Application of longitudinal cold rolling method in mass production of stepped shafts used in combustion engines

This paper presents little-known, innovative technology of cold rolling of stepped shafts. The method makes it possible to form and finish-up machine parts in the rolling process, which is associated with strengthening of material due to cold work. The author presents the results of investigations on the influence of the state of stress during cold plastic work on material's structure and its strength properties. The tests were carried out on shafts formed by longitudinal cold rolling (LCR), made of alloy steel, quenched and tempered before rolling to the hardness 34HRC. The influence of deformation degree on structural changes and increase of material strength is shown. Examples are given illustrating application of CLR technology in producing machine parts of shaft type designed for combustion engines.