Grinding heat can cause high temperature failure reason analysis of tapered roller bearing

Grinding heat can cause high temperature failure reason analysis of tapered roller bearings, 1) Appearance under the action of transient high temperature oxide layer of steel appearance and oxygen in the air, rises into extremely thin ( 20～30nm） The iron oxide thin layer. Keep in mind oxide layer thickness and the appearance of grinding metamorphosis layer is the total thickness test results in corresponding relation. This clarify the thickness of oxide layer, is directly related to the grinding process is an important symbol of grinding quality. （ 2) Amorphous layer organization grinding the instantaneous high temperature parts arrived in molten state, appearance of molten metal molecular flow is evenly coated in appearance, and base metal cooling at breakneck speed, form a very thin layer of amorphous tissue layers. It has high hardness and toughness, but it's only about 10 nm, it is easy to be removed in the fine grinding process. （ 3) High temperature tempering layer of instantaneous high temperature can make the grinding area looks certain depth ( 10 ~ 100海里) Be heated to a temperature higher than the workpiece temperature tempering heat. In did not reach the austenitizing temperature conditions, with the progress of heated temperature, its appearance will produce one by one and the heating temperature corresponding to the organization transformation, or high temperature tempering tempering hardness also fall subsequently. The higher the heating temperature and hardness of the land is also increasingly fierce. （ 4) Transient high temperature quenching layer when the grinding area on the second floor outside the workpiece surface heating to the austenitizing temperature ( Ac1） Above, the layer of austenitizing organization after the cooling process, the quenching into martensite structure anew. Burn artifact, whoever has the secondary hardening second time hardening layer must be a hard degree is very low under the high temperature tempering layer. （ 5) Grinding crack secondary hardening burns will make the workpiece surface layer stress changes. Secondary hardening zone is in compression state, the high temperature data back to the fire area underneath there is a large tensile stress, the crack at the center of the central here it is possible to attack. Crack propagation along the original austenite grain boundary easily. Serious burns will cause the entire surface grinding is crack ( Formed a crack) Formed workpiece scrapped. In an article: the four conditions is high temperature resistant bearing damage or failure under the form of an essay: high temperature bearing common bearing failure modes and mechanism were reviewed