Surface carbonitriding treatment method for planet shaft for tractor axle

Abstract

The invention discloses a surface carbonitriding treatment method for a planet shaft for a tractor axle. The surface carbonitriding treatment method comprises the steps of infiltration-assisted pretreatment, carbonitriding treatment and quenching and tempering treatment. The infiltration-assisted pretreatment comprises steps of surface treatment, infiltration-assisted coating liquid preparation, drying and sintering; a carbonitriding agent used in carbonitriding is composed of sodium carbonate, barium carbonate, Mo3N2, sodium tetrafluoroborate, sodium chloride and potassium chloride according to the mass ratio of (30-46): (23-36): (28-33): (1-4): (5-9): (1-3). According to the planet shaft for the tractor axle obtained through the carbonitriding treatment method, the quenching hardness of the surface ranges from 59 HRC to 63 HRC, the quenching hardness of the R / 2 position ranges from 48 HRC to 51 HRC, and the quenching hardness of the core ranges from 28 HRC to 30 HRC; the surface of the tempered structure is S(back) 1-2 grade, R / 2 is S(back)1-2 grade, and the core part is 2-3 grade; and the fatigue life (under 90% of survival rate) is 60-65 million times.

Description

technical field [0001] The invention relates to a carbonitriding treatment method for the surface of a planet shaft used for a tractor axle, and belongs to the technical field of metal surface treatment. Background technique [0002] The axle planetary shaft is the driving component in the vehicle power transmission system. The power provided by the engine is transmitted to the gear and the end through the planetary shaft. It is one of the most important parts of the vehicle. The planetary shaft of the axle is subjected to complex forces during the driving process of the vehicle, and may be subject to alternating loads and impact loads in the form of bending, torsion, tension and compression at the same time, especially for agricultural vehicles such as tractors, where the driving environment may be mountainous hills and steep slopes. In the muddy work area of ​​the paddy field, in the soft soil of the plain, under these harsh road conditions, most of the tractors operate un...

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Problems solved by technology

The carbonitriding treatment process disclosed in this patent is only aimed at improving the surface hardness of the product, and cannot simultaneously improve the strength, toughness and fatigue resistance of the product.

[0006] Based on the above, it can be seen that for the 40Cr alloy steel commonly used in tractor axle planetary shafts, there is no better carbonitriding treatment process to meet the strict requirements of tractors, a special agricultural machinery, for planetary shafts. Therefore, a A carbonitriding heat treatment process for 40Cr alloy steel, which can simultaneously improve the strength, toughness and fatigue resistance of planetary shaft products, which plays a key role in improving product quality for tractor axle manufacturers

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