White-layer-free nitriding method for gear ring in wind power speed increasing box

Abstract

The invention relates to a method for nitriding a gear ring in a wind power speed increasing box without a white layer, which comprises the following steps of: carrying out thermal refining on the gear ring in the wind power speed increasing box in advance, and then nitriding the gear ring in the wind power speed increasing box in a gas nitriding furnace at the temperature of 490-530 DEG C; the method is characterized in that the nitriding treatment comprises an emptying stage, a strong nitriding stage and a diffusion stage, in the emptying stage, N2 is firstly introduced to replace air in a furnace, and then NH3 is introduced to replace N2 in the furnace; nH3 and a small flow of cracked NH3 are introduced in the strong infiltration stage to obtain the required ammonia decomposition rate, and NH3 and a large flow of cracked NH3 are introduced in the diffusion stage to improve the ammonia decomposition rate. According to the method, under the condition that the gear ring in the wind power speed increasing box has good surface hardness after heat treatment, a white-layer-free nitride layer can be obtained on the surface at the same time, the brittleness of a workpiece is reduced, and therefore the abrasion resistance of the gear ring in the wind power speed increasing box can be effectively improved, and the service life of the gear ring in the wind power speed increasing box can be effectively prolonged.

Description

technical field [0001] The invention belongs to the technical field of metal heat treatment, and relates to a white layer-free nitriding method for an inner ring gear of a speed-up gearbox of a wind power generator. Background technique [0002] Nitriding is one of the common final heat treatment processes for the inner ring gear, the core component of the wind power gearbox, and other high-speed and heavy-duty wear-resistant parts. After nitriding, it has high surface hardness and wear resistance, high fatigue strength and high corrosion resistance. sex. At present, Cr-Mo-V alloy steel is widely used as the material of the inner ring gear at home and abroad. This material has good hardenability, high hardness after surface nitriding, and excellent wear resistance. In the existing gas nitriding process, due to the difficulty in selecting and controlling the nitrogen concentration on the surface, it is easy to form a white layer with a certain thickness during nitriding, whi...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the deficiencies of the prior art, the present invention provides a nitriding method for the inner ring gear of the wind power speed-up box without a white layer, which effectively solves the problem of the excessively thick and brittle white layer produced by the original nitriding process, thereby effectively improving wind power. The wear resistance and service life of the inner ring gear of the gearbox

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