Performance And Application Of Silicon Nitride Ceramic Cutting Tools

Cutting performance of silicon nitride ceramic cutting tools

(1) High hardness

The room temperature hardness value of silicon nitride ceramic blades has exceeded the best hardness of hard alloy blades, reaching 92.5-94HRA, which greatly 

improves its cutting ability and wear resistance. It can process various types of quenched steel and hardened cast iron with a hardness of up to 65HRC, which can 

save the electricity consumed by annealing processing. Its excellent wear resistance not only extends the cutting life of the tool, but also reduces the number of tool 

changesduring machining, ensuring small taper and high precision when cutting workpieces. Especially when used in high-precision continuous machining CNC machines, 

it can reduce tool errors and unpredictable errors caused by wear, simplifying tool error compensation.

(2) High strength

At present, the bending strength of silicon nitride ceramic blades has reached 750-1000MPa, surpassing that of high-speed steel and comparable to ordinary hard alloys.

(3) Good resistance to high-temperature oxidation

The heat resistance and high-temperature oxidation resistance of silicon nitride ceramic blades are particularly good. Even when cutting at high temperatures from 1200 

to 1450 ℃, they can still maintain a certain hardness and strength for long-term cutting. Therefore, it is allowed to use cutting tools that are much higher than those of 

hard alloy tools to Realize high-speed cutting through cutting speed. Its cutting speed is 3-10 times higher than that of hard alloy cutting tools, thus greatly improving

production efficiency. Experiments have shown that among numerous ceramic materials, Si3N4 ceramics have the best heat resistance.

(4) Good fracture toughness

The fracture toughness value is one of the important indicators for evaluating the damage resistance of ceramic blades, which is related to factors such as material 

composition, structure, and process. The fracture toughness value of Si3N4 series ceramic blades is better than that of other series ceramic blades (up to 6-7MPam1/2), 

which is close to some grades of hard alloy blades. Therefore, it has good impact resistance, especially in milling, planing, sharp cutting, and other intermittent cutting, 

which can demonstrate its superiority.

(5) Strong thermal shock resistance

The thermal shock resistance of ceramic materials refers to an important indicator for evaluating their resistance to damage when subjected to rapid temperature changes. 

The Si3N4 series ceramic blades, due to their high strength and low coefficient of thermal expansion, have a thermal shock resistance performance index of up to 600-800 ℃, 

which is significantly better than other series ceramic blades (300-400 ℃). Therefore, they exhibit unique and superior performance in the rough machining of high-strength 

intermittent parts.