NSK bearings contraction is also bearing problems of a precursor. Some would say that the thermal expansion and contraction is a normal phenomenon. At this time, we will have to see in the end in what circumstances bearing shrink it?
There is also a very important problem, NSK bearing part outline can be reduced to the speed of cooling the outer surface and to change the state of stress. We summarize bearing contraction mainly have a few questions.
1.NSK bearing workpiece water-cooled cooling speed up the direction of the principal stress and accelerate the cooling of the outer surface of the main. Prevent workpieces distortion.
2. Preliminary heat treatment should be carried out to the uneven thickness parts or the asymmetric pieces should take protective measures.
3. Workpiece prior to disposal, such as in the quenched state. NSK Bearings alloy steel annealing or tempering, and then shrink disposal; carbon and low alloy steels in 4c heating water or oil cooling, coupled with the hot water cold treatment.
The first contraction obvious, some quenching easy swell workpiece. The swell recovery factors; the second contraction pure contraction effect; should the total amount of shrinkage of the workpiece and then quenching will not swell the size tolerance.
Steel plastic. Contains less carbon and alloy steel. The thermal conductivity is small, the workpiece organizational structure. The coefficient of thermal expansion of austenite. Plastic austenitic steel contraction effect.
6 the workpiece main stress direction and the direction of the principal stress ratio. Contraction effect of the minimum when the ratio is close to ll.
7 contraction effect increases with the increase in the size, cross-section. The cross-sectional size of a direct impact on the size of the internal stress and workpiece plastic. But decreases as the size increases to a certain value, but a small part shrinkage effect is not obvious.
NSK Bearings is bearing fake and shoddy products, such bearings contraction normal contraction. Everyone in the purchase process, we must be careful.