Connecting-rod dynamics of the primary drive in a cold-rolling mill

Mathieu–Hill equations are used to describe the parametric vibration of the connecting rod in the primary drive of a cold-rolling mill for pipe production. The Eins–Strett diagram is presented, and regions of stable connecting-rod operation are identified. Connecting-rod designs are proposed (on the basis of highstrength alloys), and the crank of the primary drive is modernized (with splitting of the crank gears). That stabilizes pipe production.