Cord Plasticity Of Steel Inclusions Thermodynamic Calculations

Steel Cord for radial tires to enhance the use of skeleton, with a high-intensity, good toughness characteristics. The process of steel Cord Production is that pull-out of the filaments wire rod fromΦ5.5mm intoΦ0.15-0.38mm. This process make the length of the wire-fold increase from 1000 to 1400 times, Cross-sectional area reduce to 0.08% of the original, it drawing close to the limit of technology, and it requests the number of the process of pull-outing and partnership be broken in 100km can't beyond 1. So there are high demands on its purity, inclusion size, shape and the rod surface quality. It is one of the steel types of wire with high quality and difficult producing.In order to reduce the matrix damage of inclusions for continuous steel, we should make the steel cord generate plastic inclusions with low melting point and little deformed in hot rolled, be strict to control the content of [Als] and [O] and reduce the number of inclusions in steel.In order to achieve the above requirements, we should do something following through calculating:1) Be strict to control the form of inclusion in steel cord, to control it in the plastic region, final component of inclusions in low melting point region arround Ca plagioclase (CaO·Al2O3·2SiO2), false wollastonite (CaO·SiO2) as well as the adjacent manganese aluminum garnet (3MnO·Al2O3·3 SiO2);2) Make the content of total oxygen below 0.002% in steel, reduce the number of oxide inclusions;3) Make the content of [Als] below 0.0003% in steel, be sure there are not inclusions of pure Al2O3 and TiN.In this paper, through thermodynamic calculations and detailed discussions of the theory, we get the technology that off oxygen with Si-Mn and low-alkalinity refining. And research a balance experiment under the conditions of high temperature(1550℃) and liquid Steel with low alkalinity (CaO 25%～40%, SiO2 35%～55%, Al2O3 0%～20%). The results from the balance experiment is that: most inclusions in steel is the calcium silicate inclusions of which melting point is below 1400℃, the deformability is strong, the size is almost between 3-8μm.