Pelletizing knife is fixed on the knife plate, close to the granulation belt of the pelletizing die plate, through the high-speed rotation of the mold hole extrusion polymer cutting. Therefore, the pelletizing knife belongs to the wear parts, improve service life and cutting effect, the underwater pelletizing system is extremely important for the overall improvement.
Metal-ceramic composite materials, with high hardness, strong wear resistance, high temperature resistance, corrosion resistance, in the cutting field of a large number of applications, but the shortcomings are prominent, brittle.
Metal-Ceramic Material For The Blade:
The blade part is made of metal material: TiC-NiCr. Briefly analyzed from the material science, TiC is the hard phase and NiCr is the bonded phase of metal ceramics. Therefore, the characteristics of TiC are the characteristics of the blade, high hardness, wear resistance, corrosion resistance and so on.
TiC cermet has a low coefficient of friction, weak polymer adhesion during grain cutting, and low cutting force, which means long cutting time.
TiC content in the range of 30~40%, the hardness of the pilot test, thermal stability, low specific gravity for the best.
NiCr has heat and corrosion resistance, through the control of the sintering cooling rate, welding process to increase part of the fusion of trace metals, etc., so that the bonding phase can be strengthened, and thus strengthen the overall performance of metal-ceramic materials.
Metal-Ceramic Material For The Knife Body:
Knife body part of the selection of 1Cr13 or 40Cr, these two materials can make the knife body has high toughness. Among them, 40Cr in and metal ceramic composite material TiC-NiCr welding fusion is good, welding method is high temperature vacuum diffusion welding. After welding the whole tempering treatment. Tempering hardness according to the actual demand, the principle is lower than the pelletizing die plate surface hardness 7~13HRC.
Metal-Ceramic Pelletizing Knife Failure Analysis:
The aging of the pelletizing knife is mainly caused by wear and tear, the pelletizing knife is fixed on the knife plate, close to the granulation belt of the die plate rotating at high speed.
Cutting knife and die plate gap is large, the force is abnormal; cutting knife and die plate gap is small, friction increases. It is recommended to use the automatic adjustment of the clearance of the pelletizing knife plate: spare knife plate or follow the nature of the knife plate.
Cutting knife in the working process to withstand vibration and impact, the process of knife blade touching the surface of the die plate, resulting in chipping knife. Avoid overloading, and check and replace regularly.
