IfRollerWhat about the fracture? It is easy to find the cause of the roll fracture.

In the practical application process, roll fracture is a common thing. So, do you know the specific reason why the roller breaks? Today, I will give you a detailed introduction.

1. When the rolling temperature is low, the rolling pressure becomes large, and the rolling force is greater than the critical strength of the roll, the fracture phenomenon will occur.

2. The amount of water is not enough to meet the roller body, resulting in stress concentration and fracture.

3. Improper selection of rollers. The roll selection of 850 rolling mill should be based on strength and toughness, supplemented by hardness and wear resistance. For example, cast iron rollers are prone to breakage.

4. Ductile fracture. The shape of the fracture of this kind of roller is mostly "mushroom head", and the roller body near the fracture is crushed.

5. Whether the motor speed is too large. GeneralRollerThere is a process of eliminating prestress, which is often overlooked. Take into account that sometimes rolls that do not roll steel will jam themselves.

6. Premature unpacking, excessive stress, resulting in fracture.

7. The cold mold is too thin and the cooling speed is too fast, resulting in stress fracture.

8. Centrifuge vibration, cold rail finish is not enough, resulting in the outer layer of fragmentation.

9. Severe turtle cracks on the surface of the cold die lead to shrinkage resistance, and tensile stress leads to cracks in the roll.

The roller bearing of the rolling mill is an important part of the rolling mill, which is characterized by large unit pressure and large working speed range, which makes the temperature of the bearing unstable, so the bearing should have a high load capacity. In the design process of rolling mill, how to choose the roller bearing correctly is a very important work.

The roller bearings used in the strip mill are mainly sliding bearings and rolling bearings.

Selection of 1. Rolling Bearings

1. Types of radial bearings

Rolling bearings have the advantages of low friction coefficient, high precision, easy product serialization and mass production. Therefore, the rolling bearings of the plate and strip rolling mill are mostly used.

(1) Compared with double-row centripetal spherical roller bearings and tapered roller bearings, under the same external dimensions, multi-row cylindrical roller bearings can withstand larger external loads, and their working speeds are much higher than before. Two. But can not bear the axial load. When using this kind of bearing, it is necessary to add a separate thrust bearing to bear the axial load, so that the multi-row cylindrical roller bearing can fully bear the radial load.

(2) Four-row tapered roller bearing Since the rollers of the four-row tapered roller bearing have an angle with the horizontal plane when installed, it can bear both radial load and axial load.

(3) Double-row centripetal spherical roller bearings Double-row centripetal spherical roller bearings should also have a certain angle with the horizontal plane during installation, which can bear radial load and small axial load. It has the characteristics of self-aligning.

Above isRollerThe relevant knowledge points are introduced.