State of the Art in the Control of Inclusions in Tire Cord Steels and Saw Wire Steels – A Review

Non-metallic inclusions in tire cord steels and saw wire steels often act as breakage source during cold drawing and standing process. In this work, the control of inclusions in tire cord steels and saw wire steels in the production process are extensively reviewed. On the one hand, the new perspectives on the problems left over in the past have been discussed comprehensively, include the new understanding of the origins of SiO₂-CaO-Al₂O₃ system inclusions, the new found of evolution of inclusions in cord steel and saw wire steel during rolling and drawing process, and the new understanding of controlling the plasticity of inclusions. On the other hand, the new approaches of controlling inclusions in tire cord steels and saw wire steels have also been discussed, include alkali oxides treatment, boron treatment, Mg treatment and cerium treatment. R₂O (R = K, Rb, Cs) containing refining slag can significantly improve the cleanliness of saw wire steels and saw wire steels. Adding alkali oxides, boron or Mg into molten steel can dramatically improve the deformability of inclusions through expanding the acreage of the region with low melting points. The basicity of top slag at the range of 1.1–1.2, and ωAl₂O₃ in top slag around 3 wt% in order to control the composition of inclusions in the region with low melting points when ZrO₂-based refractory be used to reduced the pure Al₂O₃ inclusions in tire cord steel. Finally, the unsolved problems are summarized.