Abstract
The service life of work rolls can be substantially increased by substituting special wear-resistant sleeves for the conventional roll surface and a tough steel arbor for the roll core. In practice, the feasibility of such a structure is dependent on the method of securing the sleeves to the arbor. This thesis describes the design of a novel composite roll system which utilises the elastic properties of a pre-tensioned arbor to provide controlled axial and radial sleeve clamping. The elastic stresses and overall deformation behaviour of a typical design have been determined using 1/4 scale three-dimensional photoelastic models. This work was undertaken in the light of a preliminary study which revealed: (a) The possibility of component overstressing under static and dynamic loading. (b) A degree of uncertainty associated with clamping load distribution and interface contact conditions in the assembled roll. The photoelastic model tests identified arbor pre-tensioning, for sleeve assembly, as the most critical static loading condition. By introducing an undercut fillet radius at the arbor bore termination, the associated SCF was reduced from 14 to about 4. 5. The critical stresses in the modified design are below the levels which would cause low cycle fatigue failure. The effect of superimposing rolling load is not critical when compared with the mean stresses developed in the assembled roll. The roll assembly is shewn to behave as a monolithic structure under transverse bending. This feature, which has considerable significance when related to mill stiffness and product tolerance control, is not available in alternative composite roll systems. An original method for analysing SCF's in a composite assembly is described. Sleeve geometry is found to have a considerable effect on the flexural rigidity of the roll assembly. Modifications to sleeve and arbor design are recommended, and have been included in a proposed composite roll prototype.