Local Annealing Device and Annealing Method for Bearing Ring

Wide inner ring rolling bearing with fixed screw on inner ring, which is close to the end of groove of rolling bearing, has at least two axial external threaded holes. Fixed screw matched with external threaded holes can be used to fix the rolling bearing on the shaft, which is convenient for installation, maintenance and mainframe maintenance. It can be used in textiles, agricultural locomotives, and so on. Transportation and engineering machinery and equipment industries.

For high carbon steel roller bearing rings with holes, the holes on them are usually manufactured and processed before quenching and tempering treatment, and heat treated with steel parts (roller bearing rings) to HRC60 or above. In order to reduce the deformation of holes and external threads after quenching and tempering treatment and to prevent the application of rolling bearings, the whole process of tightening and fixing the screw is more intensive because of the position of the holes. At present, the screw teeth are fractured, and the cracks near the holes are serious, even the radial cracks around the rings occur. Generally, after the overall heat treatment of the steel parts, the parts near the holes are softened, and the common high frequency induction heating quenching is maintained.

At present, the annular electrothermal ring is used for quenching part of high frequency induction heating at the circumference of the radial annular cylinder to which the wire holes belong on the outer surface of the steel piece. Electromagnetic induction heating and heat transfer make the wire holes and the radial annular cylinder soft. When the heating temperature is high, the manufacturer can keep the holes and the vicinity of the return device softened by symmetrical quenching. But because of the high transmission effect of heat in high carbon steel, the softening near the holes will spread to the ring dovetail guide rail, resulting in the reduction of surface strength of rolling bearings, endangering the characteristics and service life of rolling bearings.

When the heating temperature is slightly lower, it is not easy to endanger the strength of dovetail guide rail, but the actual effect of softening at the screw hole is not ideal. Metallographic structure of the softened position is often uneven, the strength of the screw hole is different in the total length of the thin thickness of the steel piece, and the strength near the screw hole can not be reduced to the standard value. There are future applications. Potential risk of external thread cracking.