Manufacturing method of blank of bearing steel rolling body for wind driven generator yawing pitch bearing

Abstract

The invention discloses a manufacturing method of a blank of a bearing steel rolling body for a wind driven generator yawing pitch bearing. The manufacturing method comprises the following steps that (a), a bearing steel bar are heated to 1000-1150 DEG C and fed into a hot header to be cut, upset and molded; (b), a molded product is cooled to 550-700 DEG C with a liquid medium, after the molded product is taken out of the liquid medium, the molded product continues to be subjected to blast cooling to 200-350 DEG C, and then stack cooling is conducted; (c), a product obtained in the step (b) is moved into a balling annealing furnace; and (d), a product obtained in the step (c) is cooled to 690-730 DEG C and subjected to isothermal balling, after heat preservation is conducted for 5-10 h, the product is cooled to under 620 DEG C at the speed of 25 DEG C / h or below, and the product is fetched out of the furnace and cooled in the air. The tempering resisting stability of the product is improved, impact toughness is greatly improved, and the contact fatigue life is greatly prolonged; and the level of network carbides can be controlled under the second level.

Description

technical field [0001] The invention relates to a method for manufacturing a rolling element blank, in particular to a method for manufacturing a bearing steel rolling element blank for a yaw variable pitch bearing of a wind power generator. Background technique [0002] Wind power is a renewable clean energy, and the country is gradually increasing the proportion of clean energy in total energy consumption. According to relevant data, the annual installed capacity in the world is about 30GW. At present, the power of commonly used wind turbines is 1.0-6MW, which are divided into two types: onshore and offshore wind turbines. The design life is maintenance-free within 20 years. Among them, the yaw bearing and the pitch bearing are the key components in the wind turbine. They work under harsh working conditions and must bear a large overturning moment, and the rolling elements in the bearings-steel balls are the key. To ensure the consistency of steel ball performance, the un...

AI Technical Summary

Problems solved by technology

To ensure the consistency of steel ball performance, the uniformity of structure, the reliability and safety of use, the traditional rolling body blanking process cannot meet the requirements

[0003] The steel balls used in yaw and pitch bearings are large steel balls with a diameter of 40 to 82.55 mm. The traditional billet making process has the following disadvantages: 1. Forging with an air hammer has large spherical errors, deep decarburization layers, and final forging. The temperature is not easy to control, the inner structure is uneven, the labor intensity of the workers is high, and the production efficiency is low; 2. Stamping with a punch, there is a process of cutting the ring belt, the material loss is large, the radial forging streamline is damaged, and the contact fatigue life is reduced; 3. Hot-rolling process. Although the billet produced by the hot-rolling process has no ring belt, the forging streamline is reasonable, and the production efficiency is also high, there is a Mannesmann effect in this process. If the control is not good, the core of the billet is prone to occur. Microcracks or loose structure, so steel balls that require high reliability in applications are not recommended to be billeted by hot rolling