The cheapest steel plate is the one you only have to buy once. Nothing burns fabrication hours faster than plate that arrives out of flat, because every downstream operation inherits the error.
Camber is the banana along the length: the edge refuses to run straight against the cutting table rail, so a plasma or laser path set from one datum end wanders across the width, and nested parts come out tapered or off-center. Flatness is different: it is the waviness across the surface, and it decides whether the plate sits flat on the machine bed or rocks and shifts mid-cut.
Standards put numbers on both. A common mill guarantee for hot-rolled structural plate allows flatness deviations that shrink as thickness grows, and camber is usually limited to a few millimetres per metre of length. Tighter requirements, such as flatness under 3 mm per 2 m for machine beds or ship panels, are achievable, but they belong in the order because the mill only certifies what was specified.
Three practical habits. First, measure on arrival with a straightedge and wedge gauges while the plate is still on the delivery truck; claims made two weeks later are hard to win. Second, order levelled plate when parts are thin and precision matters; roller levelling after purchase costs more than buying it flat. Third, remember that cutting itself releases stress, so a plate that measures flat can still bow after a long seam cut; sequencing the cuts is your fabrication-side fix.
Good steel does not need surprises. Specify the tolerance, check it on arrival, and the rest of the process stays boring, exactly as it should be.
We supply A572 Grade 50, S355 and other structural plates with certified flatness and camber tolerances to your drawing requirements.
