Heat treatment manufacturers explain the advantages of vacuum carburizing heat treatment process.

Although the vacuum carburizing equipment and process have not appeared for a long time, due to a series of significant advantages and characteristics, the scope of application in production is rapidly expanding.

(1) It is easy to control the depth, carbon concentration, and concentration gradient (hardness gradient) of the carburized layer.

Heat treatment manufacturers believe that due to the physical and chemical reaction characteristics of the vacuum carburizing process, the process parameters of vacuum carburizing heat treatment can be determined simply by calculation or some relationship curves according to the technical conditions of the parts. Production practice shows that, especially for mass production, it is necessary to verify and correct the calculated process parameters by process experiments, which is very important for mass production of high-precision and important parts. Production practice has also shown that as long as the process parameters determined through process experiments are followed, very consistent carburizing results can be obtained from furnace to furnace—with good reproducibility.

(2) The surface quality of carburized parts is high.

The heat treatment plant believes that because the vacuum carburizing heat treatment is heating, soaking and diffusion after carburizing in a vacuum state, the parts do not have problems such as decarburization and black structure, and the surface is clean. In this way, the post-cleaning process can be omitted and the finishing process after the heat treatment can be facilitated.

(3) Vacuum carburized parts have high mechanical properties.

Heat treatment manufacturers believe that because the vacuum carburizing heat treatment parts have the characteristics of high surface quality (no decarburization, no oxidation), it has a very favorable impact on the stress state and fatigue strength of the surface layer.

(4) It has better carburizing effect on parts with blind holes, deep holes and narrow slits. For stainless steel, silicon-containing steel, etc., which are difficult to carburize by gas carburizing heat treatment, carburizing can be carried out smoothly by vacuum carburizing method.

(5) Thin, thick (up to 7mm) and high carbon concentration carburized layers can be obtained. A steep or gentle carbon concentration gradient can be obtained by making the time of the carburization period and the diffusion period different.

(6) High temperature carburizing heat treatment can be performed to shorten the carburizing time.

Heat treatment manufacturers believe that vacuum carburizing is developed on the basis of exploring the possibility of high temperature carburizing. The reason why high temperature carburizing is possible in a vacuum state is that the structure and component materials of modern continuous carburizing furnaces can already meet the requirements of high temperature carburizing.

High temperature carburizing heat treatment can significantly shorten the carburizing time. This is because at high carburizing temperatures, austenite has a higher solubility for carbon, and the carburizing gas used can fully supply activated carbon atoms. It is also because high temperature carburizing can significantly increase the diffusion rate of carbon in steel. In addition, the parts are heated in a vacuum state, resulting in degassing, removing oxides and other effects, thereby activating the surface of the parts and accelerating the absorption process of carbon atoms.

Under ordinary gas carburizing conditions, the carburizing furnace cannot withstand high temperatures for a long time. Therefore, high temperature carburizing tests with gas carburizing furnaces have been unsuccessful for many years.