Which caused the frequent damage of rolling mill bearings?

After analysis of effective data, the main forms of rolling mill bearing damage are fracture, wear and pitting.

Damage form one: Fracture: inner and outer ring fracture, rolling element rupture, cage fracture

The outer ring fracture is mainly caused by the excessive load and the insufficient bearing pressure.

In addition to the cyclic load, the inner ring is connected with the roll neck by the interference fit during installation. There is a positive tensile peripheral stress. As long as micro cracks are formed on the inner ring, they will rapidly spread and then cause fracture.

In addition to the above reasons, another reason for the fracture is that the oil and gas supply in the roller box is insufficient or interrupted, causing the bearing to heat up and then lock, and then causing damage to the inner and outer rings, the cage and the rolling elements.

Damage form two:  How is wear and pitting caused?

Most of the wear is caused by the relative rotation of the roll neck and the inner hole.

There are two main reasons for pitting: the bearing material is unqualified, caused by improper heat treatment. Foreign matter enters into the roller box, and pitting occurs during the running of the bearing.

In addition, due to improper operation, the copper bracket is deformed. When the roller enters the bearing housing, the ball rubs against the inner sleeve and then scratches the inner sleeve, so that the roller is inflexible during operation, causing bearing failure.

The height of the roll gap on both sides of the rolling mill is inconsistent, which causes the bearing to be stressed at a certain point due to uneven force during the running of the roll, thus causing bearing failure.

Configuration type of common rolling mill bearings

(1) Spherical roller bearings.  The configuration of the early rolling mill bearings on the rolling mill is different from the present. At that time, two sets of spherical roller bearings were mainly installed side by side on the same roller neck. This configuration basically meets the production conditions at that time, and the rolling speed can reach 600 rpm.

(2) Four-row cylindrical roller bearing + thrust bearing. The inner diameter of the cylindrical roller bearing is tightly matched with the roll neck, and it can bear radial force.  The cylindrical roller bearing has advantages of large load capacity, high limit speed, high precision, easy processing, low production cost, convenient installation and disassembly and the inner and outer rings can be separated.  The thrust bearing bears axial force, and the specific structure type can be selected according to the characteristics of the rolling mill. While for heavy-duty low-speed, we can equip with thrust roller bearings to withstand the thrust load with a small axial clearance. When the rolling speed is high, it is equipped with angular contact ball bearings so that speed limit is high and the axial clearance can be controlled. This type of bearing configuration not only has long bearing life, high reliability, but also has many advantages such as high precision and easy control of rolling products. Therefore, it is widely used in wire rod mills, sheet mills, foil mills, and support rolls for cold rolling mills and hot rolling mills.

(3). Four-row tapered roller bearings. The tapered roller bearings can withstand both radial and axial forces, and no need to configure thrust bearings. The inner diameter of the tapered roller bearing is loosely matched with the roll neck. It is very convenient to install and disassemble, but sometimes it will cause sliding creep due to the loose fit. Therefore, the inner diameter is often processed with a spiral oil groove. This type of configuration is widely used in the working roll of four-roll hot rolling mill and a cold rolling mill, and roll for blanking machine, steel beam rolling mill.

If you want to know more, please visit http://www.zys-bearings.com/ or send e-mail to zysdong@gmail.com. 

Angular contact ball bearings

Angular contact ball bearings: 7000C-type (α = 15 °), 7000AC type (α = 25 °) and 7000B (α = 40 °) of several types. This kind of bearing lock port on the outer ring, the inner and outer rings can not be separated in general, can withstand radial and axial joint load and axial load in one direction. Axial load capacity from the contact angle, the contact angle is larger, the ability to withstand high axial loads. This kind of Rolling mill bearing can limit the axial displacement in one direction shaft or housing.
Higher speed limit contact ball bearings can support radial load and axial load can also be subject to pure axial load, axial load capacity by the contact angle and the contact angle increases with the increase.

ZYS ball bearing With a high pressure oil pump through the nozzle hitting insert ball bearing

Oil lubrication method comprising :
1 drip lubrication
Drip lubrication oil rationing was needed for spherical roller thrust bearing components , usually every 3-8 seconds drip drop amount is appropriate , too much oil will cause bearing temperature increased.
2 cycle oil lubrication
The filtered oil pump feeding oil to the bearing member , through the bearing lubricant and then filtered after cooling to use. As the cycle oil can be taken away some heat , so cooling  insert ball bearing and therefore law applies to high speed bearing components.
3 oil bath lubrication
Oil bath lubrication is the most common method of lubrication , suitable for low- , medium-speed bearing lubrication , spherical roller thrust bearing part of the dip in the tank , oil from the rotation of the bearing parts brought up , and then back into the oil sump should be slightly lower than the center of the lowest rolling element .
4 jet lubrication
With a high pressure oil pump through the nozzle hitting the bearings , INA bearings in oil injected into the other end of the bearing into the tank through . When the Rolling mill bearing is rotating at high speed , the rolling body and the retainer are relatively high rotational speed of the surrounding air to form an air flow difficult with the general method of lubrication oil to the bearings , then the lubricant must be sprayed with high-pressure injection method to thrust spherical roller bearings , the position of the nozzle should be placed between the inner and maintaining aircraft center.
5 spray lubrication
With dry air formed by the spray mist mixed with oil , jet thrust spherical roller bearings, air bearings can effectively make INA cool and prevent intrusion of impurities . This method is suitable for high-speed, high-temperature lubrication of the bearing components.

portrait artist of the 11th Beijing International Automotive Exhibition

portrait artist of the 11th Beijing International Automotive Exhibition
Beijing  Bearings sales center news, May 2, 2010 , the 11th Beijing International Automotive Exhibition is the industry as " by far the world's biggest auto show next successfully concluded in a 10-day show in to " Imagine a Green Future " as the theme , demonstrating people, vehicles and nature in harmony ideal screen , providing a platform for high-quality display of green innovation as the world's top brand auto parts conglomerate -.  bearings company , NSK portrait artist of the 11th Beijing International Automotive Exhibition. classic booth design, top-notch products, professional Four-Row Cylindrical Roller Bearingtechnical explanation , showing the  for endless pursuit of high-quality products and excellent professionalism  employees , cited to the attention of many domestic and foreign Rolling mill bearing  manufacturers .
 Beijing Auto Show as China 's largest auto show, but with the development of China 's automobile market is becoming increasingly important , especially in the financial crisis , China 's auto market thriving, like the desert among a pool of water , which attracted all the world's cars internationally renowned manufacturers and parts manufacturers in the eye , auto parts suppliers such as : Bosch , DENSO, Magna ,Alpine, Bridgestone , Dunlop , Hankook , attended this show .  as a world -scale top-class auto parts conglomerate , which prides itself on high-quality products  Bearings Automotive World No. 1, EPS world-leading products , bearings distributor in China has and will continue to provide cheap and quality auto parts to China and the world's car manufacturers . After Beijing auto show experience with baptism ,  will continue to achieve a safe, comfortable and environment-friendly cars to boost social and development and make greater contributions to the automotive industry

Environmental protection is one of today's society a constant topic today

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