Research on CBN Tool for Intermittent Machining of Hardened Steel Issued by: Zhengzhou Hualing Superhard Materials Co., Ltd. As a kind of difficult-to-cut machining material, hardened steel has always been the research topic of CBN tool industry. Especially the intermittent machining of hardened steel has always been a big problem. CBN tools will impact more than 100 times per minute in intermittent machining of hardened steel. To complete the machining, the impact resistance of the CBN tool is a big challenge. Intermittent machining characteristics of hardened steel According to the length of one continuous cutting duration and the ratio of cutting time to total time, one workpiece can be divided into continuous cutting, high frequency interrupted cutting and low frequency interrupted cutting; intermittent surface cutting, machining workpiece and turning tool The tool is constantly subjected to impact and vibration, and there are often phenomena such as missing parts, moving parts, broken knives, and boring cars during processing. The work efficiency is low and the quality is difficult to guarantee. Taking automobile gear processing as an example, the hardening of hardened gears has become a trend. Although hard turning of hardened steel has become very popular, in fact, many problems are still encountered in the process of hardened gears of automobiles. Oil hole, which has the problem of intermittent cutting. Many CBN tools encounter oil holes and break the knife during high-speed operation. The position tolerance of the gear is difficult to guarantee, etc. Research on CBN Cutter for Intermittent Machining of Hardened Steel 1, hardened steel hardness conversion misunderstanding The hardness of the hardened steel is supplemented by the additional formula HRC=100-37353/(HV+200) to obtain very accurate results, which is very convenient in practical applications. This is generally the "black metal hardness and strength conversion table" for the hardness comparison table that is often used by everyone. It is not suitable for hardened steel and high speed tool steel. For example, the HV700 control HRC hardness in the metal hardness and strength table is 59.5; and according to the "hardened high speed steel Rockwell hardness and Vickers hardness conversion standard" HV700 conversion, the HRC hardness value is 41.6; the difference is nearly 20 HRC hardness. ! 2, the selection of tools for quenching steel during intermittent cutting When intermittently machining hardened steel, it is selected from two types of tool materials: coated hard alloy and CBN tool according to the hardness and processing parameters of the workpiece. (Ceramic tools have poor impact resistance, generally only for continuous finishing.) (1), coated carbide tool: suitable for HRC45 hardness workpiece processing, relatively low speed turning, if it is occasionally processed hardened steel, you can consider the carbide grade, such as YT726 and other brands. (2), CBN tool: It is most suitable for workpieces with hardness above HRC45 hardness after quenching. There are two kinds of CBN tools. The common welding compound CBN tools on the market can only control the depth of the knife to be less than 0.3mm. In the case of intermittent cutting, the machine often collapses. Although foreign CBN tools are capable of intermittently cutting some new grades of CBN tools, most of them are used for weak interrupted cutting and super-finishing optical knives. At present, there are many manufacturers of CBN welding tools in China. Most of them are made of various CBN tools by cutting and welding with foreign CBN composite sheets. It is very clear that the complex grade characteristics of foreign CBN tools are not clear. This is also the domestic CBN. The embarrassing situation of the welding tool market. In view of the difficult problem of intermittent machining of hardened steel and the unresolved problem of CBN tool industry, HLCBN tool developed by Hualing Superhard is an important advancement in the tool industry. HLCBN series tools are called strong intermittent in the industry. The world model for turning hardened steel. As shown in the processing case: Figure 1: Strong interrupted cutting of hardened steel: Large gear (tooth ring) after carburizing and quenching is severely deformed, the outer ring deformation of the gear ring is up to 2mm, and the hardness after quenching is HRC60-65 cutting line speed: 50-- 70m/min, the depth of the knife is 1.5--2mm. The amount of the knife is 0.15-0.2mm/per revolution. The original imported ceramic tool can only be cut by multiple passes to cut the deformation, and the chipping is serious, and the tool cost is very high. HLCBN tool test results: Compared with the original imported silicon nitride ceramic tool, the impact resistance is 6 times longer than the original tool when the depth of the knife is increased by three times! The cutting efficiency has been increased by a factor of three (the original is three passes, now it is once completed). The surface roughness of the workpiece also meets the user's requirements. The most valuable thing is that the final failure form of the tool is not a worrying blade, but a normal flank wear. The intermittent turning and quenching gear outer circle experiment broke the myth that the industry CBN tool can not be used for strong intermittent turning hardened steel! In the knives academic world caused a lot of sensation! Figure 2 shows the inner hole of the end face of the automobile gear. For continuous cutting, the welded CBN tool can be used for finishing the car. CBN tool angle and life relationship Intermittent machining hardness HRC65 hardened steel workpiece, CBN tool angle is 0.2 * 20 degrees negative chamfer, the tool bar design has a pre-loading angle (-6 degrees) and a back angle (6 degrees). In the intermittent machining process of hardened steel, the main cause of tool life is mechanical impact; when the negative chamfering angle is large, the combination of cutting temperature and mechanical impact is the main factor affecting tool life. Zhengzhou Hualing Superhard Materials Co., Ltd. Copyright Fluorinated Fluorobenzoic Acid 2-Bromo-6-Fluorobenzoic Acid,6-Fluorobenzoic Acid,Bromo-6-Fluorobenzoic Acid Fluorinated Fluorobenzoic Acid Co., Ltd. , http://www.nsfluorinated.com