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. Addition of K2O in the form of K2CO3 in low amounts in refining slags is economically feasible and may be beneficial for the production of high cleanliness tire cord steel and saw wire steel. The influence of alkali oxides (especially for K2O, Rb2O, and Cs2O) on viscosity, density, fluidity, and structure of refining slags should be researched further.