Experimental testing of a new helical rolling technology

Abstract

Screw rolling is widely used in manufacturing seamless pipes and solid round products. In any operating helical rolling mill, deformation occurs under the influence of intrafocal axial compression (i.e., with backing), leading to significant transverse deformation. Consequently, metal shaping occurs under conditions of sign-variable radial deformation, which consumes a significant part of the power expended during rolling. As a result, the implementation of the rolling process under the influence of intrafocal axial extension (i.e., with tension) creates the most favorable conditions for the flow of metal in the deformation zone. The proposed technological solution opens up prospects for the use of swaging and rolling mills for screw rolling in producing continuous rolled products and specialized pipes in a wide range of sizes and grades. This article presents the results of the first experimental testing of a new helical rolling process performed on a mini-mill 14–40 under the conditions of the research and production center of the Department of Mechanical Engineering of the National University of Science and Technology “MISIS.” The experiment confirmed the operability of the new technology of helical rolling as a whole. The results obtained during experimental rolling showed that the specific power expended on the deformation of a unit volume, depending on the total reduction, was reduced by 25.4–37.3%, whereas the transverse deformation of the rolled billet was significantly reduced.