The protection effect of vacuum heat treatment on the interior and surface of workpieces

The protection effect of vacuum heat treatment on the interior and surface of workpieces

Vacuum heat treatment is a new type of heat treatment technology combining vacuum technology and heat treatment technology. The vacuum environment of vacuum heat treatment refers to the atmosphere environment lower than one atmospheric pressure, including low vacuum, medium vacuum, high vacuum and ultra-high vacuum. Zhuhai vacuum heat treatment actually belongs to atmosphere controlled heat treatment.

Vacuum heat treatment is a comprehensive technology combining vacuum technology and heat treatment, which means that all and part of the heat treatment process are carried out in vacuum state. The vacuum heat treatment plant can realize almost all the heat treatment processes, such as quenching, annealing, tempering, carburizing, chromizing, nitriding. In the quenching process, it can realize air quenching, oil quenching, nitrate quenching, water quenching, etc. compared with the ordinary heat treatment, there is no oxidation, no decarburization, no carburization, which has a good protective effect on the internal and surface of the workpiece.

Oxidation makes the metal surface lose metallic luster, the surface roughness increases, and the accuracy decreases. Moreover, the oxide skin on the steel surface is often the source of quenching soft spot and quenching crack. Oxidation makes the strength of steel parts decrease, and other mechanical properties decrease. Decarburization refers to the phenomenon that the surface carbon content of steel decreases when it is heated.

Generally, the decarburization of steel is carried out at the same time. Due to the oxidation of decarburized layer, the reduction of carbon content will significantly reduce the quenching hardness, wear resistance and fatigue performance of steel, and the decarburization of high-speed steel will reduce the red hardness.
Because the metal is heated in a certain degree of vacuum, the work piece avoids contact with oxygen, there is no oxidation and decarburization of the work piece, so the bright surface and better heat treatment quality can be obtained. At the same time, in the vacuum state, there will be no reduction reaction and no carbon increase.