Comparison of the advantages of vacuum heat treatment and conventional heat treatment
Vacuum heat treatment, that is, the vacuum technology and heat treatment of two professional combination of integrated technology, refers to the heat treatment process in whole and in part is carried out in a vacuum state. Vacuum heat treatment can achieve almost all heat treatment processes, such as quenching, annealing, tempering, carburizing, nitriding, in the quenching process can achieve gas quenching, oil quenching, water quenching, etc. It has the following advantages compared with traditional heat treatment. 1, no oxidation, no decarburization, no carbonization of the workpiece internal and surface has a good protective effect. Oxidation makes the metal surface lose luster, surface roughness increases, precision decreases, and steel surface oxidation is often the root cause of quenching soft spots and quenching cracking, oxidation makes the steel part strength decreases, other mechanical properties decline. And decarburization refers to the phenomenon of steel in the heating of the surface carbon content is reduced. In general, the oxidation of steel decarburization at the same time, decarburization layer due to oxidation, carbon content reduction will significantly reduce the quenching hardness, wear resistance, and fatigue properties of steel, high-speed steel decarburization will reduce the red hardness. The vacuum heat treatment because the metal is heated under a certain vacuum, the workpiece to avoid contact with oxygen, the workpiece no oxidation, no decarburization, you can get a bright surface and better heat treatment quality, while in the vacuum state, there will be no reduction reaction, there will be no phenomenon of carbon increase. 2、Improve the overall mechanical properties, degas and promote the purification of metal surface. Vacuum has obvious degassing effect on liquid metal, and also has good exclusion effect on dissolved gas in solid metal. The most harmful gas in metal is hydrogen. When vacuum heating is used, the hydrogen in metals and alloys can be rapidly reduced to a minimum, eliminating hydrogen embrittlement, thus improving the plasticity, toughness and fatigue strength of the material and improving the overall mechanical properties of the workpiece. When metals and alloys are heated in vacuum, if the vacuum level is lower than the decomposition pressure of the corresponding oxide, this oxide will decompose and the free oxygen formed will be immediately discharged from the vacuum chamber, so that the metal surface quality, further improve, and even make the surface reach the activated state and play a purifying role. 3、Small deformation of the workpiece. In general, the workpiece being treated in the furnace by thermal radiation heating, the temperature difference between inside and outside is small, the thermal stress is small, thus determining the vacuum heat treatment process to deal with small deformation of the parts, while heating under vacuum and quenching under vacuum, automatically completed, avoiding the handling of the workpiece in the air in the hot state, reducing the artificial processing deformation, improve the product qualification rate. 4、It can reduce the volatility of the workpiece containing gold elements. Vacuum heat treatment can be heated and quenched under vacuum in a controlled atmosphere, thus reducing the volatility of gold elements in the workpiece and ensuring the quality of heat treatment of the workpiece. 5、The vacuum heat treatment furnace has high thermal efficiency, can achieve rapid temperature rise and fall, good stability and repeatability. Good working environment, safe operation, no pollution and public hazards.