ROLE OF FRICTION IN ASYMMETRICAL ROLLING
DOI:
https://doi.org/10.20535/2305-9001.2013.67.37831Keywords:
asymmetrical rolling, metal powders, coefficient of friction, slipping friction, friction at restAbstract
Purpose. Methodology of estimation the friction coefficient is discussed relative to asymmetrical rolling for powders using rollers of different diameters that rotate with similar angle velocities.
Design/methodology/approach Experimental methods and analytical dependencies used for measuring the friction coefficient for various patterns of rolling are considered. The method of forward slip, the method of measurement of friction coefficient via the diagram of radial pressure upon the roll, and the method of roller-pin testing on standard friction machines are validated as useful for application to conditions of asymmetrical rolling on rollers of various diameters that rotate with similar angle velocities. A hypothetical curve of the friction coefficient variation at powder rolling is suggested that accounted for the presence of slipping friction and friction at rest. At the above pattern of asymmetrical rolling, the friction force of the smaller roller extrudes the metal out of the rolls within the lag zone, while in the zone of slippage on the delivery side, the friction force on the major roll shall depend on the rolling conditionsReferences
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