Due to the existence of oxygen in the air, water vapor, carbon dioxide gas such as oxidation, general metal materials in the air heating furnace. These gases and metal oxidation is easy to make the heated metal oxide film or oxide skin appearance, completely out of the original metallic luster. At the same time, these gases react with the carbon in the metal, make its surface decarburization. If contains carbon monoxide and methane gas in furnace, still can make metal appearance carburization. For the chemical nature very lively TiZr and refractory metal WMoNbTa, air heating furnace, in addition to generate oxide, nitride, hydride, to absorb the gas and internal diffusion to metal, metal material performance deteriorated badly. The oxidation and decarbonization, carburization, breathe in, and even ills such as corrosion, controlled atmosphere or salt bath furnace heating furnace, sometimes hard to avoid. To solve this problem, typically artifacts leave allowance before heat treatment, after heat treatment in the process to get rid of oxidation and decarburization layer, etc.
Refers to the whole and part of heat treatment process under the vacuum state of countries could be divided into low, medium and high vacuum and high vacuum. At present most of the vacuum heat treatment furnace work vacuum degree in 1.33 ~ 1.3310 ˉ & sup3; Pa vacuum heat treatment furnace vacuum heat treatment of vacuum technology and heat treatment of the combination of the two professional integrated technology.
Such as quenching, annealing, tempering, carburizing, nitriding, vacuum heat treatment of almost all the heat treatment process can be realized. Quenching process of gas quenching, quenching oil can be realized, nitrate quenching, water quenching, etc., can also be vacuum brazing, sintering and surface disposal. Vacuum heat treatment furnace thermal efficiency is high, which can realize the rapid heating and cooling, which can realize no oxidation and decarburization, carburizing, can remove phosphorus crumbs on the surface of the workpiece, and has the effect such as degreasing degassing, so as to achieve appearance bright purifying effect. Generally speaking, the processed workpiece in the heating furnace is slow, and internal temperature difference is small, the thermal stress is small, so little deformation. Product qualified rate is high. Can reduce costs, have degassing effect, so as to improve the mechanical properties of the work and life. Good working environment, safe operation, no pollution and no pollution. Be processed workpiece no hydrogen embrittlement risk, to prevent the appearance of the titanium and refractory metal shell hydrogen embrittlement, stability and repeatability of vacuum heat treatment process. A series of advantages, the development of vacuum heat treatment equipment and technology is more and more attention and applied more and more widely.