Method for manufacturing carburization bearing steel for high speed train

Abstract

The invention discloses a method for manufacturing carburization bearing steel for a high speed train and aims to reduce contents of aluminum and titanium in steel to the minimum, reduce content of gas in steel and produce the ultrapure and ultra-fine grain carburization bearing steel with ultralow gas content through selecting specially-made high-purity ingot iron and pure metal charge and adopting vacuum induction + vacuum self-consuming smelting process. The method has the following advantages: the ultrapure carburization bearing steel with ultralow gas content is obtained, wherein content of hydrogen is not greater than 0.0001%, content of oxygen is not greater than 0.0006%, content of nitrogen is not greater than 0.0009%, content of fine series inclusions of A category, B category, C category and D category of nonmetallic inclusions is not greater than grade 1.0, content of Ds category is grade 0.5, and other types of inclusions are not contained; the grain size grade is grade 7.0 or above after the cementation process is adopted for treatment.

Description

technical field [0001] The invention belongs to the field of metal material manufacturing, and relates to a method for manufacturing carburized bearing steel for high-speed train sets, which is mainly applied to the production of bearing ring materials for axle boxes of train sets. Background technique [0002] At present, my country's high-speed railway is developing rapidly. It has built 20,000 kilometers of high-speed railway with world advanced level, and developed and produced Chinese standard EMUs with completely independent intellectual property rights. However, the high-carbon chromium bearing market for EMU axle boxes is monopolized by imported products. At present, the axle box bearings for EMUs produced by domestic OEMs are all imported from Europe and Japan. The main suppliers are SKF in Sweden, FAG in Germany, NTN in Japan and NSK in Japan. , foreign companies have imposed a strict technical blockade on China, and it is imminent to carry out independent research...

AI Technical Summary

Problems solved by technology

[0004] The publication number is CN 102226253 A, and the publication date is October 26, 2011. The patent titled "A Carburized Bearing Steel for High-speed Railway and Its Preparation Method" discloses a carburized bearing steel, which is characterized in that the chemical elements Percentage by weight: carbon: 0.18% to 0.24%, silicon not more than 0.10%, manganese not more than 0.10%, phosphorus not more than 0.01%, sulfur not more than 0.005%, chromium: 0.5% to 2.0%, nickel: 1.5% to 4.5% %, molybdenum: 0.3%~1.5%, niobium: 0.02%~0.04%, vanadium 0.3%~0.9%, the remainder is Fe and unavoidable impurities, [O]+[N+[H] content is 0.0020%~ 0.0040% and As+Sn+Ti+Sb+Pb not more than 0.060%, the bearing steel with chemical composition contained in this patent has not been officially used in China

At present, the carburized bearing steel mainly used in China is G20CrNi2Mo, and its smelting method is electric furnace + electroslag process. It does not require the content of residual elements and gases, but only the titanium content in the steel (titanium is not more than 0.005%). The smelted carburized bearing steel has an oxygen content of more than 0.0015%, a nitrogen content of more than 0.0050%, non-metallic inclusions of not less than 1.0, and a grain size of about 6, which cannot meet the current requirements. Requirements of high-speed railway for high-quality carburized bearing steel

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