Development of new roll pass designs for ball-rolling rolls with continuously variable parameters

Abstract

This article outlines modern approaches to the creation of roll passes for helical rolling mills for the production of grinding balls. The key feature is the roll design with continually varying parameters of its elements. Such elements include: flange width varying along the length of the roll; flange height, with a nonlinear function of flange rising; pitch of the helical groove which maintains constancy of the volume of the metal being deformed. Particular attention is paid to a new conceptual pass design for ball-rolling rolls with a variable groove depth, the prospects of which are connected with uniformity of reduction and the production of balls not only with the correct geometry, but also with a more homogeneous structure. The article shows functions of a continuously varying pitch of a helical groove of rolls with a constant and variable flange width, as well as with a variable depth of the groove. A practical test was conducted on ball-rolling rolls for production of balls with a nominal diameter 120 mm with continuously varying pitch. Experience has shown positive results both in reducing loads and in increasing the dimensional accuracy. © Published under licence by IOP Publishing Ltd.