Brief introduction of stainless steel ring die for feed pellet equipment

---

Ring die pelletizer is one of the four main hosts of feed machinery, and it occupies a very important position in the process of feed processing. The ring die is the core component of the granulator and a high-value vulnerable part of the granulator. Its quality directly affects the economic benefits of the user. The feed is extruded through the die hole, and bears the squeezing force of the roller and the friction force of the material for a long time during the use process, causing it to produce bending stress and contact pressure stress; at the same time, iron, steel balls, Impurities such as stones cause the working conditions of the ring die to be very bad, and it is easy to cause the ring die to fail. Most of the existing granulator ring dies are made of high-quality alloy steel and high-chromium stainless steel. These materials have good stiffness and toughness. The heat treatment is integral quenching, the hardness is greater than HRC50, and it has good wear resistance and corrosion resistance, and has a long service life. Longer, the lowest cost of ring die for ton material.

What is the ring die module compression ratio and the calculation method of the compression ratio:

The ring die compression ratio of the pellet machine equipment refers to the ratio of the effective length of the ring die hole to the ring die aperture, which is an indicator reflecting the extrusion strength of the biomass pellet machine. The larger the compression ratio, the stronger the extruded particles, but the output will be relatively reduced. The smaller the compression ratio, the rough surface of the particles and poor molding, but the output will be high. Under the same compression ratio, the larger the roughness value, the greater the particle extrusion resistance, and the more difficult it is to discharge the material. The excessive roughness also affects the quality of the particle surface. The diameter of each small hole of the pellet machine ring die is 6mm, 8mm, and 10mm.

Assuming that the diameter of the ring die hole is 8mm, the die thickness is 66mm, and the release hole is 18mm, then the compression ratio=(66-18)/8=6, and the compression ratio of the die is 1:6

The ring die should be tempered in time after the heat treatment of the SIMUWU brand vacuum air quenching furnace to eliminate the residual internal stress generated during the gas quenching process, improve the plasticity and toughness of the stainless steel material, and make the ring die obtain good comprehensive mechanical properties. In order to ensure that the ring die can maintain high hardness after tempering, and at the same time avoid the temperature zone where the tempering is brittle, it is more appropriate to use 200℃ low temperature tempering for the ring die.

The surface of the ring die processed by the RVGQ-B series vertical bottom-loading vacuum quenching furnace should be very smooth and light yellow. If black marks appear in some places on the surface, you need to check whether the vacuum degree meets the requirements, whether the vacuum chamber and all pipelines are leaking, and whether the purity of the argon used is high enough, and so on. For the martensitic stainless steel material AISI420, using the above heat treatment process, the surface hardness of the ring die after vacuum quenching is about 56~58 HRC, and the surface hardness after tempering is about 54~56 HRC, which meets the ring die heat treatment specifications.

Related information: SIMUWU heat treatment factory, ring die stainless steel module