Comparison of main advantages and characteristics of low pressure vacuum carburizing furnace and traditional carburizing furnace

　　 In order to more fully grasp and understand, the main advantages and characteristics of low pressure vacuum carburizing furnace and traditional carburizing furnace are compared, see Table 3.

The temperature of the conventional carburizing process is affected by the performance of the furnace, and the maximum operating temperature is limited to 950 ° C. However, the improvement of the vacuum carburizing furnace technology can increase the maximum operating temperature to 1050 ° C. Since the carbon diffusion coefficient increases with the increase of temperature during carburization, the carburizing speed can be greatly improved, and the time for obtaining the same carburization depth is greatly shortened, which is advantageous for improving production efficiency and reducing production cost. The use of low pressure vacuum carburizing temperatures provides a prerequisite for increased production efficiency. For this reason, the use of a higher carburizing temperature can significantly increase the carburizing speed without affecting the mechanical properties of the part. A comparison of typical processes for conventional and vacuum carburizing is shown in Table 4.

The use of AISI8620 steel for the manufacture of heavy-duty transmission gears, the same temperature conventional carburizing and vacuum carburizing to achieve the same effective hardening layer depth test comparison is shown in Table 5.

It can be seen that in order to achieve the same depth of carburization hardening, not only vacuum carburization saves 74min compared with conventional carburizing (the production cycle is only 82% conventional), and the surface of the gear can still maintain the metallic color after being hardened by vacuum carburizing. No internal oxidation occurs, the deformation is greatly reduced, which saves the difficulty and time for the grinding process in the later stage of carburizing. The quality level and the reliability of use are doubled. It is understood that the gears for high-end gearboxes in the automotive industry must be required. Produced by low pressure vacuum carburizing technology). Some people have a carburizing time comparison of heavy-duty truck gears larger than the required carburizing depth of 1.60mm. The total carburizing time using low-pressure vacuum carburizing is only 385min, while the total carburizing time of the continuous controllable carburizing furnace takes 12h. The former produces The cycle is only 50% of the latter. This shows that under the premise of improving the quality of carburizing, the actual production cycle shortening is very obvious.

A large number of experimental data prove that the excellent results obtained by the low-pressure carburizing process technology have been accepted by the majority of users, especially in the case of poor deep carburizing quality which is difficult to solve by conventional carburizing (the occurrence of reticulated carbide in the long-term carburizing process). The actual carburizing time of vacuum carburizing is greatly reduced, and its superiority is very remarkable.

Some people have compared the case of vacuum carburizing with conventional carburizing to obtain the same carburized effective hardened layer. The results are shown in Table 6.

Compared with a large number of carburized gears, it is found that the high-hardening zone of the low-pressure vacuum carburizing layer can generally reach more than twice the conventional carburizing. This feature enables the gear to remain quite effective after carburizing and grinding. The hardened layer provides a guarantee. In addition, low-pressure vacuum carburizing avoids the generation of internal oxidation, and the quality of the layer is more excellent, which guarantees the reliability and high life of the gear.