Byelorussian Steel Works (BMZ) — Management Company of "Byelorussian Metallurgical Company" Holding, Steel Cord and Wire Products Research Centre (Zhlobin, Republic of Belarus):

А. V. Vedeneev, Yu. V. Feoktistov, B. A. Biriukov, V. I. Gritsaenko

E-mail: metsc@bmz.gomel.by

Difficulties related with run-out of central wire or core (for example, 1+6) during cutting of rubber-coated cloth are caused by the presence of internal compressive stresses in central elements of compact steel cord. These effects are linked with lay kinematics by the method of double twisting which are mainly used for the purposes of present-day production of steel cord. Double twisting of really and orderly arranged wires results in different layered shortenings of wire: it is maximum for external layer wires and it is zero for central wire. In order to offset compressive stresses, wires of internal layers are subjected to tensile forces, which are much higher than those applied to external wires. However, it is also essential to adjust for elastic residual stresses both for internal wires and external lay. Complex types of lay-related deformation result in different anchorage indirectly dependent behaviors of wires spiraled into steel cord. It is concluded that it's possible to use various technological methods to control migration tendency of steel cord central layers in the course of steel cord production and that the main reason for reduction of central structures anchorage is weakening of external lay wires under the effect of compressive stresses in wire. Additionally, squeezing moment of elastic come-back on steel cord central structures from external lay wires can be produced through obtainment of optimum difference in tensions and residual torques with the use of fine twisting in rotary unwinding.

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