New methods of steel ball rolling

The paper presents three new ball forming methods which have been developed at Lublin University of Technology, Poland. These methods include: cross-wedge rolling (CWR), multi-wedge cross rolling (MWCR), and cross rolling with upsetting (CRWU). The processes have been discussed using an example of a simultaneous forming of four balls with a diameter of 22 mm. The tools securing the forming processes of semi-finished balls are presented. Taking advantage of the FEM, the courses of rolling processes as well as distributions of temperature and strain in obtained products are shown. Conducted in laboratory conditions, the rolling tests have proven that the balls produced by the developed rolling methods meet the requirements for ball mill grinding media.