Slag for controlling impurities of pipeline steel

Abstract

The invention discloses slag for controlling the impurities of pipeline steel. The slag comprises the following components in weight percentage: 50-62% of CaO, 3.2-6.0% of SiO2, 24-30% of Al2O3, 3-8% of CaF2, 3-6% of MgO, 0.3-2.0% of FeO+MnO, and the balance of unavoidable impurities; and the ratio of CaO / SiO2 is 9-16. The slag for controlling the impurities of the pipeline steel is the slag for refining a steel ladle, which has a high basicity, low aluminum oxide content, low oxidability and good fluidity; the slag can control the basicity of steel ladle slag and the content of the components including the Al2O3 and the like, and reduces the oxidability, so that the steel ladle slag has the functions of improving liquid steel cleanness and controlling the impurities in the steel; the desulfuration and the deoxygenation of the liquid steel, and the control of the impurities are realized; and the quality of the liquid steel is improved.

Description

technical field [0001] The invention relates to a molten slag for controlling inclusions in pipeline steel. Background technique [0002] Pipeline steel is a low carbon ultra-low sulfur steel. Due to the complex use environment of pipeline steel, pipeline steel used in different environments has different requirements for pipeline steel, including mechanical properties, HIC resistance, SCC resistance, etc. of pipeline steel, so for pipelines of different grades and different use environments Steel has different requirements for the cleanliness of steel and the control of inclusions. The non-metallic inclusions in the pipeline steel are deformed during the rolling process and form linear or long strips along the rolling direction, which leads to the anisotropy of the properties of the steel. At the same time, the non-metallic inclusions in the steel also cause hydrogen One of the main causes of cracks. Since hydrogen-induced cracking (HIC) is the main cause of pipeline ste...

AI Technical Summary

Problems solved by technology

[0010] At present, the composition of refining slag of pipeline steel fluctuates greatly, and its basicity is between 3 and 5, sometimes slightly higher, and the Al in slag 2 o 3 The composition is basically above 35%, SiO 2 The content of slag is sometimes as high as 15%. Such slag composition is not good for the control of sulfur content, total oxygen (T[O]) content and inclusions in steel.

[0011] Most of the existing technologies involve bearing steel, cord steel and other high-carbon series steels and ladle slag deoxidation processes, and a few use low-alkalinity slag control technology with a basicity of about 1.0, but mainly for cord steel The refining process is controlled, and the composition control of slag that does not belong to low-carbon and ultra-low-sulfur pipeline steel

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