Realize the heating without oxidation and decarburization: because the mould is heated in vacuum, the oxygen partial pressure of residual gas is very low, the surface is not oxidized or decarburized, and no toxic products are formed.
Small deformation and uniform hardness: because vacuum heating mainly relies on heat radiation under high temperature, low temperature convection is very weak, so the heating is slow, the temperature difference between the surface and the center of the workpiece is small, expansion and contraction are relatively uniform, resulting in small thermal stress, so as to reduce the final deformation of the workpiece.
Improve the plasticity and strength of the workpiece: the solid metal is heat treated under vacuum, and the surface has degassing effect, so as to improve its plasticity and strength.
Clean workpiece surface: the grease attached to these objects in vacuum belongs to common aliphatic group, which is carbon, hydrogen, oxygen compound, with high vapor pressure. When heated in vacuum, it is volatilized or decomposed, and then pumped out by vacuum pump to purify the workpiece surface.
On 2018-08-08 11:45:46
