Ordering fabricated pipes directly from a machine or industrial shop is a way to secure appropriate pipes for work. Cold rolled pieces--sometimes called "cold drawn" or "cold finished"--are popular, but hot rolled pieces are another choice. Selecting one above the other requires knowledge of your needs, as well as the following considerations:
Hot rolled steel has only been through a singular process where it was rolled into the pipes you purchase. Cold rolled items are put through multiple processes from grinding to polishing; therefore, they're going to be more costly to the budget.
Obviously, increased processing will slow down your order. If you're having schedule or time constraints, cold drawn pieces might be pushed to the side in order for faster fabrication possibilities with hot rolled steel.
Because one of the processes involved in cold drawing is polishing, when you compare the various types you'll discover that cold drawn steel has a refined, finished look. If pipes will be exposed or used in a public way then this is a desirable feature, especially if you're unlikely to get other finishes done on the finished pieces. It's not that hot rolled pipes aren't attractive, but they can give off a rougher feel and appearance.
The processes that ultimately produce a cold steel piece aren't just for beauty. Tensile strength is greater for such pipes than if you use the ones that were created in a single hot rolling process. Therefore, cold processed steels are many times more appropriate for vehicles and commercial buildings where strength is paramount.
If your aim is to replace a few pipes in a larger system, hot rolled steel is easier to weld and can more easily join with other system pipes. This can reduce labor hours so that projects are wrapped up sooner.
If there are artistic considerations or odd spaces for which you're fabricating pipes, hot rolled steel will be an easier metal to bend and customize. You can do the same with cold drawn steel, but it requires a more expert hand and more time.
Both steel varieties will take further finishing. For example, even though already polished, you may ask for an anti-corrosive coating if a pipe will have ample exposure to water.
Pipe fabrication services staff will know all kinds of steel. They'll listen to your project specifications and issue suggestions, but these considerations and your own knowledge will be key to your decision.