Forming of properties complex of copper wire by the method of combined deformation by torsion and tension

Abstract

The object of research is the mechanical properties of copper wire M1 for electrical applications, subjected to combined torsional deformation with tensile tension. One of the most problematic aspects in the manufacturing of such a wire is its fracture during processing due to low strength and ductility. DSTU EN 13602:2010 regulates the ultimate tensile strength, relative elongation, the number of bends before fracture and the number of twists until failure. To increase the service life of the product it is necessary to increase strength and plastic properties. The methods of influence on the material by combined plastic tensile deformation with tensile was used in the study, the mechanical characteristics (ultimate tensile strength, true deformation before failure, relative elongation, relative reduction in area) and electrical conductivity were determined. Statistical analysis tools were used for modeling and graphical displaying of data. The proposed approach allows to select the modes of combined torsional deformation with tensile, providing the optimal combination of tensile strength and relative narrowing of M1 grade copper wire. Under certain modes of such deformation, with increasing degree of deformation, it is possible to increase the strength characteristics and at the same time obtain high values of plasticity. The obtained results of approbation of different combined deformation modes allow to consider it an effective tool for achieving high values of true rapture stress and ultimate deformation in order to improve the service characteristics of the deformed wire. It is shown that relaxation processes occur during such treatment, which leads to a decrease in stresses and a sharp increase in plastic characteristics. Clarification of the mechanisms of the characteristics formation allows to control the features of the structure and, accordingly, the level of mechanical properties to obtain a wire that combines high strength with high toughness. This makes it possible to develop deformation modes to obtain copper wire with special properties depending on customer requirements, for example: strong wire with low electrical resistance.