Features of Structure and Property Formation of Rolled Coil for Wire Manufacture

Resumo

Results are given for research to develop scientifically based process solutions to improve quality characteristics of rolled coils cooled in a two-stage Stelmor line ensuring effective metal microstructure and processing properties for wire and wire products. An increase in welding rod ductility is achieved by limiting the steel’s strengthening element content, effective application of the boron to nitrogen ratio, and optimization of two-stage cooling, ensuring the formation of large ferrite grain size with rolling heat during isothermal soaking, thereby minimizing the formation of non-ductile structural components (bainite and martensite). For high-carbon wire rod used in the manufacture of concrete sleepers, it is necessary to achieve the fine pearlite structure of point 1 (GOST 8233–56) that is provided by alloying steel with boron, vanadium, and/or chromium, and also use of fan cooling. This structure is the optimum from the point of view of metal ductility and strength.