Damage affecting IKO rolling mill bearing quality judgment

In IKO bearing grinding, grinding wheel and workpiece contact zone, a small amount of energy consumption, a small amount of grinding heat, forming part of the brake at low temperature in grinding. Application of linear stationary heat source heat transfer practice formula derivation, calculation, or red paint and thermocouple method measured experimental conditions of the brake temperature, can be invented in 0. 1 to 0. When grinding the brake temperature within 001 ms can be as high as 1000 ~ 1500 ℃. The brake at low temperature, enough to make sure depth task looks outside surface of low temperature oxidation, amorphous group and low temperature tempering, secondary hardening, and even burn cracking and other changes. The first factor is the appearance of oxidation layer brake at low temperature under the action of steel appearance and oxygen in the air, rises into extremely thin ( 20～30nm） The iron oxide thin layer. Notable is oxide layer thickness and appearance of grinding metamorphosis is the total thickness test results of corresponding relation. It explain the indirect coherent oxide layer thickness and grinding process, is an important mark of grinding quality. Second factor are crystalline state organizations layer when the grinding zone, brake parts appearance to molten state at low temperature, molten metal molecular flow is evenly coated in task appearance, and base metal cooling at breakneck speed, formed a very thin layer of amorphous tissue layers. It has high hardness and toughness, but it's only about 10 nm, very easily be removed in the fine grinding process. Third factor is the low temperature tempering layer when the grinding zone, brake temperature can make the appearance depth (certainly 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 be step by step and heating temperature should be absolutely to the organizational change, or cryogenic tempering tempering hardness also fall subsequently. The higher the heating temperature and hardness of the land is also increasingly fierce. Bearing judgment: bearing is available judgment, mainly considering bearing damage degree, mechanical properties, importance, and operating conditions, to the next overhaul period. If there are the following defects can't use, must be replaced new rolling mill bearing. Inner ring and outer ring, rolling element and cage on any one have crack or gap. 1, ring, rolling body fracture on any one. 2, rolling on the pavement, guard, rolling body CARDS have a significant injury. 3, keep wear significant or rivet significant relaxation. On page 4, raceway and rolling body rust, injury. On page 5, raceway and rolling body severe creasing and mark. 6, inner ring diameter or outer diameter surface has obvious creep. 7, due to the hot color change is obvious. 8, the rolling mill bearing grease sealed, sealing ring or dust cover breakage is obvious.