Development trends of feeder tilting mechanism in hot pilgrim rolling

Pipe rolling units with pilgrim mills produce seamless hot-rolled pipes of a wide range of sizes and grades. The process of hot pilgrim rolling of pipes continues to be in demand at present, primarily due to its versatility, as well as the ability to obtain thick-walled pipes of considerable length. In the process of pilgrim rolling, it is necessary to perform sleeve canting (rotation around its axis) at an angle close to 900, which is provided by the canting mechanism of the feeder. Existing canting mechanisms on non-modernized feeders, including those in operation in Ukraine, do not ensure the stability of the canting angle of the sleeve in each pilgrim cycle of pilgrim rolling. As a result, the canting of the sleeve reaches 110÷1300, which leads to the formation of defects on the outer surface of the pipes, an increase in the transverse wall difference and, as a result, to increased metal consumption. In this work, the task is to analyze the known mechanisms of tilting the feeder and to propose an improved design of the tilting mechanism. For tilting the sleeve in the process of pilgrim rolling, the most widespread is the drill mechanism of tilting the feeder. In practice, the angle of tilting the sleeve, as a rule, exceeds the angle of tilting, kinematically determined by the pitch of the drill, by 200÷300. The reason for this is the accumulation of kinetic energy of rotation of the moving parts of the forgoller and the sleeve during the acceleration period and the lack of sufficient braking torque during the linear braking of these parts when the sleeve rolls into the rolls of the pilgrim mill. The possibility of slowing down (braking) the rotation by inertia in the braking phase of the moving parts of the forgoller during rolling by applying a braking torque to the plunger and using for this purpose the energy of the brake fluid, which is squeezed out of the braking chamber when the plunger ledge enters it, is considered. Tests conducted in production showed the need to propose improvements to the drill tilting mechanism of the feeder of the 5÷12" pipe rolling unit of PJSC "Interpipe Niko Tube". Based on the analysis of the operation of existing tilting mechanisms and research conducted in production conditions on a 5–12" pipe rolling unit, a feeder fore-holler with a separate tilting mechanism was proposed, which does not require radical reconstruction and allows you to adjust the tilting angle both during the sleeve seeding period and during continuous rolling. The proposed technical solutions for improving the tilting mechanism of the feeder expand the possibilities of choosing the most rational design.