Abstract: Cold ring rolling technology has the benefits of high utilization, high precision, excellent surface quality, long fatigue life, which is the advanced plastic processing technology of bearing ring. Cold rolling and quenching of bearing ring are two key links of cold rolling. The residual stress of bearing ring due to cold ring rolling and phase transformation by quenching will seriously affect geometric precision and microstructures and properties, so it is needed for effective treatment. In this thesis, steel GCr15 rings in cold rolled and quenched treated by magnetic is studied. The residual stress of cold-rolled bearing rings in magnetic treatment, conventional stress relief annealing, stress relief annealing combined with magnetic treatment and the residual stress of bearing rings in magnetic treatment, tempering, tempering combined with magnetic treatment after quenching have been tested. Experimental results reveal that magnetic treatment has the effects on the residual stress of bearing rings in cold rolled and quenched. The residual stress to the rings treated by stress relief annealing combined with magnetic treatment after cold rolling reduce the most, followed by conventional stress relief annealing, the worst effect is magnetic treatment. The most obvious effect of residual stress to the bearing rings is the way treated by tempering combined with magnetic treatment after quenching, followed by tempering, the worst effects is magnetic treatment. As a result, the way to magnetic treatment combined with conventional treatment methods after cold rolling and quenching of bearing rings can reduce the residual stress effectually. To reveal the mechanism action of the residual stress by magnetic treatment from the perspective of dislocation, the mechanism of Frank-Read source dislocation multiplication is introduced. The influence rule and the effect mechanism of residual stress for steel GCr15 during cold ring rolling-quenching on the performance of bearing ring have been revealed, which provides theories and technical basis for the control of residual stress for cold-rolled bearing rings.

Key words: magnetic treatment;GCr15 bearing rings;cold-rolled rings;quenching;residual stress