1. High-chromium white cast iron and machining tools
High-chromium white cast iron is the third-generation white cast iron developed from ordinary white cast iron and nickel hard cast iron. At present, high-chromium cast iron is recognized as an excellent wear-resistant material, and it is widely used in mining, cement, electric power, road construction machinery, refractory materials and the like. A simple case of processing high-chromium white cast iron: the outer circumference of the impeller of the slurry pump is turned by the integral PCBN tool. Since the impeller has 5 blades, it is interrupted. The cutting parameters of the Fenike superhard CBN tool are: vc=75m/min, ap=5mm, f=0.1mm/r. During the cutting process, the tool must withstand 5 impacts per revolution of the impeller, and one blade must withstand more than 3,000 impacts in one pass. The cutting results show that: CBN tool does not break and break after cutting a workpiece. One blade is equivalent to 25 ceramic blades, which fully demonstrates its heat and impact resistance, which not only greatly reduces the cost of tool use, but also improves production efficiency. 5 times.
Second, the difference of CBN tools in ordinary white cast iron processing
In the case of white cast iron, turning slag, sand hole difficult to machine cast iron, we can see the most obvious application difference between welded CBN blade and integral CBN blade. Commonly used welded composite CBN tools are mainly used for finishing. The depth of the knife is preferably less than 0.5mm, and it is necessary to avoid intermittent turning. The processing scene of the legend is the inner hole of the integral brake cylinder of the integral CBN blade on the auxiliary tool holder. The cutting parameters are: ap=2.5mm, the amount of cutting f=0.25-0.35mm/r (the rigid vertical car can use a larger cutting edge arc, the feed rate is about 0.45mm), the line speed vc= 120m/min; it can be seen that the cubic boron nitride insert is not as brittle as a ceramic knife, and it is not like the early composite CBN insert, which must use a high cutting line speed.
Abstract White cast iron China has been made into a white cast iron with good abrasion resistance in the spring and autumn period, and it is used as some anti-wear parts. This cast iron has the characteristics of high carbon and low silicon, has high hardness, but is very brittle. The most widely used is high chromium white cast iron with a chromium content of 12% to 20%.
White cast iron China has been made into a white cast iron with good abrasion resistance in the spring and autumn period, and it is used as some anti-wear parts. This cast iron has the characteristics of high carbon and low silicon, has high hardness, but is very brittle. The most widely used is high chromium white cast iron with a chromium content of 12% to 20%, formed in the structure (Cr, Fe ) 7C3 carbide, in which CBN tools for high chromium cast iron and ordinary white cast iron machining have proven to be reliable machining tools.
The picture shows a gray iron casting with a white mouth and a hard spot and sand. The â€œFu Nike Super Hardâ€ monolithic CBN insert is more impact resistant and can be processed intermittently, and it encounters sand and white mouth. Especially suitable for roughing, there is no limit to the depth of the knife (can eat the entire blade); can be turned gray cast iron, cast steel, high chromium white cast iron, chilled cast iron, high temperature alloy cast iron, etc., the life is generally the life of the carbide tool Several times to several tens of times, the processing cost has dropped significantly.