Cutting Tips

One of the earliest successful applications of sialon and silicon nitride ceramics was as a cutting tip or throw-away insert for cutting or machining nickel based alloys. For these metal forming applications, sialon cutting tools must have a unique combination of thermal and physical properties.

Metal removal generates tremendous heat and even when a coolant is used, temperatures of 1000°C at the cutting edge are commonplace. If a cutting tip has poor thermal conductivity, then the heat generated cannot be easily dissipated. The thermal damage is exacerbated by high thermal expansion coefficient and crater wear develops leading to the rapid destruction of the cutting edge. This thermally induced wear is an important and neglected feature of metal removal.

Most turning operations involve ‘interrupted’ cutting, whether by design or accident. For example, in the turning of a roll of chill-cast iron the existance of pin holes and local asperities makes the cutting action intermittant. Many metal removal operations are by necessity discontinuous and as well as having suitable thermal properties, cutting tools must be tough.

In addition, work pieces are often hard and can be abrasive so the cutting tip should have a high hardness value. Finally, the metallurgical properties of the work piece may be such that at the high temperatures generated a chemical reaction takes place between the tool and the work piece. So chemical stability is also important.

This demanding set of requirements is met by Syalon 050. It is thermally stable up to 1400 °C, thermal shock resistant, hard, tough and strong and chemically resistant to corrosion. In use, Syalon 050 cutting tips reduced by 75% the machining time for turbine discs for a Rolls Royce engine.

For more information on applications of sialon tips for metal cutting and drilling in mining, please contact us. Alternatively download our Metal Forming Applications PDF.