12-20hi mills
DANIELI FRÖHLING‘s Split Block Mill Stands generally differ from the familiar monobloc or four column designs. In 1985 Danieli Fröhling supplied the world’s first Split Block – Twin Housing Cluster Mill with direct hydraulic roll gap adjustment and installations with this design principle have been supplied successfully to the industry since. The mill stands permit to achieve finish strip thickness of less than 0.01 mm.
A special design feature is the patented Double Bending Technology, applying roll bending to the inner and outer intermediate rolls. The number of flatness control elements is unique in a DANIELI FRÖHLING 20-High Mill with roll stack tilting, backup roller bearing shaft crown adjustment, bending of outer intermediate rolls, bending of inner intermediate rolls, and lateral shifting of inner intermediate rolls. The tilting of the roll stack is especially used on narrow mills for fast closed loop control of non-symmetrical or wedge type strip profiles. Those strip profiles are common for coils coming from slitting operation of wide strip. Other major advantages are the capability to use a large range of work roll diameters which can vary with a diameter factor of 1:2.5 and may address specific rolling targets in one single mill like Reduction and Skinpass Rolling. Furthermore, the design allows a large opening of roll gap, thanks to long stroke pass line roll gap and main cylinder adjustments. This facilitates threading and allows good accessibility to the roll gap. The direct hydraulic roll gap adjustment features high dynamic response, low hysteresis, high dynamic adjustment and hence, an improved thickness accuracy.