steel Castings for General use, it mentions that the weight calculation is made using 7,85 kg/dm3. There are some limitations in the actual weight from 5% to 10%. Please note that weight deviation has also to do with the tolerances reached. A good source to look up the specific gravity for each ally is ASM publications (properties and selection).