Hot rolled steel comes with a scaly surface, slightly rounded edges and corners and the surface is non-oily. – additional treatments can create internal stress within the material this can cause unpredictable warping if the steel is not stress relieved prior to cutting, grinding, or welding. – fewer shapes available cold-rolled (sheets, box section shapes: CHS, SHS, RHS) – Tubes have better concentric uniformity and straightness. – bars are true and square and have well-defined edges and corners – accurate shape (consistent and straight) Hot rolled bars and tubes once cooled, are processed into what we call “cold finished” tubes and bars. But forms like bars or tubes are “drawn” not rolled. The first thing to know is that steel strip has several names, sometimes being referred to as sheet (because the strip is cut into sheets) or coil (as the strip. Technically, “cold rolled” applies only to sheets that undergo compression between rollers. The term “rolled” is often used just to describe a range of finishing processes such as turning, grinding, and polishing, each of which modifies existing hot rolled stock into a more refined product. The steel is processed further in cold reduction mills, where the material is cooled (at the room temperature) followed by forming the material by either press-braking or cold roll forming to achieve the desired shape. While hot rolled steel is heated then cooled, cold rolled steel is heated and cooled at the room temperature and then rolled after again. – rough texture on a surface, need to be removed and buffed before painting – dimensional imperfections caused by heating (expanding) and cooling down (shrink, warpage) – Most popular shapes are hot-rolled (UC, UB, SHS, RHS, PFC, flats etc.)
– Hot rolled steel is allowed to cool at room temperature and it’s free from internal stresses that can arise from quenching or work-hardening processes – Easier to make: heat it up, push through, cool down and that’s it! Hot rolled steel is commonly used when precise shapes and tolerances are not essential. The cooling down may cause the steel to shrink and therefore there is less control over the final size and shape. The whole process is done at high temperature and at the end is being cooled down. It starts from a piece of still billet which is heated up 1700 degrees Fahrenheit (926° Celsius) and then the steel is rolled through the mill into the particular shape. It has its source in a mill process involving rolling the steel at high temperature. Hot rolled steel is easier to make, to shape and form. Sheets can also be produced in cold rolled option but they are only available on special request.
Here’s what you need to know!Īll of ours UB, UC, PFC, RSA, flats are hot rolled whereas SHS, CHS, RHS that we provide are cold rolled structural steel. We’re often asked about the differences between hot rolled steel and cold rolled steel.