Operation method for correct and effective adjustment of TIMKEN outer spherical bearing noise

TIMKEN bearings are precision parts and require a very cautious attitude when used. That is, the use of high-performance bearings can not achieve the expected performance if not used properly, and it is easy to damage the outer spherical bearings. Most of the bearings are damaged for many reasons - beyond the original estimated load, non-effective seals, too tight bearing clearance caused by too small bearing clearance. Any of these factors have their particular type of damage and leave a special mark of damage.

Therefore, inspection of damaged bearings can be found in most cases. In general, one-third of TIMKEN bearing damage is caused by fatigue damage, and the other third is due to poor lubrication. The other third is due to contaminants entering the outer spherical bearing or improperly installed.

Therefore, what we want to talk about is how to protect it and extend its service life. Who is unwilling to make the bearing wear-resistant and durable? Unless your nerves have problems (hehe), you should pay attention to the following matters when using bearings:

If the bearing is used improperly during operation, it will cause a series of problems, so we should pay attention to these problems in order to find the problem and solve the problem in time to ensure the normal use of the bearing. Under normal circumstances, the outer spherical bearing should pay attention to the following three major matters during operation.

First, check the condition of the running machine and monitor it to avoid equipment downtime.

Second, if the TIMKEN bearing is insufficiently lubricated or excessively lubricated, the lubricant contains a magazine, the load is too large, the outer spherical bearing is damaged, the gap is insufficient, and the high temperature friction generated by the oil seal is the same.

High temperatures often indicate that the bearing is in an abnormal condition. High temperatures are also detrimental to the lubricant in the bearing. Sometimes bearing overheating can be attributed to the bearing's lubricant. If the bearing is operated for longer than 125 degrees Celsius, it will reduce bearing life.

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Factors affecting bearing life and its control

China Bearing Network believes that the early failure modes of rolling bearings mainly include: cracking, plastic deformation, wear, corrosion and fatigue. Under normal conditions, it is mainly contact fatigue. Main intrinsic influencing factors: hardness, strength, toughness, wear resistance, corrosion resistance, internal stress state (outside service conditions).

1. Martensite in hardened steel
High carbon chromium steel original structure: granular pearlite
Quenching + low temperature tempering: quenching martensite M carbon content, which obviously affects the mechanical properties of steel
The carbon content of GCr15 steel quenching M is 0.5% to 0.56%, and the comprehensive mechanical properties with the strongest failure resistance can be obtained.
M: cryptocrystalline martensite, the measured carbon content is the average carbon content.

2. Retained austenite in hardened steel
High carbon chromium steel may contain 8% to 20% Ar (residual austenite) after normal quenching.
The Ar in the bearing parts has advantages and disadvantages, and the Ar content should be appropriate.
The hardness and contact fatigue life of Ar%↑ increase with the peak value, and then the beneficial effect of reducing Ar must be under the stable state of Ar. If it is spontaneously transformed into martensite, the toughness of steel will be drastically reduced. And embrittlement.
When the load of the bearing is small: Ar is slightly deformed, which reduces the stress peak, and strengthens the deformed Ar processing and stress-strain induced martensite transformation. The influence of the increased amount of Ar on the contact fatigue life is reduced. When the load is large: the large plastic deformation of Ar and the local body will locally cause stress concentration and break, thus reducing the life.

3. Undissolved carbides in hardened steel
The amount, morphology, size and distribution of undissolved carbides in hardened steel are affected by the austenitizing conditions due to the chemical composition of the steel and the original microstructure before quenching.
When the load (especially the carbide is non-spherical) and the matrix cause stress concentration and cracks, the toughness and fatigue resistance are lowered.
Quenching of undissolved carbides affects the properties of steel
Affects the carbon content and Ar content and distribution of quenched martensite, which has an additional effect on the properties of steel.
Excessive quenching of undissolved carbides is detrimental to the overall mechanical properties and failure resistance of the steel.
A small amount of undissolved carbides after quenching of the bearing steel is necessary for wear resistance. Fine grained cryptocrystalline martensite is required. The amount of undissolved carbides is small (small quantity), small (small size), and uniform (the sizes are very small, And evenly distributed), round (each carbide is spherical).
Properly reducing the carbon content of bearing steel is one of the ways to improve the service life of parts.

4. Residual stress after quenching and tempering
After quenching and low temperature tempering, the bearing parts still have large internal stress.
When the surface residual compressive stress increases, the fatigue strength increases (excessive residual stress may cause deformation of the part). When the residual internal stress is tensile stress, the fatigue strength is lowered.

5. Impurity content of steel
Impurities: non-metallic inclusions harmful elements (acid soluble), such as the higher the oxygen content, the more oxide inclusions, the influence of impurities in the steel on the mechanical properties and the failure resistance of the parts and the type, nature, quantity and size of the impurities and The shape is usually related to the reduction of toughness, plasticity and fatigue life. For bearing parts working under high stress, the oxygen content of the steel must be reduced. The MnS inclusions in the steel can be wrapped in an ellipsoid shape. Large oxide inclusions have little or even beneficial effect on fatigue life reduction.https://www.supplyforever.com/