Different types of steel manufacturing can perform better for specific applications. Construction industry occupies more than 50% of the world steel demand.
Brief History of Steel: Iron as a construction material started in the fifteenth century Britain, manufacturing large quantities of iron. This has been developed into the modern steelmaking process with the invention of the air blown converter in 1856.
Hot Rolled Steel: Hot rolling refers to the mill process which you roll the steel at a temperature above its recrystallisation temperature, typically above five hundred degrees. Due to the high temperature, it becomes more malleable and can be easily shaped and can be produced in large quantity. It is then cooled in room temperature, which normalises it, to avoid the worry for stresses in the material arising when quenching or work-hardening. When the steel cools off, it will shrink non-uniformly, which gives slightly less control on the overall size and shape of a finished hot-rolled product. Its typically has a scaly surface finish. When the appearance of the material is a concern, several techniques are available, such as pickling, grinding, or sand-blasting.
Cold Rolled Steel: Cold rolling refers to steel that is pressed with the pressure of a roller at room temperature. Its has nearly 20% increase in strength comparing to hot rolled steel, but lower on ductility and toughness through strain hardening. It is through a lengthy process that steel shapes can be created. Cold-rolling steel allows for the creation of very precise shapes. Since the process is done in room temperature, it does not shrink as it cool. The surface is aesthetically pleasing. However, the applications of cold-rolled steel are limited to a couple of shapes - square, round, flat, and others. Cold rolled steel cannot be designed from methods given by BS 5950:Part 5.
Cast steel: Casting is the method of pouring liquid steel into a mold to produce solid metal objects. Typically used for complex or non-standard structural components.