Tees are not a typical steel section that mills produce. Almost all steel tees have to be created by splitting I-beams. Mills typically generate Tees up to 2.5” X 4.6 lbs/ft but once they become larger than that they have to be made by splitting I-beams. The web of the beam can be split by either a rotary shear or a torch to create two tees. This cut can be right down the middle to make two steel tees with equal depth or off-center to make tees with unequal depth lengths.
All beams of any shape contain residual stress. Residual stresses are those that remain in a solid material after the original causes of stress have been removed. Residual stresses can occur during a variety of mechanisms including temperature changes or structural changes. These residual stresses are released when the beam is cut. As a result, the two tees will actually repel and spring apart from each other, causing each piece to have a radius with the stem facing out. Some people would say it resembles a banana curve. On smaller sized tees, not only do the two tees take on this banana shape but they also will start to twist like a corkscrew. This makes the straightening process more difficult and time consuming.
If the desired Tee needs to be straightened, it can be done in two ways. The beam can be pressed in a cambering machine which restrains the steel section, while being pressed with one or two hydraulic cylinders. The second method would be to roll the beam in a section bender until it is straight. The second method tends to yield straighter tees.
Standard mill tolerance for straightening tees allows for 1/8th of an inch over 5 feet. However, experienced bender/roller companies with precise section rollers can cut that tolerance down dramatically. With section benders it is possible to double the mill tolerance and be able to hold a 1/8th inch tolerance over 10 feet. Some bender roller companies, if requested, can even hold tolerances of 1/8th of an inch on 30 feet or greater.
Once it has been straightened a steel tee can then be rolled or curved stem-up, stem-in or stem-out to very tight radii. Some of the common uses of rolled tees include stiffeners for tanks, component parts of equipment and roof supports.