First, understand the process steps of gear processing of bearing slewings. You must first understand the material of the blank and the processing conditions after forging. Secondly, check whether the blank has defects such as lamination or cracks. Measure the contour size of the blank shape, including the inner diameter and outer diameter of the blank, the height dimension and the calculation of the machining allowance. It can accurately estimate the number of cutting tools used for turning. The blank of the bearing slewing can be divided into two categories: normalizing treatment and quenching and tempering treatment.
1. Turning processing
(1) Rough turning
(2) Rough turning aging
(3) Fine tuning
(4) Forming precision turning
(5) The inner ring of the cross three-row roller slewing ring is specially treated to prevent the inner ring of the cross-three-row roller slewing ring from deforming after heat treatment. Turning must be performed in pairs, that is, the raceways are processed back to back. No cutting is performed before heat treatment and no cutting is performed after heat treatment.
(6) Finish turning after heating
2. Heat treatment
(1) Raceway surface quenching: The bearing slewing raceway surface is quenched at an intermediate frequency to ensure that the hardness is not less than 55HRC, the depth of the hardened layer is not less than 4 mm, and the width of the soft belt is less than 50 mm. The corresponding position is marked with "S".
(2) After heat treatment: the bearing slewing inner ring and outer ring need to be quenched at 200 degrees for 48 hours before leaving the furnace. To ensure the disappearance of internal stress and prevent subsequent cracks. After the slewing ring manufacturer has heat treated and tempered each batch of slewing ring bearings, magnetic particle inspection is required to prevent cracks.
3. Gear manufacturing
(1) Certain bearing slewings used under severe working conditions require surface hardening treatment, such as in the field of excavators, pile drivers, wooden grabs, graders and other working conditions. They have relatively large impact loads and require quenching on the surface.
(2) With the rapid development of Industry 4.0, bearing slewings are more and more widely used in the automation industry. In this application field, the accuracy of teeth is relatively high, and the minimum requirement is also 8-level accuracy.
(3) After the gear manufacturing process is completed, there are follow-up processes, such as fine turning, plane, drilling, track grinding and assembly, and then the bearing slewing can be delivered.