For small, micro-precision bearings, the chemical composition of raw materials, the original organization, machining level, heat treatment process, and processing equipment are likely to greatly affect the bearing life.
The advantages of vacuum heat treatment
(1) Can achieve bright heat treatment. When the workpiece is heated at a pressure lower than atmospheric pressure, it does not touch the air and it won’t change surface. When the furnace is evacuated to 0.1 ~ 1Pa, the content of impurities in the workpiece can be reduced to 1.5ppm (1ppm = 0.0001%), so the workpiece achieves the purpose of cleaning bright quenching.
(2) Workpiece distortion after vacuum hardening. Such as the outer diameter of 65mm, wall thickness of 2mm 9Cr18 radial bearing rings, after the vacuum quenching, the ellipticity than ordinary heat treatment reduced to 1/8 ~ 1/9.
(3) With a degassing effect, improve the mechanical properties of the workpiece and the service life. (H2, N2, CO, etc.), resulting in micro-pores and hydrogen embrittlement, with vacuum technology can be the workpiece within the water and other impure gas removed, so that the workpiece surface is clean and bright, less prone to hydrogen brittle. And the surface quality is improved, the workpiece wear resistance, the service life can be increased by 30% to 120%.
(4) Can reduce the heat treatment after machining allowance. Vacuum heat treatment is not oxidative decarburization phenomenon, distortion is very small, so heat treatment can reduce the processing or even remove the machining.
(5) Decomposition of oxides. When the vacuum is lower than the decomposition pressure of the corresponding oxide of the metal or alloy, the oxide will decompose to form free oxygen discharge, so that the surface quality of the workpiece can be further improved and the surface of the workpiece can be activated.
(6) Clean operating environment , easy to operate, it is pollution-free, pollution-free cleaning heat treatment.