Narrow-hardenability high-temperature fine grain MnCr gear steel and preparation method thereof

Abstract

The invention discloses narrow-hardenability high-temperature fine grain MnCr gear steel. The narrow-hardenability high-temperature fine grained MnCr gear steel comprises the following components in percentage by weight: 0.19%-0.21% of C, 1.25%-1.35% of Mn, 0.20-0.30% of Si, 1.20%-1.30% of Cr, less than or equal to 0.020% of P, 0.010%-0.025% of S, 0.013%-0.02% of N, 0.034-0.050% of Al, less than or equal to 0.0015% of [O], less than or equal to 0.0002% of [H], and the balance iron and inevitable impurity elements. The invention further discloses a preparation method for the gear steel. The gear steel has the advantages of low cost, high-temperature fine grains, high purity, narrow hardenability, stable performance, and can ensure that the hardenability bandwidth of the steel is narrow, quality of the rolled surface of the steel is good, and the grains are small.

Description

technical field [0001] The invention relates to gear steel for automobile transmission gears, more specifically to a high-temperature fine-grained MnCr gear steel with narrow hardenability and a preparation method thereof. Background technique [0002] Gears are the basic parts of the machinery industry. It is subjected to various stresses such as variable load impact force, contact stress, pulsating bending stress and friction force for a long time during work, and the working environment is harsh. Therefore, the gear steel for manufacturing gears is required to have high strength, toughness, fatigue strength and durability. Abrasive. In recent years, with the development of the automobile industry, especially for cars, there are more stringent requirements for gears than other mechanical gears in terms of strength, toughness, wear resistance, fatigue resistance, and low noise. This puts forward higher requirements on the performance and quality of gear steel. [0003] H...

AI Technical Summary

Problems solved by technology

Its shortcoming is that the carburizing temperature that the gear steel can withstand is 930°C. Carburizing at a high temperature of 960-980°C will cause the grains of the steel to be too coarse and form mixed crystals, which will seriously deform the material and reduce the size of the workpiece. exceed the standard

[0007] The production methods of the above-mentioned prior art fine-grained gear steels are not conducive to simultaneously satisfying the requirements of narrow hardenability bandwidth, high surface quality and high carburizing temperature

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