Heating method capable of reducing depth of decarburized layer of GCr15 bearing steel

Abstract

The invention discloses a heating method capable of reducing depth of a decarburized layer of GCr15 bearing steel. The heating method comprises the following steps of: preserving the heat of steel billets for 30 minutes at a temperature of 500-600 DEG C in a heat preserving furnace; feeding the steel billets into a step beam type heating furnace to heat in four stages, wherein the temperature at a pre-heating stage is 850-1020 DEG C, a temperature at a heating stage I is 1100-1190 DEG C, heating time of the heating stage I is greater than 35 minutes, a temperature at a heating stage II is 1180-1220 DEG C, a temperature at a uniform-heating stage I is 1180-1220 DEG C, a temperature at a uniform-heating stage II is 1170-1210 DEG C, and heating time from the heating stage II to the uniform-heating stage II is greater than 130 minutes; introducing oxygen gas in a heating process, wherein oxygen gas flow at the pre-heating stage is 80000-90000 m<3> / h, oxygen gas pressure at the pre-heating stage is 8-9 bar, oxygen gas flow at the uniform-heating stage is 140000-150000 m<3> / h, and oxygen gas pressure at the uniform-heating stage is 14-15 bar. The method effectively shortens the heating time, and reduces the depth of the decarburized layer.

Description

technical field [0001] The invention belongs to the technical field of metal smelting and processing, and relates to a heating method, in particular to a heating method for reducing the depth of decarburization layer of GCr15 bearing steel. Background technique [0002] During the rolling process of steel, the slab needs to be kept at high temperature for a long time in the heating furnace to make the temperature of the slab uniform and the segregated elements uniform, but with the extension of the heating temperature and holding time, the surface of the billet will eventually be oxidized and decarbonization. The decarburization layer on the steel surface will reduce the surface hardness and strength of GCr15 bearing steel, and has a very important impact on its fatigue life. In the relevant national technical standards, strict requirements are also put forward for the thickness of the decarburization layer of bearing steel. In order to Improve its wear resistance and fatig...

AI Technical Summary

Problems solved by technology

The thickness of the decarburized layer can be controlled to a certain extent by controlling the heating temperature and holding time, but the comprehensive mechanical properties of the finished product will be poor due to insufficient heating time; stage heating, the billet heating is slow, waste energy, and affect production efficiency; Positive pressure, weak oxidizing atmosphere, waste energy, make billet heating slowly, increase production cost