In the process of ring rolling machining, due to the influence of various process factors, the actual size of the forging cannot be equal to the nominal size, and there will be deviations in both the height direction and the horizontal direction. Therefore, the allowable dimensional deviation range of forgings should be specified, which is necessary to control the working life of the forging die and the inspection of the forgings. The dimensional tolerance of annular forgings is asymmetrical, that is, the positive tolerance is larger than the negative tolerance, which is due to the fundamental reason for the deviation of the dimension affected by the height direction, and the dimensional change caused by the wear at the bottom of the groove and the indentation of the parting surface is secondary. The horizontal dimension tolerance is also a positive tolerance greater than the negative tolerance, which is to take into account the wear of the groove, the staggered displacement of the forging is an unavoidable phenomenon, and all belong to the influencing factors of increasing the size, and the negative tolerance refers to the lower limit of the size of the annular forging, which should not be too large, and the size of the positive tolerance will not lead to the scrapping of the ring forging, and the positive tolerance is large to stabilize the process and improve the service life of the forging die, so it is relaxed.
After the ring forging is processed by the ring rolling machine, a deep hardening layer can be obtained after hardenability quenching, and it can be hardened by using a mild quenching medium, and the quenching deformation cracking tendency is small in conventional quenching volume, low in abnormal deformation tendency, low in conventional quenching cracking sensitivity, insensitive to quenching temperature and workpiece shape, small relative loss of grindable grinding wheel, large amount of grinding, insensitive to grinding wheel quality and cooling conditions, and not easy to occur abrasion and grinding cracks.