440C stainless bearing steel grain refiner and preparation method thereof

Abstract

The invention relates to a 440C stainless bearing steel grain refiner and a preparation method thereof. The 440C stainless bearing steel grain refiner is prepared from Mg powder, Fe powder and nano C powder, and the mass ratio of the Fe powder to the Mg powder to the nano C powder is (93.9-94.1) to (4.9-5.1) to (0.9-1.1). According to the 440C stainless bearing steel grain refiner, adhesion of Mg in the pressed refiner is effectively avoided through the nano C powder, and meanwhile, Mg particles can be quickly separated from the blocky refiner through fine CO bubbles generated by reaction of the nano C powder and oxygen in molten steel in the steelmaking process, so that magnesium is uniformly distributed in the molten steel. Magnesium can be segregated at the grain boundary in the solidification process of the molten steel to fill up the surface defects of the grain boundary, so that the surface tension on a two-phase interface is reduced, and the nucleation speed is increased; and meanwhile, the grain boundary energy is reduced, the grain growth driving force is reduced, the grain growth is limited, and the properties such as strength and toughness of the 440C stainless bearing steel are improved.

Description

technical field [0001] The invention belongs to the technical field of metal material grain refinement, and relates to a grain refiner for 440C stainless bearing steel. Background technique [0002] 440C is a stainless bearing steel with a carbon content of 1.0% and a chromium content of 16% to 18%. It is mainly used to manufacture bearing parts working in corrosive environment and non-lubricated strong oxidizing atmosphere. 440C has good high-temperature dimensional stability, so it can also be used as a corrosion-resistant high-temperature bearing steel. In addition, it can also be used to make high-quality knives, such as medical scalpels, scissors, etc. Bearings are under great pressure and friction during work, so 440C bearing steel is required to have high and uniform hardness and wear resistance, as well as high elastic limit. The uniformity of the chemical composition of the bearing steel, the content and distribution of non-metallic inclusions, and the distributi...

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Problems solved by technology

Under such high temperature conditions, it will not only consume a lot of energy to raise the temperature, but also inevitably oxidize the raw materials, resulting in a certain loss

In addition, at the temperature of steelmaking, magnesium is very easy to gasify and quickly floats to the surface of molten steel, and it is difficult to play its role in refining grains.

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