To build on your very important last point. Material handling procedure is something that I haven't seen mentioned here that is a very real issue too. Similar to agriculture or pharma where entire stocks can be thrown out if stored incorrectly, in many construction and manufacturing contexts your steel can be thrown out for not being stored correctly too (i.e. left at the port in the open for extended periods, or mixed with other metals). Not just steel, but lots of building products (like membranes) will usually be specd with how they should be stored before use.