It is widely known that length and weight are the most basic specifications of steel products. And there is quite a number of commonly used terms for both length and weight in the steel industry. The importance of being aware of the appropriate usage of such terms in the right context is often understated, though it is very crucial for us to keep in mind how they differ from one another.

Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processing processes, heat treatment generally does not change the shape and overall chemical composition of the steel product, but changes the micro-structure inside the item or changes the chemical composition of the surface, thus endowing or improving the performance of the product. The purpose of metal heat treatment is to improve the intrinsic quality of the metal so that it has the required mechanical properties, physical properties and chemical properties. In addition to the reasonable selection of materials and various forming processes, heat treatment processes are often essential. Steel is the most widely used material in the mechanical industry. The micro-structure of steel is complex and can be controlled through heat treatment. Therefore, the heat treatment of steel is the main content of metal heat treatment.