I think we all know of Chinese bearing quality SKF bearings than the quality is much better, but we do not know, original SKF bearingsmanufacture have been taken into account at the time of bearing applications running speed as well as poor work environment, and so on, to produce such a high quality bearings.
SKF bearing grinding, grinding wheel and workpiece contact zone, spending a little bit of energy, a small amount of grinding heat, forming part of grinding zone instantly cool. Application of linear static heat source heat transfer practice formula, calculation or application of Red inside and instantly temperature thermocouple measurement method under test conditions can be inventions within the 0.1~0.001ms of grinding zone instantly the temperature can be as high as 1000~1500℃. This instantly at low temperature, sufficient to enable the task looks sure looks layer of low temperature oxidation occurs, non-crystalline, low-temperature tempering, quenching for the second time, or even burn crack a variety of changes.
The first factor is the surface oxide layer
Instantly the steel surface subjected to low temperature and oxygen in the air, rising into very thin (20~30nm) thin-layer iron oxides. It is worth focusing on oxide layer thickness and surface grinding metamorphosis total layer thickness of a correspondence between the consequences of the. This coherent explanation of oxidation layer thickness and grinding process indirectly are important marks of grinding quality.
Second factor is amorphous tissue layers
Instantly make appearance at low temperature of grinding zone when it reaches the melting conditions, melting of metal elements task-flow is evenly coated surface, metal cooling at an extremely fast rate and substrate, forming a very thin layer of amorphous organization. It has high hardness and toughness, but it just about 10nm, easily removed in fine grinding.
Third-largest factor was the low-temperature tempering
Instantly at low temperature to make the appearance of the grinding zone depth (10~100nm) by heating above the tempering temperature of heating the workpiece inside. Did not reach the temperature of austenitic condition, with the advances in heated temperature, heating temperature of its surface layer-by-layer will occur and must correspond to the tempering or tempered at low temperature tissue changes, landing the hardness. Heating temperature the higher the hardness of land have become increasingly fierce.
SKF bearings generally don't have to worry about quality problems, if SKF bearing most of the problems were caused by other external factors.
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