Method for improving surface strength of high-strength alloy transmission rod

Abstract

The invention provides a method for improving the surface strength of a high-strength alloy transmission rod. The two ends of the transmission rod are provided with splines. The surfaces of the splines are to-be-carbonitrided faces. The method includes the steps that protection is performed in advance, a non-carbonitrided face of the outer surface of the transmission rod is plated with copper, an inner hole of the transmission rod is filled with stuffing, and the two ends of the inner hole are plugged through copper plugs; the transmission rod is hung and the transmission rod is perpendicularly clamped and hung in a thermal treatment furnace; carbonitriding treatment is performed; and after carbonitriding is finished, the high-temperature transmission rod is put in a cooling medium for quenching treatment. A copper plating method and a hole plugging method are adopted for carbonitriding treatment, it can be guaranteed that the material strength and tenacity of the non-carbonitrided face are enough, and the deformability of the transmission rod is guaranteed. It can be guaranteed that the transmission rod is prevented from being deformed greatly in the radial direction of the transmission rod when perpendicularly hung. A carbonitriding method is adopted, the depth of a hardened layer or the hardness of a core can be guaranteed, the surface strength of the splines at the two ends of the transmission rod is improved, high-temperature quenching is directly performed after carbonitriding is performed, secondary heating is not needed, and the deformation of the transmission rod is reduced.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a method for improving the surface strength of a high-strength alloy steel transmission rod. Background technique [0002] Transmission rod parts are made of 16Cr3NiWMoVNbE alloy martensitic steel. The spline parts of the parts are required to have a hardened layer of 0.1 to 0.3 to improve strength and wear resistance (HR15N>88), and other parts are required to have a certain strength. and toughness. Due to the high degree of alloying of the base material, the parts are long rods with through holes (Φ28.4×Φ14×378mm), the heat treatment needs to control the deformation of the parts within 0.2, and it is difficult to meet the requirements of the carburized layer by carburizing or nitriding heat treatment. Depth and two hardness matching requirements. [0003] Carbonitriding is a chemical heat treatment process in which activated carbon and nitrogen atoms penetrate into ...

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Problems solved by technology

Due to the high degree of alloying of the base material, the parts are long rods with through holes (Φ28.4×Φ14×378mm), the heat treatment needs to control the deformation of the parts within 0.2, and it is difficult to meet the requirements of the carburized layer by carburizing or nitriding heat treatment. Depth and two hardness matching requirements

[0003] Carbonitriding is a chemical heat treatment process in which activated carbon and nitrogen atoms penetrate into the surface of the workpiece at the same time. It is a composite strengthening technology combining the two processes. The 16Cr3NiWMoVNbE material has a high alloy content and contains a large number of carbide-forming elements. The quenching temperature is much higher than Carbonitriding temperature, during the infiltration process, the active atoms on the surface of the workpiece are adsorbed faster. Using the traditional process method, a certain depth of infiltrated layer can be formed, but it cannot be directly quenched. It needs to be heated twice, and the deformation of the workpiece is large. It cannot meet the processing requirements of long rod parts; if carburizing technology is used, the depth of carburizing layer and surface hardness cannot be guaranteed at the same time; if nitriding technology is used, the workpiece needs to be pre-conditioned, after nitriding, the hardness of the core of the workpiece is low , can not meet the hardness requirement

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