A method for eliminating irregular vibration marks on the surface of high carbon steel billets

Abstract

The invention relates to a method for eliminating irregular vibration marks of a high-carbon steel billet surface. Under the premise that original continuous casting process parameters are not changed, physical and chemical parameters of casting powder are reasonably and accurately selected, the quaternary alkalinity of crystallizer casting powder, namely R{w(CaO)+w(MgO)} / {w(SiO2)+w(Al2O3)}, is 0.64-0.70; the melting temperature Tm (DEG C) of the casting powder and the lowest liquidus temperature T1(DEG C) of casting steel types meet a relationship that Tm is equal to or larger than T1-450, and equal to or smaller than T1-420; the viscosity eta (Pa.s. 1300DEG C) of the casting powder and the casting speed v (m / min) meet the relationship of eta= 0.4 / v + 0.02; and besides, the sinusoidal vibration parameters of a crystallizer are reasonably and accurately set, the vibration frequency f (times / min) and the casting speed v (m / min) of the crystallizer meet the relationship of f=-16v<2>+23v+220, and the amplitude s (mm) and the casting speed v (m / min) of the crystallizer meet the relationship of S=-0.8v<2>+2v+3.8.Through the adoption of the production method disclosed by the invention, the consumption quantity of the high-carbon steel casting powder can be stably and reasonably controlled, the lubricating effect between casting blank and the crystallizer is guaranteed, the irregular marks of the high-carbon steel billet surface are eliminated, the surface quality of the casting blank is stably controlled, and the quality of finished products is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy. Specifically, it relates to a method for eliminating irregular vibration marks on the surface of a high-carbon steel billet. Background technique [0002] Vibration marks are lateral wrinkles with a certain depth formed on the surface of the slab under the periodic vibration of the mold. Generally, the regular vibration marks belong to the normal surface morphology of the continuous casting slab and will not affect the quality of the final product. However, disordered and abnormal vibration marks may increase the probability of surface cracks and slag inclusion defects, and make it difficult to roll together in the subsequent rolling process, resulting in the rejection of the rolled product. [0003] As a kind of high-quality carbon steel, high-carbon steel has a wide range of uses in national production. After proper heat treatment or cold drawing hardening, it has high strength and hardnes...

AI Technical Summary

Problems solved by technology

Adjusting the continuous casting process parameters is mainly to reduce the casting speed to achieve the purpose of increasing the consumption of mold slag. However, excessively reducing the casting speed will reduce the production efficiency of the continuous casting machine and affect the rhythm of the entire production scheduling. Practical meaning

Optimizing the performance of mold flux is mainly to select reasonable mold flux physical and chemical parameters, including mold flux viscosity, melting temperature and alkalinity, etc. However, in the actual production process, with the casting steel type, section, continuous casting process parameters Changes in mold flux viscosity and melting temperature are difficult to meet the changing production requirements. They are often selected based on experience without good applicability and stability. In addition, the basicity of mold flux is generally expressed by binary basicity, namely w(CaO) / w(SiO 2 ), which often ignores the influence of other main components in the mold flux, and cannot accurately describe the properties of the mold flux

Improving the vibration parameters of the mold is mainly to adjust the appropriate vibration frequency and amplitude. Generally, the sinusoidal vibration frequency and amplitude of the mold have a positive linear relationship with the casting speed, and the vibration frequency and amplitude are the increasing functions of the casting speed. It is a decreasing function of casting speed and vibration frequency. The maximum friction force between the casting slab and the mold is an increasing function of the vibration speed of the mold and the casting speed. If the casting speed increases, the vibration frequency and vibration speed will also increase, which will further Reduce the consumption of mold slag, increase the friction between the billet and the mold, and lead to further deterioration of the lubrication effect between the billet shell and the mold