• PDF / 2,692,307 Bytes
• 12 Pages / 593.972 x 792 pts Page_size
• 2 Downloads / 205 Views

DOWNLOAD

REPORT

---

ION

AS an alloy element, titanium functions to improve the strength, corrosion resistance, nitrogen fixation, and deoxidation properties of the material in which it is used. It has been widely applied in both titanium-bearing stainless steel and titanium-bearing welding wire steel.[1–3] For example, splashing may be reduced by 30 to 50 pct during the welding process when titanium-bearing welding wire steel is used. Moreover, the toughness and strength of this material are significantly greater than those of welding wire steel without

ZHANLONG PIAO is with the School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, P.R. China. LIGUANG ZHU is with the Hebei High Quality Steel Continuous Casting Technology Innovation Center, Hebei University of Science and Technology, Shijiazhuang 050018, P.R. China. Contact e-mail: [email protected] XINGJUAN WANG, ZENGXUN LIU, BO WANG, PENGCHENG XIAO, and ZHIPENG YUAN are with the Hebei High Quality Steel Continuous Casting Technology Innovation Center, College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063000, P.R. China. Contact e-mail: [email protected] Manuscript submitted on April 28, 2020.

METALLURGICAL AND MATERIALS TRANSACTIONS B

titanium, owing to the grain refinement provided by Ti.[4,5] As a result, titanium-bearing welding wire steel has been widely utilized in welding processes for automobiles, ships, bridge engineering, and building engineering.[6,7] The slag-steel reaction generally makes the continuous casting of high Titanium steel difficult, which results in a decrease of the SiO2 content from the mold flux and an increase in the content of TiO2. This results in changes in the physicochemical properties of the resulting material, such as an increase in the viscosity and melting temperature. Additionally, the surface quality of the strand is damaged because of the deterioration of the physicochemical properties of the mold flux.[8] The equation of the slag-steel reaction in this case is as follows: ½Ti þ ðSiO2 Þ ¼ ½Si þ ðTiO2 Þ

½1

To reduce the negative effects of the slag-steel reaction, many researchers have focused on the design of a non-reactive mold flux for high Al steel, which is a CaO-Al2O3 slag system. The CaO-Al2O3 slag system avoids the slag-steel reaction by reducing the content of the SiO2 reactant, thereby effectively reducing the extent of this reaction for high Al steel.[9,10] However, the CaO-Al2O3 slag system with a low SiO2 content may not

be applied towards high titanium steel in terms of the slag-steel reaction because the content of the resultant TiO2 is zero, which will induce a forward reaction according to the Gibbs-free energy of the system. Fluorine, which acts as a fluxing agent, has been added to the CaO-Al2O3 slag system.[11,12] Although fluorine has the advantages of reducing the melting point, viscosity in this system, it also serves to corrode the casting facilities, contribute to environmental pollution, and endanger the health o