Corundum coating knife cutting wear a variety of reasons

The color is white corundum state, its simple structure, flexibility is softer than corundum, high reliability and a very wide range of applications. Metal cutting process, resulting in the tool wear is mainly due to the contact between the tool and the workpiece and the friction and blade near the extreme high temperature and pressure conditions. Cutting area of ??any one unit change in contact conditions will affect the tool wear, these conditions include tool material, tool coating and tool geometry specifications, there are other conditions and the physical properties of the workpiece material, corundum cutting tool parameters and the appropriate conditions , cooling and lubrication conditions, the process of cutting machine tool vibration greater or more serious causes the tool to jump fluctuate overload.
Because of different cutting conditions when machining different materials, corundum tool wear mechanism is different: at low cutting speeds, often dominated by abrasive wear; speed cutting, with the cutting speed, cutting temperature increases, bond wear and chemical wear more and more prominent. This paper mainly Ti (C, N) ceramic coated carbide cutting Cr12 mold steel knife tool wear failure analysis studies.
Corundum diffusion wear when cutting steel, cutting temperatures often reach 800 ~ 1000 ℃, or even higher, diffusion wear of carbide cutting tools become one of the main reasons for wear, beginning from 800 ℃, cemented carbide Co, C, W will spread to the chip and other elements to be taken in; the chips to the alloy of Fe diffusion, to form a new, low hardness, high brittleness of the composite carbide. The diffusion of Co, WC, TiC and other carbides reduced due to the Co binder reduce the bond strength with the substrate, which would accelerate the wear of the tool. Meanwhile, the temperature rises to a certain degree of adhesion occurs, therefore, diffusion wear and adhesive wear is often occur simultaneously.
In the tool wear surface morphology observed in the process, we found that more or less the clearance face of the tool, there are some small round particles. To explore these little balls of ingredients, using EDS energy dispersive spectroscopy analysis performed on the part. Found that these pellets mainly composed of a metal Fe and O, presumed to be iron oxides. Corundum ball shape is round, can not be generated in the cutting chips. According to theory of metal crystallization, to form such a round spherical objects, the most likely route is through the liquid - solid transition to achieve, because the liquid substance in order to have a minimum surface energy, with automatic shrink into a ball trend. In high-speed cutting, the temperature is high, although the cutting groove wear areas there is no theoretical temperature at the tip and the rake is high, but the trench oxidation and diffusion regions violent, especially from high-speed chip flow, Tool wear resulting in a trench area in contact with the sharp edges of the chip generates strong friction, wear the trench area and micro contact the local temperature is high, reaching some of the chips on a micro melting temperature, so he formed a lot small balls.
To reduce the corundum small tool wear, cutting parameters can be optimized to ensure product quality and processing efficiency in the case of small cutting parameters selection cutting force for cutting; coating material composition can be optimized to improve the coating material machinability, using advanced multi, multi-layer, gradient coating system, by increasing the intermediate layer to improve the coating and the substrate adhesion and corundum coated cutter when appropriate substrate pretreatment.