Bearing failure reason of grinding heat

Bearing failure reason of grinding heat in bearing grinding, grinding wheel and workpiece contact zone, consume large amounts of energy, produced a large number of grinding heat, local transient high temperature caused by grinding area. By using the theory of linear motion heat source heat transfer formula derivation, calculation or by the method of infrared ray and measured experiment under the condition of instantaneous temperature thermocouple method, can be found within 001 ms of 0, 1 or 0, grinding the instantaneous temperature up to 1000 ~ 1500 ℃. The instantaneous high temperature, which would have made certain depth on the surface of the work surface to produce high temperature oxidation, amorphous group, high temperature tempering, secondary hardening, and even burn cracking and other changes. 1, the surface oxide layer under the action of transient high temperature of the surface of the steel and the oxygen in the air, rises into extremely thin ( 20～30nm） The iron oxide thin layer. It is worth noting that the oxide layer thickness and surface grinding metamorphic layer is the total thickness test results in corresponding relation. This shows that the thickness of oxide layer, is directly related to the grinding process is an important symbol of grinding quality. 2, amorphous layer instantaneous high temperature parts surface grinding area to molten state when molten metal molecular flow is evenly coated to the work surface, and the matrix metal cooling at breakneck speed, formed a very thin layer of amorphous tissue layers. It has high hardness and toughness, but it is only about 10 nm, it is easy to be removed in the precision grinding processing. Three layer, high temperature tempering, grinding the instantaneous high temperature can make the surface of a certain depth ( 10 ~ 100海里) Be heated to a temperature higher than the workpiece temperature tempering heat. In the absence of austenitizing temperature reached, with the improvement of heated temperature, the surface will produce one by one and heating temperature corresponding to the organization transformation, or high temperature tempering tempering hardness. The higher the heating temperature and hardness of the decline is more severe. 4, second quenching layer when the grinding zone, instantaneous high temperature heat the workpiece surface layer to the austenitizing temperature ( Ac1） Above, the layer of austenitizing group in the subsequent cooling process, the quenching into martensite structure anew. Where the secondary hardening burns of workpiece, the second time hardening layer must be under very low temperature tempering hardness layer. 5 secondary hardening, grinding crack burns will make the workpiece surface layer stress changes. Secondary hardening zone is in compression state, the high temperature materials back to the fire area underneath there are the largest tensile stress, this is the place where the most likely to occur crack core. Crack is the most easily spread along the original austenite grain boundary. Serious burns can lead to crack of the grinding surface ( Formed a crack) Artifacts caused by scrapping. Above is the content of the bearing's official website, provided by the hope can help to you!