In order to identify the basic information about the rebar that is delivered to a jobsite, it is important to know how to read the mill markings that are stamped on every bar. This is especially critical to ensuring that your materials match up with the specifications in the plans.
Images and bar marking description courtesy of CRSI
The top letter or symbol identifies the producing mill and deformation pattern.
The next marking is the bar size.
The third marking symbol designates the manufacturing material — usually either “S” for carbon-steel (ASTM A615) or “W” for low-alloy steel (ASTM A706).
Finally, there will be a grade marking (4 or 5, for 420 or 520) or by the addition of one line (420) or two lines (520) that must be at least five deformations long.
For more information, please visit www.crsi.org/rebar