1. Ring radial rolling principle
According to the arrangement of the roll and the ring radial emulsion can be divided into single-guided roll vertical rolling and double-guided roll horizontal rolling; the rolling principle is shown in Figure 1. The figure shows the radial rolling of the ring on a single-guide roller vertical ring rolling machine. Drive roller for the active roller, under the action of the motor to do constant speed rotary movement, at the same time in the role of hydraulic or pneumatic devices to do straight-line feed movement; core roller and guide roller for the passive roller, in the ring friction under the action of the friction to do a passive rotary rolling movement. Under the action of the driving roll, the ring is rolled through the driving roll and the core roll to produce continuous local plastic deformation so that the wall thickness of the ring is reduced, the diameter is enlarged, and the cross-section profile is shaped. When the ring is deformed and the diameter is enlarged to a predetermined size after many revolutions of emulsification, the outer surface of the ring is contacted with the signal roll, the drive roll stops the linear feeding movement and returns, and the emulsification process of the ring is finished. During the rolling process, the guiding movement of the guide roller ensures the smooth rotation of the ring. According to the different precision of the ring to be rolled, the guide roller has a fixed guide roller and follows the guide roller in two forms. The diagram shows the radial rolling of a ring on a horizontal ring rolling machine with two guide rolls. Drive roller in the motor drive to do constant speed rotary emulsion movement, but no feed movement; core roller in the hydraulic or pneumatic device under the action of radial feed movement and follower rotary rolling movement; guide rollers through the hydraulic device from the two sides of the ring forgings to a certain force to hold the ring pieces, the two guide roller arms will be with the ring pieces of the increasing diameter and gradually open to ensure that the emulsification process is smooth.
Figure.1 Radial rolling basic principle diagram
1. drive roller; 2. guide roller; 3. core roller; 4. ring piece; 5. signal roller
2. Ring radial axial rolling principle
Figure 2 is the principle of radial-axial rolling of ring pieces. Compared with the horizontal ring rolling machine with double guide rolls in radial rolling, the movement of the drive roll, core roll and guide roll is the same. The difference is that the ring radial axial rolling increased a pair of cone rolls as axial rolls, the pair of cone rolls mounted on the axial frame; cone roll surface linear velocity is basically synchronized with the ring end face linear velocity, the upper face cone roll for downward feeding movement, the lower face cone roll does not move upward or downward, at the same time, the two cone rolls will be done with the increase in the diameter of the ring to move outward horizontally, to complete the axial rolling of the ring parts.
Figure.2 Diameter axial rolling basic principle diagram
1. drive roller; 2. guide roller; 3. core roller; 4. ring; 5. end roller
3. Basic process flow of ring rolling
The basic process flow of hot rolled ring parts is shown in Fig.3; take 42CrM0 material as an example. Firstly, the cylindrical billet is heated up to about 1150℃, upsetting, punching, and de-linking skin to get the ring blank. The ring blank is loaded on the radial-axial ring rolling machine for emulsion until it meets the size requirements.
Figure.3 The basic process flow diagram of hot rolled rings
Ring cold rolling and ring hot rolling of the basic principle of work are similar; the difference only lies in the cold rolled ring is rolled at room temperature on the ring and does not need to heat the ring, but needs to be cooled in the process. Ring cold rolled ring equipment roll arrangement of both vertical and horizontal. Vertical cold rolled ring equipment; for example, the principle is shown in Figure 4. The principle is similar to the single guide roll radial emulsion ring; the difference is that the core roll realizes the rolling feed movement. Since the cold rolling of rings allows the parts to be as close as possible to the finished product in shape and size, a measuring device is required on the ring cold rolling ring equipment to ensure the dimensional accuracy of the parts. In addition, there is a set of specialized guiding mechanisms so that the guide roll can grow with the ring diameter and movement and can ensure that there is a suitable force acting on the ring to ensure smooth rolling. At present, the ring cold rolled ring parts are still limited to parts with a diameter of 300mm or less.
On the diameter of less than 300mm parts, ring rolling process for the use of direct bar turning, pipe material direct turning or forging billet a hot rolling a turning and so on. Because of these methods of processing the parts of low economic value, they do not meet the requirements of modern social mass production; therefore, in recent years, a ring cold rolled ring process. For deep groove ball bearing rings, for example, the processing process shown in Figure 5, the process is: bar feeding heating to 1150 ℃ – upsetting a pre-form hole, a punch cutting bottom hole 780 ℃ annealing – turning blanks a cold rolled ring whole diameter.
Figure.4 Ring pieces of vertical cold rolled ring of the basic process flow diagram
1. drive roll; 2. guide roll; 3. core roll; 4. ring piece; 5. measuring roller
Figure.5 Deep groove ball cross-section ring parts processing process flow