The classification of cubic boron nitride cutting tools and use
Date：2016-8-1 Click：4876
Cubic boron nitride cutting tool is mainly used in finishing before, from the raw material purity and grain size in last decade, technical innovation, using composite materials and hot-pressing process and so on, a significant improvement on its brittleness, toughness, using improved reliability, has been applied to routine can be used as a tool in production, play an important role to improve the work efficiency, ensure the quality of products.
Cubic boron nitride cutting tool material performance characteristic:
Cubic boron nitride cutting tool refers to using cubic boron nitride (CBN) cutting part of the tool. Cubic boron nitride (CBN) is one of boron nitride BN isomers with element, structure similar to diamond, is to use ultra high temperature and ultra high pressure technology of artificial superhard materials. Its hardness is second only to diamond (microhardness of up to 8000 ~ 8000 hv), thermal stability and high (1250 ~ 1350 ℃), large chemical inertness of iron group elements, strong compressive，resistance,With diamond grinding wheel grinding edge, so it is suitable for processing more than 35 HRC hard material, such as a variety of hardened steel, carbon tool steel, alloy tool steel, high speed steel, bearing steel and die steel, etc.), chilled cast iron, cobalt and nickel based high temperature alloy, hard alloy, surface spraying (welding) materials such as hard and wear-resistant materials, can also be used for titanium alloys, pure nickel, tungsten, and other materials processing. It is the car, one of the best cutter mill instead of grinding. With cubic boron nitride cutting tool processing and surface roughness of hardened steel for Ra1.60.4 microns, the precision can reach IT7IT6.
Cubic boron nitride cutting tool also has limitations on use, as its brittleness is bigger, strength and toughness is bad, not suitable for discontinuous surface processing under shock load. In addition, the processing of soft iron material with it, because of easy to produce long chip, scratch tool rake face and the devolop tumor formation, damage to the cutter can lead to the fluctuation of cutting force.
In order to improve the shock resistance performance of cubic boron nitride cutting tools, now we have developed in class graphite of hexagonal boron nitride (g - BN or h - BN) as raw material, using the explosion method synthesis of a new type of WBN materials (WBN belong to lead-zinc mine structure of BN). It has the very high toughness and sintering activity, extremely easy to CBN, strength and hardness and easy and CBN burn form close to the standard of CBN crystals.
WBN and CBN two-phase sintered body is made of WBN toughness to offset the brittleness of CBN, the impact strength is relatively simple CBN sinter increased by 60%, the fracture toughness increased by 2.53 times, one times around the flexural strength, compressive strength and cemented carbide, thermal stability of 1100 ~ 1200 ℃. Can be used to machining gap on the surface of the workpiece, such as gear tooth surface, welding surface or slotted artifacts.
At present, the two-phase sintered body of WBN and CBN cutting tool has been in the United States, Japan and Russia and other countries are widely used in the automotive industry, such as used for processing and connecting rod, a cylinder, cylinder liner, brake wheel, crankshaft, flywheel shell, all kinds of pump parts, such as boring and milling process.
