Most steel disputes are not discovered at the mill — they are discovered six weeks later, at the fabricator, when the material will not weld or the galvanizing flakes. By then the container is empty and the money is spent. Here is the verification sequence we run on our own orders, and the one we recommend to every buyer.
Every shipment should carry an EN 10204 3.1 mill test certificate issued per heat or per coil. Check three things before anything else: that the heat number on the certificate matches the number stencilled on the material; that the mechanical values (yield, tensile, elongation) meet the standard you specified; and that the chemical analysis is within the grade limits. A certificate that does not match the material is worse than no certificate.
SGS, BV and Intertek all run inspection services in the main steel-producing regions. For a few hundred dollars, an inspector will check dimensions against the standard, verify surface condition, witness the loading, and photograph everything. The report is dated before the vessel sails, which makes any claim straightforward.
Ask for three photo sets: the material before packing, the packing itself, and the container loading with the door open. A stuffing record that shows the bundles strapped, the dunnage in place and the container number visible settles most "arrived damaged" disputes in minutes.
For critical orders, keep the sampling simple: check dimensions on a fixed number of pieces per bundle, and retain one sample piece per heat with its stencil visible. If a claim has to be made, that piece is the evidence.
None of this is complicated, and none of it is expensive relative to the value of a container. What it requires is agreeing the verification steps before the proforma invoice is signed, not after the problem appears.
Send the grade, the size and the quantity — you get a costed quotation within two working days.