Silicon Nitride Ceramic Cutting Tools used in Machining Superhard Materials

With the development of modern manufacturing technology, traditional carbide cutting tools have been unable to meet the production needs of new and difficult materials. Silicon nitride ceramic cutting tools are favored for their high hardness, strength, good fracture toughness, high-temperature oxidation resistance, and thermal shock resistance, which are widely used in hard cutting, high-speed cutting and so on.

Advantages of silicon nitride ceramic cutting tools

Compared with carbide cutting tools, silicon nitride ceramic cutting tools have obvious advantages, which are shown in the following aspects.

Silicon Nitride Ceramic Cutting Tools

• The HRA value of silicon nitride ceramic cutter is usually 91-93 (HRA is used to represent the hardness index of soft and hard materials), so it has good wear resistance and can be used to process high hard materials that are difficult to be processed by traditional tools or cannot be processed at all, such as various kinds of hardened steel and hardened cast iron with the processing hardness up to HRC65 (60HRA = 20HRC).
• It can be used for rough and finish machining of high hardness materials, as well as for high-impact machinings such as milling, planning and intermittent cutting.
• The cutting tools made of silicon nitride ceramics can be cut at high speed to realize the function of “milling for grinding” for high hard materials, simplify the processing technology and improve the processing efficiency, so as to save time, electricity, number of machine tools and plant area and other effects.
• The silicon nitride ceramic blade has less friction with metal when cutting, which makes it difficult to stick to the blade and the roughness of the workpiece is low.
• The tool’s durability is several times or even dozens of times higher than that of traditional tools, which reduces the number of tool changes during machining, ensures the uniformity of the workpiece, and also ensures small taper and high accuracy.
• The cutting tool consumes the most abundant element silicon in the crust as raw material, which can save a lot of strategic metal materials such as tungsten, cobalt, and titanium.

Applications of silicon nitride ceramic cutting tools

Auto parts processing

A series of parts such as milling cylinder cover, cylinder sleeve, and automobile brake disc are processed with composite silicon nitride ceramic blade, which can improve the efficiency. For example, a milling cutter can increase its speed from 92r/min to 275r/min.

Bearing machining

The rolling bearing adopts the technology of rough, fine, quenching, rough grinding, and fine grinding for a long time. For example, after hardening to 63HRC, the blank of GCr15 precision forging bearing will be deformed and uneven and will get stuck in the rough grinding of the automatic grinding machine directly, and even burn the spindle of grinding machine in serious cases. The finishing process of bearing ring before quenching and the rough grinding process after quenching are combined into the finishing process of ceramic cutter after quenching, which will make the workpiece fully meet the required size and geometric accuracy, realize the substitution of grinding by car and greatly improve the processing efficiency.

Hard cast iron processing

If the composite nitride ceramic tool is used to process the cold cast iron roll, the tool life is increased four times than that of cemented carbide; it can be used to process superhard nickel alloy spray welding roller bushing, which can greatly improve the cutting efficiency and speed, save time and cost and improve economic efficiency.

Other fields

In the fields of machinery, metallurgy, mining, railway locomotive, aerospace, precision instruments, molds, etc., the technology can be reformed by using silicon nitride ceramic cutting tools to greatly improve production efficiency, save energy and reduce cost.

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