Steel is available in thousands of different grades, each one being uniquely suited to a specific application. Although there are many grades of steel, there are only two primary steel types; hot rolled and cold rolled.
Hot rolled steel is typically used where dimensional tolerances or the aesthetic finish is not important. It is heated to very a high temperature and then shaped into a permanent form; railway tracks, skips, container trucks, etc. This type of steel is cheaper to produce than cold rolled steel, although grades and performance are still a factor in specification.
Cold rolled steel is firstly hot rolled, and then allowed to cool to normal temperatures. Once cold it is rolled into sheet or coils. It is this second cold roll process that makes the steel harder and stronger than hot rolled, and has a high-quality finished surface.
Cold rolled steel also have closer tolerances and are cut to precise gauges and widths. This uniformity means that they can repeatedly pass through the cold roll forming machinery with little adjustment, and allows manufacturers of formed products to offer standard product ranges.
Cold rolled steel for composite metal decking
Cold rolled steel is used right across the construction industry for a range of applications, most notably for roof decking, composite steel floor decking and wall panels.
In its pre-formed state, a single, flat sheet of steel is unable to support much weight, however, once it goes through a cold roll forming process, the folds act as stiffeners, increasing the strength of the sheet many times, allowing it to withstand stress without breaking.
Flat sheets and coils also come in varying thicknesses, so specifiers or designers will calculate the required load capacity and select the right gauge for the application.
The cold-forming yield for most steels range from 33 to 55 ksi but can be higher, depending on the required form and whether it requires connectors. The ratio of tensile to yield strength for cold-formed steels usually ranges from 1.2 to 1.8, but lower ratio steel can be used for specific applications.
High-performance steel decking
Lengths and strengths of a single deck, for example, will vary depending on the type of roll forming.
At AMDECK, the steel decking range features a unique embossment and other patented design properties that deliver exceptional structural performance and a very strong bond with concrete slab.
This high-performing steel deck is so reliably strong that it can allow some thinner gauge’s to be used, which can lead to a reduction in costs. It also means that longer lengths can be used too, without compromising strength.
AMDECK has two trapezoidal decks, AMDECK 60 and AMDECK 80 and one re-entrant deck, AMDECK 54. Each profile is available in 0.9mm or 1.2mm gauge, all at 600mm wide, making them lightweight and easy to handle.