The commonly used roll materials and uses are shown in the table. The performance and quality of a roll generally depend on its chemical composition and method of manufacture and can be assessed by its organizational, physical and mechanical properties and the type of residual stress present within the roll (see Roll Inspection). The use effect of roll in rolling mill not only depends on the material and metallurgical quality of roll, but also depends on the use condition, roll design, operation and maintenance. Different types of rolling mill roll service conditions have great differences, resulting in the difference of the factors are: (1) rolling mill conditions. Such as rolling mill type, rolling mill and roll design, pass design, water cooling conditions and bearing types; (2) Rolling conditions, such as rolled varieties, specifications and deformation resistance, pressure and temperature systems, production requirements and operations, etc.; (3) Requirements on product quality and surface quality, etc.