llows for mass production
Economical production
High workability
No to very little internal stress
Hot rolling is the preferred technology for the mass production of long steel products par excellence as it is typically more economical than cold-rolled steel. Furthermore, it allows the processed material to be formed and shaped with ease. Another major benefit is, that hot rolled steel is practically free from internal stresses, as the steel is cooled down gradually. Yet, concessions have to be made in terms of profile accuracy and surface finish of the hot-rolled profiles.
What is cold-rolled steel?
In contrast to hot rolling, in cold rolling, the rolled material is usually formed at room temperature and thus below the recrystallization temperature. When cold rolling profiles, a wire rod is used as the semi-finished product. The desired profile cross-section of the end product also determines the diameter of the wire. The process is mostly used for forming wide flat products such as sheet metal.
For particularly complex profile cross-sections, multiple rolling processes may be necessary. This results in the profiles having to be solution annealed before the following pass. The primary goal of cold rolling is to reduce the thickness of sheet metal. The material to be rolled has usually already undergone hot rolling.
Advantages of cold-rolled steel
High accuracy
Increased hardness
Increased strength
Excellent surface finish
Cold rolling can be used to produce very close-tolerance profiles. It is therefore an ideal production method for manufacturing small to medium-sized special profiles. As the metal is shaped at lower temperatures, cold-rolled steel offers an increased hardness of up to 20 % as well as improved yield and tensile strength. Furthermore, parts made of cold-rolled steel have a very smooth surface, free of any rust and scale.
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