The surface of steel (Steel) under the action of instantaneous high temperature (hyperthermia) interacts with oxygen in the air (AIR), and it rises to a very thin (20-30nm) thin layer of iron oxide (oxidation). It is worth noting that there is a corresponding relationship between the thickness of the oxide layer and the total thickness of the surface ground modified layer (TestMeasure). This shows that the thickness of the oxide layer is directly related to the grinding process (gōng y) and is an important indicator of grinding quality.

When the instantaneous high temperature (hyperthermia) of the grinding zone makes the surface of the workpiece reach the molten state (state), the molten metal molecule flow is uniformly (jūn yún) coated on the work surface, and the matrix metal is used extremely quickly. Speed cooling (cooling), forming a very thin layer of amorphous organization (organization). It has high hardness and toughness, but it is only about 10nm, which can be easily removed in precision grinding.

In the case of not reaching the austenitizing temperature, as the heated temperature increases, the surface layer will undergo a re-tempering or high-temperature tempering structural transformation corresponding to the heating temperature, and the hardness will decrease accordingly. The higher the heating temperature, the greater the decrease in hardness