Method for preparing ultra-low-oxygen bearing steel cast ingot through vacuum induction smelting

Abstract

The invention discloses a method for preparing an ultra-low-oxygen bearing steel cast ingot through vacuum induction smelting. The method comprises the following steps that (1), raw materials, metal aluminum and a rare earth magnesium deoxidizing agent are prepared according to bearing steel components; (2), metal aluminum, a rare earth magnesium deoxidizer, volatile or oxidizable raw materials in the raw materials and a second part of carbon source are separately placed in a stock bin; the rest raw materials and a first part of carbon source are put into a crucible; (3), a vacuum induction furnace is started, vacuumizing is carried out, heating is carried out until the materials are melted, and argon is introduced (4), after the materials are completely molten, the second part of the carbon source is added into the crucible, and vacuumizing is carried out for vacuum deoxidation; (5), argon is introduced, the metal aluminum is added, and aluminum deoxidation is carried out; (6), the rare earth magnesium deoxidizer is put into the crucible for rare earth magnesium deoxidization; and (7), pouring is carried out. The three-step deoxidation enables the chemical reaction to be sufficient, reduces the content of oxygen and sulfur in steel, reduces the integral number of inclusions in the steel, and improves the solidification structure of the cast ingot.

Description

Technical field [0001] The present invention belongs to the technical field of metallurgy, in particular, it relates to a method for the preparation of ultra-low oxygen vacuum induction smelting bearing steel ingot. Background technique [0002] Bearings are critical to many important high-end device base member, the bearing service environment is very complex and often need to withstand the high contact stress, sliding wear and the alternating load, which bearing steel various properties, in particular the contact rolling fatigue life and stability of the proposed high requirements. [0003] In order to improve the life and stability of the bearing steel, a lot of research and found that the fatigue life and stability of harmful impurity elements in steel, especially steel bearing directly related to the oxygen content, thus Sanyo Special Steel Japan and Sweden are the OVAKA bearing steel oxygen content below 5ppm (ISIJ, 1985,71 (14), 1631-1638); and when the oxygen content in s...

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Problems solved by technology

[0004] Although the double-vacuum smelting process is beneficial to degassing and improving segregation, it lacks the refining slag to absorb and remove inclusions in the process, and the oxygen content at the end of the finished steel mainly depends on the oxygen content in the raw material. For example, "an extremely pure high-carbon chromium The smelting and production method of bearing steel" (CN2005100273940 / 2006) believes that only when the oxygen content in the vacuum induction smelting raw material does not exceed 7ppm, the oxygen content in the finished steel obtained by smelting will be lower than 3ppm, and the excessively high raw material cleanliness requirements It will inevitably increase the smelting cost of bearing steel; in addition, the size and distribution characteristics of inclusions in the steel cannot be effectively controlled

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