NF A49-502-2:2006 Hot finished structural hollow sections of non-alloy and fine grain steels - Part 2 : tolerances, dimensions and sectional properties.
2006NF A49-502-2:2006 Hot finished structural hollow sections of non-alloy and fine grain steels - Part 2 : tolerances, dimensions and sectional properties.
1997NF A49-502-2:1997 Hot finished structural hollow sections of non-alloy and fine grain structural steels. Part 2 : tolerances, dimensions and sectional properties.