A making group
Made by Rolling
Squeezed between rollers until it is a sheet, then sold by the sheet. One entry, the lightest material here and the one that traveled the furthest, which turns out to be the same sentence twice.
What rolling does that nothing else does
It covers area without weight.
That is the whole property, and it is the reason this group exists as a separate one rather than being folded into the others. A cut piece, a fired unit and a cast unit all weigh roughly what their volume implies. A rolled sheet weighs almost nothing for the area it covers, and every consequence in this group follows from that ratio.
A sheet can be carried a very long way for very little. It can be hung off the top of a wall that could not carry a masonry mass in the same position. It can be stamped into a shape that reads as heavy while being light. And it can be sold from a printed page by pattern number, because there is no reason to go and look at it first.
The grain in a sheet
Rolling leaves the material directional: it bends more willingly across the rolling direction than along it. Anybody who has folded metal knows this in the hands, and it matters here because everything in this group is made by bending. A pressed pattern has to be designed with the grain, not against it.
Two honest limits
The first is that this material fails invisibly. Galvanizing protects steel by corroding in its place, which works well and is finite; once the zinc is spent at a cut edge, the steel goes, and it goes on the inside of a hollow assembly where nothing shows. Sound paint over a section that has quietly lost its fixing is the characteristic result.
The second is that uniqueness is not on offer. The same dies supplied towns a long way apart, so a pressed pattern here is very likely on a front somewhere else. Reach is what this material sold.