ASTM A 108 r (Straightness)

    Straightness tolerances, (mm maximum deviation) from Straightness in any 3048 mm portion of the bar
size  length  maximum of Carbon range
0,28% or less
  maximum of Carbon range
over 0,28% and all grades thermally treated
     
mm mm rounds squares, hexagons   rounds squares, hexagons
less than
15,88
less than
4572
3,17 4,76   4,76 6,35
less than
15,88
4572
and over
3,17 7,94   7,94 9,53
15,88
and over
less than
4572
1,59 3,17   3,17 4,76
15,88
and over
4572
and over
3,17 4,76   4,76 6,35
All grades quenched and tempered or normalized and tempered to HB 302 max befor cold finishing; and all grades stress relieved or annealed after cold finishing. Straightness tolerances are not applicable to bars having HB hardness exceeding 302.
a) The foregoing tolerances are based on the following method of measuring straightness: Departure from straightness is measured by placing the bar on a level table so that the arc or departure from straightness is horizontal, and the depth of the arc is measured with a feeler gage and a straightedge.  
b) It should be recognized that straightness is a perishable quality and be alterated by mishandling. The preservation of straightness in cold-finished bars requires the utmost care in subsequent handing. Specific straightness tolerances are sometimes required for carbon and alloy steels in which case the purchaser should inform the manufacturer of straightness tolerances and the methods to be used in checking the straightness.