Metal Cutting Tools Materials--Ceramics

Ceramic tools based on alumina (Al2O3) or silicon nitride (Si3N4) as a matrix and then add a small amount of metal, at a high temperature sintering of a ceramic cutting tool material. Ceramic tools are generally applicable to the fine machining of hard materials at high speed.

Ceramic tools characteristics

1) High hardness and high wear resistance, hardness at room temperature of 91-95HRA than cemented carbide. The ceramic tools can be used for more cutting 60HRC hard material.

2) Have a high heat resistance, and 1200 ° C the hardness is 80HRA, strength, and toughness is reduced less.

3) Have a high chemical stability. Still good resistance to oxidation at high temperatures, the anti-bonding properties, thermal ceramic tools wear less.

4) Has a lower coefficient of friction, the chip is not easy to stick knives, difficult to produce a BUE.

5) Low strength and toughness. Strength only cemented carbide 1/2. Ceramic cutting tool need to select the appropriate geometric parameters and cutting parameters to avoid withstand impact loads, to prevent chipping and breakage.

6) The thermal conductivity is low, only the carbide 1/2 to 1/5, and the thermal expansion coefficient higher than carbide 10% to 30%, which makes the ceramic tools poor thermal shock resistance. The ceramic cutting tool should not have a large temperature fluctuations, generally do not increase the cutting fluid.

Ceramic tools types and application features

1950s ceramic tools is pure alumina ceramic bending strength is lower than 45MPa, using the hot-pressing process in the 1960s of the 20th century, the flexural strength increased to 50 ~60MPa. 1970s alumina adds titanium carbide mixed ceramic using silicon nitride based ceramics in the 1980s; bending strength can reach 70 to 85 MPa. At this point, the application of ceramic tools has made great progress. ceramic tools in recent years has made great achievements in the development and performance improvements, new ceramic cutting tools is a promising ceramic tool material.

1.Alumina carbide ceramics: a certain amount of carbide (typically multi-TiC) is added to the Al2O3, and use made of hot-pressing process, TiC quality fraction of about 30% can be effectively improved when the density strength and toughness of the ceramic, , improved abrasion resistance and thermal shock resistance, so that the blade is not easy to produce hot cracks, unbreakable; alumina carbide ceramics added Ni, Co, W, etc., as a binder metal can be improved alumina and carbonized the bonding strength of the substance. Type of ceramic tools can be used for the processing of high-strength quenched and tempered steel, nickel-based or drill-based alloys and non-metallic materials, due to thermal shock performance improvement can also be used for interrupted cutting conditions milling or planing.

2．Silicon nitride based ceramics

Silicon nitride-based ceramic silica fume by nitriding, sintering aids added after milling placed the cavity hot pressing sintering. The main performance characteristics:

1) High hardness of 1800 ~ 1900HV, good wear resistance.

2) Hat resistance, good oxidation resistance up to 1200 to 1300 ℃.

3) Chemical reaction of silicon nitride with carbon and a metal element is small, the friction coefficient is lower. For cutting steel, copper, aluminum, non-stick scraps, BUE is not easy to improve the quality of the machined surface.

The most important feature of the silicon nitride-based ceramic is more obvious effect of high-speed cutting, turning gray iron, ductile iron, malleable cast iron and other materials. Cutting speed can be increased to 500 ~ 600m/min. Thermal shock resistance than other ceramic tools in cutting and grinding are less prone to chipping.

Silicon nitride ceramic is table for fine cars, semi-finish turning, precision milling or semi-finish milling. Aluminum alloy can be used to fine car to reach the turning instead of grinding. Can also be used for turning 51 ~ 54HRC nickel-base alloy, high manganese steel and other difficult to machine materials.

Chinatungsten Online can provide various sizes and grades of cemented carbide cutting tools,ceramic tools,non-standard products are also customized according to customer requirements. Welcome to consult and purchase sales@chinatungsten.com, sales@xiamentungsten.com .