Cold Rolled Steel is room temperature coil steel that has been rolled into tube form. The seam that completes the tube is joined by electric resistance welding (ERW). CREW is larger tubing that is used during the DOM process.
C1026
C1026 is very similar to C1020. They are both low-tensile carbon iron. And, both are primarily for manufacturing DOM tubing.
ERW
Electric Resistance Welded pipe or tubing. ERW is used broadly in engineered applications as well as less tolerance uses like fencing, and tents. It is also used as a blank during the DOM tubing process.
DOM
Drawn Over Mandrel is the process of which steel tube is pulled through a die in order to reduce its size.