The advantages of vermicular graphite iron cast iron is the heat dissipation and ductile iron strength and elastic modulus set in one. However, it has a graphite structure shaped like a polyp and has a chemical composition that is generally accepted as more difficult to control. As manufacturers, particularly in the truck industry, use vermicular cast iron as the material of choice for diesel engines, they face a variety of processing challenges such as workpiece quality, unpredictable tool life and downtime, all of which can stifle Profitability. However, if the proper tooling is used to machine these materials, it may prove that the machinability of vermicular graphite cast iron is somewhat erratic.
Although polycrystalline cubic boron nitride (PCBN) has proven to be an excellent cutting tool material, it can achieve an almost infinite tool life when cutting gray cast iron. Unfortunately, when machining ductile iron and compacted graphite iron, it is affected by chemical dissolution. In these processes, the tool material interacts with the higher iron content of the cast iron, which can result in rapid tool wear. This challenge has driven the need to develop a tool that is resistant to chemicals.
In order to process these new cast iron materials, it is required that the tool not only improve wear resistance, but also have very good toughness – and these two properties are difficult to take into account at the same time. To meet this challenge, many tool manufacturers are working hard to develop tools that provide the best combination of these two properties.
Most of these inserts are coated grades that combine perfectly with a high-hardness CVD multilayer coating, an anti-deformable rigid base, and a cobalt / cobalt / base-coating interface that enhances the toughness of the cutting edge. These multi-layer CVD coating grades for roughing are designed to improve abrasion resistance and cutting speed so that they can be used to produce highly abrasive castings that may contain sand, surface inclusions, oxides, and others Material that causes rapid tool wear.
This CVD coating grade processing site test results of great significance. Internally intermittently roughing a nodular cast iron bearing part, the CVD coated grade has a 2 times longer tool life than an ISO-P20 roughing insert.