Cast steel roller can be divided into two categories: steel roller (0.4-1.4% carbon content) and semisteel roller (1.4-2.4 carbon content). Carbon content of steel roller is low; therefore the rigidity is low and its structure is composed of ferrite and pearlite. Along with increase of carbon content, the ferrite will be lessened and the content of the pearlite is increased. In order to enhance rigidity, alloy components such as Cr, Ni, Mo, or heat treatment can be carried out. With high tensile intensity and tenacity, the steel roller fits for breakdown mill or blooming mill with high temperature and great load, as well as underlay roller. If HS90 or above rigidity is gained, it can be used as cold rolling working roller if special heat treatment is needed.
Carbon content of semi-steel is between cast steel roller and cast iron roller and it is composed of pearlite, as well as certain content of carbonization; therefore its intensity is higher than cast steel roller and its rigidity is higher than common cast steel roller. Main characteristics of the semi-steel roller is that descent of the internal rigidity is low, therefore it fits for manufacturing deep-hole type roller and is widely used to rough rolling and finish rolling machine rack of profiled bar rolling mill, rough rolling and finish rolling frontal working roller for heat rolling strap steel tandem mill. If silica is added into the semi-steel roller, it will have high resistance to heat and cracking and has high tenacity. At the same time, it can be treated as breakdown mill of blooming mill, rough roller of large scale profiled bar, roller of breakdown tandem mill and vertical roller of steel tandem mill with heat rolling strap winning good rolling effect.
1、Basic structure of outer layer of the gold cast steel roller can be pearlite or bainite according to its chemical constitute and heat treatment process. The pearlite can be in form of slice or ball, or sorbite type which not only has good tenacity, but also good heat and cracking resistance. Especially the temper sorbite structure with phase also has good resistance to wear with good rolling effect.
　　Alloy cast steel roller has good tensile intensity and tenacity, certain degree of resistance to wear, heat and cracking, fit for breakdown and rolling of rolling mill and cogging roll of profiled bar roller mill.
　　2、 High-chrome Steel Roller
　　Outer side of high-chrome steel roller is made of high chrome steel （C:0.5-1.5%、Cr:8-15%）; Inner part is made of nodular cast iron with adoption of centrifugal, compound and teeming technique. It has good resistance to wear because outer layer of the roller is richer in chrome than high-chrome compound cast iron materials. In addition, as carbonization of basic structure in working layer of high chrome steel roller is low, hence it has good resistance to cracking. Therefore, high chrome steel roller is developing trend of materials for cogging roll of heating tandem mill at present.
3、Centrifugal compound HSS roller
　　HSS roller has high heat and cracking resistance, its high resistance to wear and rigidity can greatly prolong service life of the roller and enhance quality of the rolling materials, fit for finish rolling frontal worker rollers of heat-strap tandem mill.