Influence of the Vacuum Heat Treatment Process on the Quality of Ring Die

The overall quenching of the feed pelletizer ring mold generally refers to the heat treatment using an electric furnace or a salt bath furnace in an atmospheric environment. But in the past 20 years, more and more foreign feed machinery manufacturers have begun to use a vacuum furnace to quench the ring die. This heat treatment method is called vacuum gas quenching. That is, under a certain degree of vacuum, the ring mold placed in a closed vacuum furnace is heated above the austenitizing temperature, and then it is quickly gas-quenched with high-pressure, high-purity cooling gas. Compared with the traditional overall quenching, this vacuum heat treatment technology has the following advantages: the workpiece deformation is small; the metal surface after heat treatment is very smooth, no oxidation, corrosion, decarburization or carbon increase occurs; especially the ring mold hole finish Vacuum gas quenching basically does not reduce, which is essential to ensure the production of pellet feed. In addition, the vacuum heat treatment furnace is widely used, and it is energy-saving, safe and reliable, non-polluting, and easy to realize automatic operation.

Selection of ring die vacuum heat treatment equipment
Vacuum heat treatment furnace is a large heat treatment equipment used for vacuum gas quenching of ring die. When selecting a vacuum heat treatment furnace, feed machinery manufacturers should consider the following main factors: the type of vacuum furnace (vertical or horizontal), the size of the vacuum chamber space (diameter × height), and the maximum load of a heat treatment workpiece (kg) , The maximum heating temperature in the vacuum chamber, the gas pressure used as the gas quenching cooling medium (also known as gas quenching pressure), etc. Generally, a vertical vacuum furnace is used for heat treatment of the ring mold. This is mainly because the ring die needs to be placed flat in the cylindrical vacuum chamber to reduce the deformation caused by vacuum gas quenching. The size of the space in the vacuum chamber and the maximum load of the workpiece mainly depend on the maximum outer diameter and the total weight of the ring die that the feed machinery manufacturer needs to vacuum vacuum quench. The maximum temperature of the ring mold heated in the vacuum chamber will not exceed 1100 ℃, and the general vacuum furnace can meet this requirement. The choice of gas quenching pressure has a great influence on the heat treatment quality and cycle length of the ring die.

There are many manufacturers of vacuum heat treatment furnaces at home and abroad. Figure 1 shows the RVGQ-B vertical vacuum gas quenching heat treatment furnace made by Gehang Vacuum @ SIMUWU vacuum furnace. It is mainly composed of a vacuum chamber with built-in heating elements, a control cabinet with a human-machine interface, a high-pressure gas storage tank for storing gas quenching cooling medium, a gas quenching system equipped with a blower and a heat exchanger, etc., used for maintenance and operation Work bench and vacuum pump. The RVGQ-B vertical vacuum furnace has various sizes of vacuum chambers. The lower end covers of these vacuum chambers can all be opened and automatically moved down to the ground along the column, and then automatically slide out along the guide rails on the ground. Convenience. The maximum heating temperature calibrated in the vacuum chamber can reach about 1400C, and the available gas quenching pressures have three specifications of 0.2, 0.6 and 1MPa. Therefore, the RVGQ-B vertical vacuum furnace is very suitable for the vacuum gas quenching process of the ring mold.