204 Bearing Ring Vacuum Heat Treatment

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Vacuum quenching heat treatment has the advantages of safe operation, cleanness, no pollution and bright surface, no oxidation, no decarburization, small deformation, and high service life. Therefore, vacuum heat treatment technology has developed rapidly in recent years.

SIMUWU is a domestic manufacturer that provides high-quality vacuum furnace equipment and other supporting facilities for metal processing and other fields. Bearing rings are one of the most widely used parts in machinery manufacturing. This paper takes the 204 bearing ring made of GCr15 steel as an example to introduce the related vacuum heat treatment process.

Vacuum furnace heating takes six times longer than salt bath furnace heating compared to salt bath furnace heating. This is because the vacuum heating method only has thermal radiation, and the side of the workpiece facing the electric heating body heats up quickly, and the side facing away from the electric heating body heats up slowly. Therefore, in the selection of the vacuum quenching process, the heating temperature should be selected as far as possible at the lower limit of the quenching heating temperature, and the holding time should be appropriately extended to obtain a uniform quenched structure and reduce the deformation of the workpiece.

Process parameters:

Quenching heating temperature: 840℃±1℃

Push cycle: 1 basket / 30 minutes

Weight per basket (with basket): ~38kg

Heating chamber vacuum: >1×10-3torr

Quenching transfer time: 14~15 seconds

Nitrogen filling pressure before quenching: 380torr

Quenching oil temperature: 50℃

Oil furnace tempering process: 160℃ for 2 hours

After vacuum quenching, the surface of the workpiece is bright silver self-color, no oxidation, no decarburization, and even the thin oxide layer that has been discolored can be removed to make it bright again.

The VOGQ series vacuum oil quenching furnace produced by SIMUWU is an ideal product for this kind of processing. It has the advantages of good vacuum degree, high temperature uniformity and high heating accuracy. The company is equipped with an experienced team of engineers who can help producers to solve various problems in production.