Smelting process for control of spring steel inclusions

Abstract

The invention discloses a smelting process for control of spring steel inclusions, wherein the smelting process includes the steps: 1) electric furnace primary smelting; 2) argon blowing; 3) LF refining; 4) VD furnace refining; and 5) continuous casting. In the electric furnace primary smelting steel-tapping process, an Si / Mn Al-free deoxidation process is adopted for pre-deoxidation, and at the same time, active lime, a compound agent and refining slag are adopted; in the earlier stage of the LF refining, an Si / Mn Al-free deoxidation process and active lime are adopted, and the furnace slag basicity is controlled at 1.5-2.5; in the middle stage of the LF refining, refined slag is added, followed by, the Si / Mn Al-free deoxidation process continues to be adopted, deoxidation and desulfuration continues to be carried out, and the furnace slag basicity is guaranteed to be controlled at 0.7-1.4; argon bottom blowing is carried out in the whole process of the LF refining. The Al-free deoxidation process and the low-basicity furnace slag desulfuration process are adopted and are combined with a specific deoxidizing agent, the inclusions in spring steel can be well controlled, and thus the anti-fatigue property of the spring steel is improved.

Description

technical field [0001] The invention relates to the field of metallurgy, in particular to a smelting process for controlling inclusions in spring steel. Background technique [0002] Spring steel is a special steel used to make springs and elastic parts. With the lightening and energy saving of vehicles, higher requirements are put forward for the weight of vehicle springs; the high speed and heavy load of railway passenger and freight cars greatly increase the working load of springs, which also puts forward higher requirements for the design stress of springs . Under high stress conditions, due to the existence of non-metallic inclusions, the continuity of the matrix is ​​destroyed, resulting in the inhomogeneity of the metal structure, which becomes the source of fatigue cracks, which reduces the mechanical properties of the metal, especially the fatigue limit of the metal, and eventually leads to the spring of the break. In 2006, the automobile brake spring fracture a...

AI Technical Summary

Problems solved by technology

Although the above-mentioned aluminum-free deoxidation process is adopted, the desulfurization process of high-basic slag can effectively reduce the sulfur content in steel, but it cannot control the plasticization of inclusions well.

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