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Halnn PCBN Inserts hard Turning High hardness hardened steel

At present, there are usually 18-30 teeth in each car. As the main basic transmission element in the automotive industry, gears directly affect the noise, stability and service life of the car. And the role of the gear is different, the gear material selected is also different, such as automobile transmission gears, drive axle driving gears, driver differential gears, etc. often use 20CrMoTi, 20CrMo materials; automobile crankshaft gears often use 35, 40, 45 or 40Cr materials. In order to obtain higher hardness, strength, bending fatigue strength and contact fatigue strength (anti-fatigue pitting) of automobile gears during use, heat treatment process is used to improve the hardness, wear resistance and fatigue strength of gears.
 
The hardness of the gear made of 20CrMoTi after heat treatment is 58-64HRC.
There are three tool materials to choose from on the market, namely coated carbide tools, ceramic tools and CBN Inserts. Although the hardness and strength of coated cemented carbide tools are higher than that of coated cemented carbide tools to a certain extent, because the wear-resistant layer on the surface is thin, long-term processing causes the surface wear-resistant layer to be used up. The performance is as non-wearing as uncoated carbide tools. It is not recommended to choose coated carbide tools for mass processing, which will affect the processing efficiency. When processing small or small amounts of gears, without affecting the processing efficiency, you can choose suitable coated carbide tools.
Ceramic tools are brittle and cannot be cut intermittently. They are suitable for finishing and the hardness of the workpiece is between HRC45-55. Therefore, it is more economical to choose ceramic tools for continuous processing and small margins.
Compared with the above two tools, CBN Inserts not only have higher hardness and strength, but also have good wear resistance. Although it is an indisputable fact that traditional CBN Inserts are more brittle, they still have Certain impact resistance. In particular, the non-metal adhesive cubic boron nitride blade developed by Halnn Superhard solves the problem that cubic boron nitride can only be used for finishing processes.
 
Halnn Superhard, as a pioneer in the localization of CBN Inserts in China, its cutting tool solutions can complete a series of machining such as turning and milling of various parts in the hard material processing industry in an all-round and efficient manner. Since its establishment, it has accurately grasped the changing pulse of the times, and has continuously provided high-quality, high-performance tool products that can quickly meet increasingly diverse needs. With long-term accumulated technical strength and cutting-edge technology development capabilities, it is the first domestic application for rough machining. The concept of "Cubic Boron Nitride Monolithic Polycrystalline Inserts" is suitable for contemporary cutting requirements such as "high-speed and precision machining". At present, it is widely used in the field of high-hardness materials, high-hardness workpieces after heat treatment, and other difficult-to-cut materials.
Here is a brief introduction to how Halnn Superhard selects tool grades to process gears.
The machining allowance during the finishing of gears is generally within 0.3mm. For its machining allowance, performance and quality requirements, Valin has developed the BN-H10 grade of non-metal adhesive CBN Inserts for finishing gears. And BN-H20 grades, the above two tool grades are welded CBN Inserts, and the effect of controlling the cutting depth within 0.3mm is better. The main difference is that the working conditions are different, and the selected tool grades are different. The following briefly introduces how to choose the correct tool grade under different working conditions.
1. BN-H05 grade: It is suitable for high-speed continuous fine turning of quenched steel, achieving the effect of Turning replace the grinding, and can replace imported CBN tools. The finish can reach Ra0.2, which can withstand high-speed cutting and has high processing efficiency.
2. BN-H10 grade: suitable for continuous or slightly intermittent fine turning hardened steel. The advantage is that the wear resistance of the single cutting edge is good, and the finish can be achieved within Ra0.4 and accuracy tolerance within 0.02, which can replace imported homogenous product.
3. BN-H21 grade: suitable for strong intermittent finishing machining, that is, intermittent working conditions where the processing surface of the workpiece has a keyway or oil hole, such as: the end face of the gear after quenching (with oil hole), the inner hole of the gear (with keyway) ) Precision turning process to realize the Turning replace the grinding process. The advantage of this tool is that it can withstand medium interrupted cutting, has good impact resistance, and the precision and finish of the finished workpiece are good. 

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