Rolling bearings are a lot of produced mechanical parts, and the manufacturing precision requirements are very strict, and the level of professionalism is very high. Therefore, regarding the types of SKF bearings that are most easily bought, it should be more cost-effective to purchase than repairs, as long as the status is ridiculous. Next, I thought about the repair problem of SKF bearings, namely:
1) Many of the same type of SKF bearings used in large workplaces, the main way of failure is the wear of the rolling surface, fatigue or fretting, especially the damaged parts are mostly stuck to the frame or rolling body, while the ring or washer is still Have repair value;
(2) Certain types of SKF bearings that are really difficult to purchase, have to be repaired without spare parts after failure, especially SKF bearings;
(3) SKF bearings have minor damages, such as slight rust during storage, and slight fretting and abrasion during transportation. Such conditions are easily repaired and discarded.
(4) Large and extra large SKF bearings are on the verge of failure or have been damaged but the parts have not been seriously damaged, or precious SKF bearings must try to extend their useful life;
In addition to economics, the repair of SKF bearings also has its skills. This requires repairers to fully investigate the technical requirements of SKF bearing responses, and the structural, technological and data characteristics of SKF bearings and their parts, otherwise it is difficult It is guaranteed that the repair of SKF bearings will meet the requirements.
Economic benefits of SKF bearing repair:
Generally speaking, there are few types and large numbers of SKF bearings, the price of a single SKF bearing is high, or the structure of SKF bearings is simple. The larger the size, the lower the repair cost and the higher the economic benefit.
In addition, the operation status of SKF bearings is monitored, and the SKF bearings are effectively repaired on foot, and you can get twice the result with half the effort. Following a reasonable process, using efficient repair equipment and things, and obtaining the assistance of a professional SKF bearing factory will all contribute to improving economic efficiency.
Analysis of the cause of "black spots" on the surface of SKF bearing rings
It is reported in the literature that the "black spots" defects are caused by aggregated inclusions. Scanning electron microscope observation and energy spectrum analysis show that the "black spots" on the surface of SKF bearings are mainly due to pitting caused by chlorine, sodium, and potassium ions. Gathered inclusions. Chloride ions are brought in by pickling liquid during pickling. When part of the oxide film on the metal surface is damaged for some reason (may be scratches or bruises), it causes Cl- in the residual acid Invading, it reacts with the metal on the surface to become the anode, while the rest is the cathode, forming a micro battery.
As a result, the metal surface is corroded into a lot of corrosion pits, and the carbides containing Cr are not easily corroded and stored. The alkali generated by the cathode reaction around the etch pit promotes passivation and thus inhibits corrosion. Sodium and potassium ions are brought into the cooling fluid by the SKF bearing tube during the turning process, and its invasion accelerates the corrosion. In order to prevent the occurrence of similar phenomena, it is necessary to strictly prevent the workpiece from contacting with the medium of chlorine, sodium, potassium and other ions during the manufacturing process.
The remaining acid must be washed when pickling the surface oxide scale, and the cooling of the surface should be washed after turning. liquid. According to this measure, no similar situation occurred in the future production.
Through electron microscopy and energy spectrum analysis, it was found that the "black spots" defects were caused by pitting corrosion caused by the uncleaned pickling liquid during the processing, and then caused by the promotion of Na and K cations in the cooling liquid.
Maintenance of SKF bearings
SKF bearing maintenance, repair, and abnormal handling
In order to maintain the original performance of SKF bearings in good condition for as long as possible, maintenance and inspection are required to prevent accidents before they occur, ensure the reliability of operation, and improve productivity and economy. Maintenance is best performed regularly in accordance with the operating standards of the machine operating conditions. The contents include monitoring the operating status, replenishing or replacing lubricants, and regular disassembly inspections.
SKF bearing damage and countermeasures
Generally, if SKF bearings are used correctly, they can be used until they reach the fatigue life. But there will be accidents that damage it prematurely and cannot withstand the use. This early damage, as opposed to fatigue life, limits the use of qualities called failures or accidents. Many of them are caused by carelessness in installation, use, and lubrication, foreign objects invading from the outside, and insufficient research on the thermal effects of the shaft and casing.
About the damage status of SKF bearings, such as: the seizure of the ring flange of the roller bearing, as a cause, insufficient lubricant, unsuitability, defects in the oil supply and discharge structure, foreign matter intrusion, SKF bearing installation error, shaft If the deflection is too large, these reasons will also overlap.
Therefore, it is difficult to know the true cause of damage only by investigating SKF bearing damage. However, if you know the SKF bearing use machinery, conditions of use, the structure around the SKF bearing, and understand the situation before and after the accident, combined with the SKF bearing damage status and several reasons to investigate, you can prevent similar accidents from happening again.