ANALYSIS OF POSSIBLE WAYS TO INCREASE THE PRODUCTIVITY OF THE EQUIPMENT PRODUCTION LINE OF ROLLING SHOPS

Abstract

The article considers guillotine scissors as one of the main element of the equipment of production lines of rolling shops in the processing of rolled steels. With the optimal design of the scissors, from the point of view of reducing the cutting force, it is worth paying attention to the improvement of the cutting process. Three successive stages of bar cutting on guillotine shears are considered, which indicate that the "indentation" that is observed at the end of the cutting process is equal to the maximum cutting force and is determined by the value of the maximum shear stress during shear of the cut material and its cross-sectional area. The influence of the change in the initial geometry of the knife on the increase in the cutting force has been established and can reach up to 24%. Inclination of the knife equal to 6 degrees is considered as the optimal angle, further increase in the angle of inclination does not give a significant effect.

A detailed analysis of the cutting formula indicates that the temporary fracture resistance has a significant effect on the cutting force, the regulation of which is possible by preliminary heat treatment of the workpiece or its heating during cutting. From the obtained results of modeling the influence of the preheating temperature of the workpiece on the cutting force, it can be seen that heating the workpiece in some way plays a positive change in the direction of reducing the cutting force. A more detailed analysis of the obtained values in the form of a visual display of the dependence of the cutting force on the heating temperature shows that hardening occurs for all steel grades in a certain temperature range, that is the heat treatment mode that is used to impart the greatest rigidity to the steel. For low carbon steels, it leads to a slight increase in the cutting force, and for alloy steels it is a critical indicator of the increase in the maximum cutting force. In the case of heating billets from different steel grades, an individual approach should be used for each individual steel grade.