Distribution of strains during metal drawing in shifted roller pairs

The article presents the results of the experimental study of the influence of strain ratio in roller pairs on metal spreading during drawing of the rectangular cross section wire. Previous studies showed that the stability of the free size of the rectangular cross section is defined by the correlation of the metal deformation ratio in roller pairs under other equal conditions, the least deviations of this size were recorded at a maximum value of metal spreading in the second roller pair. The total value of relative metal sinking which provides maximum metal spreading in the first roller pair at a given deformation value remains constant in all cases of drawing the wire made of 65G steel. The aim of the study was to check the specified regularity at roller drawing of other materials which were chosen for research, such as M1 copper and VT1-00 titanium alloy. A drawing die having 170 mm diameter rollers was used in the research. The technique of carrying out the research consisted in the fact that at fixed values of shell reduction in the first roller pair, the size of metal reduction in the second pair of rollers changed with a certain step. At each experiment step the side size of a ready rectangular metal section was fixed and formed by a free metal current in the second roller pair. Each experiment was repeated five times and the results were averaged. The received points helped to build the curves of the dependence of metal spreading in the second roller pair on the size of relative reduction in this roller pair for various values of relative reduction in the first roller pair. Results show that the maximum value of metal spreading in the second pair of rollers is observed at a certain total value of the draft characteristic for the particular material deformed by drawing. The obtained regularity of strain distribution in metal drawing with shifted roller pairs can be used in designing modes of such hardware products as bars, wire, and pipes with various sections.