Lippert frames

Ralph Cramden wrote:
Simply put there are two methods used to make a structural shape. Hot rolled or cold rolled. Specifically in relation to an H or I which are a complex shape, there are two ways to make them. Hot rolled is steel goes in one end of a plant, and an I or H comes out the other. Its then shipped to a fabricator who cuts it, drills it, fabricates it.

Great info. and analysis!

One thing I've noticed in the rolled beams is that in longer trailers, they aren't one continuous length. They're a couple of lengths with the ends butt welded together. It's done so well it's hard to see it and looks too good to be done by Lippert. Is there a maximum shipping length and it is actually done by Lippert or is it done by the supplier? These welds don't ever seem to be a problem and I would think are critical to be done properly. I've never seen or heard of a structural beam in a building not being one continuous length.

The 3-piece welded beams are usually on ultralite TTs and are easy to spot at an RV show or on a dealers lot by running a finger along the weld or looking it it. But just why do they use these beams? Are they lighter than an equivalent dimension rolled beam? I would expect a rolled beam would have a higher grade/strength for an equiv. dimension and maybe cost more per foot? But then the cost of welding 3 pieces of flat steel together to make a beam has to be costly and labor intensive. The 6" welded I-beams we had on a previous TT might as well have been made from rubber they flexed so much.

Cold rolled beams are hot rolled beams that undergo further processing and improves tolerances and appearance and would cost more so doubt they are used in any RV frames. Flat steel is hot rolled tho. and is what the welded beams would be made from (the finish is smoother on them). I don't think cold rolling improves the strength and any difference in strength would be from different grades of steel used.