Analysis and control of non-metallic inclusions in typical card clothing steel wire rod

Three kinds of typical card clothing steel hot rolled wire rods produced by three steel mills were selected. The density, size, type and distribution of inclusions were compared and analyzed by scanning electron microscope, energy spectrum analyzer and automatic inclusion analysis system. The transformation and formation sequence of inclusions during solidification were calculated by thermodynamic calculation software FactSage, and the formation rules of TiN and MnS were revealed. The results show that the clean steel production route was adopted for the card clothing steel from different manufacturers, and the total oxygen content was below 1.5×10^-5 （mass fraction）. The characteristics of inclusions were different due to the smelting process. The inclusions in the card clothing steel of the imported S steel plant were small, and the oxides were mostly Al₂O₃ composite oxides with high melting point and high elastic modulus. The content of TiN in domestic N steel plant was too high. The proportion of SiO₂ in the needle cloth steel of domestic G steel plant was reasonable, and the deformation ability was good, the melting point was low, the average size was below 3 μm, and the control effect was the best.