Reasonable selection of blade material for deep ho

2022-07-23
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Reasonable selection of blade material for internal chip removal deep hole drill

internal chip removal deep hole drill is divided into single edge internal chip removal and multi edge staggered tooth internal chip removal deep hole drill. At present, cemented carbide is mainly used as the cutting tool of internal chip removal deep hole drill in China. There are many kinds and brands of cemented carbides. In addition to ordinary cemented carbides (YG, YT, YW), many new types of cemented carbides have been developed, such as fine and ultra-fine grain cemented carbides (YG6X, yd15), surface coated cemented carbides (yb120), cemented carbides with rare earth elements (yw1r), etc. The brands of blade materials commonly used for internal chip removal deep hole drills in China are YG8, YT15, yt798, yw1, etc

requirements for blade materials of deep hole drill with internal chip removal

deep hole drilling with internal chip removal is carried out under closed or semi closed conditions. The cutting heat is not easy to disperse, chip removal is difficult, and the rigidity of the process system is poor. When cuttings are produced continuously or blocked due to poor chip removal during drilling, it will often lead to blade collapse or drill pipe twisting; When the coolant cannot enter the cutting area during drilling, resulting in poor cooling and lubrication, the tool temperature will rise sharply and tool wear will be accelerated; With the increase of drilling depth, the tool overhang increases, and the rigidity of the drilling process system decreases. All these put forward some special requirements for the reasonable selection of the blade material of the internal chip removal deep hole drill tool:

the cutting force is large during the internal chip removal deep hole drilling, the cutting temperature is high, and the abrasive wear, diffusion wear and even oxidation wear of the drilling blade are serious, especially when there are some hard compounds in the workpiece, the wear is more serious, so the hardness of the tool material is required to be higher than that of the processed material, It can maintain high hardness at high temperature and has good wear resistance and durability. The tool is easy to break and twist when drilling with internal chip removal deep hole drill, so the blade material should have strong impact resistance

reasonable selection of blade materials for deep hole drill with internal chip removal

similar to conventional cutting, the selection of bit blade materials is also different for drilling different materials. The general selection principles are as follows:

for the drilling of ordinary carbon steel and alloy structural steel, the chips are easy to control and are relatively easy to cut. Generally, the brand of the blade material is YT15 for the guide block, yt789 for the outer edge of the drill bit, and yt789 or YG8 for the middle and center teeth

deep hole drilling of high strength steel and ultra-high strength steel is difficult to process, with difficult chip breaking, large cutting force, high cutting temperature, fast tool wear and low production efficiency. Generally, cemented carbide with good impact resistance and wear resistance should be selected as the bit blade. Generally, yd15 can be selected for guide block, external edge cutter teeth of drill bit, intermediate cutter teeth and central cutter teeth. High temperature nickel base alloy has large cutting deformation, large work hardening tendency, large cutting force, high cutting temperature, fast tool wear, and difficult to guarantee the quality and accuracy of machined surface. The wear resistance and durability of the cutting tool should be taken into account when selecting the material of the bit blade. Generally, yd15 is selected as the guide block, and yd15, yg10h or 643 are selected as the outer edge, middle and center cutter teeth of the drill bit. Stainless steel grades include 0Cr17Ni4Cu4Nb, 2Cr13, 3Cr13, 4Cr13, 1Cr18Ni9Ti, etc. its large cutting deformation, large cutting force, high cutting temperature, fast tool wear and work hardening make the accuracy and roughness of machined holes worse. The bending strength and wear resistance are mainly considered when selecting the blade brand. Generally, YG8 is selected as the guide block, and YG8, yw1 or 813 can be selected as the outer edge tooth, middle tooth and center tooth of the drill bit. The characteristics of titanium alloy cutting are small deformation coefficient, high cutting temperature, hard and brittle metamorphic layer on the machined surface and serious tool sticking. In addition, titanium alloy will react with YT cemented carbide at high temperature, resulting in adhesive wear and chemical wear. Therefore, YG cemented carbide is mainly used as the blade material for deep hole drilling on titanium alloy. Generally, YG8 or yd15 can be selected for the guide block, external edge cutter teeth of drill bit, intermediate cutter teeth and central cutter teeth

analysis of drilling test effect

drilling test was carried out on n901 high temperature nickel base alloy with a single edge internal chip removal deep hole drill, and the grades of cemented carbide were yd15, yg10h or 643 respectively. The test shows that bright C-shaped chips and spiral curls can be obtained within the range of reasonable cutting parameters. The tool has high durability, stable aperture size, small variation, machining accuracy of it9 ~ it10 and roughness of RA. 3.2 ~ 6.3 m, and the straightness error is within 0.02mm. The multi edge staggered internal chip removal deep hole drill is adopted, and the structure is shown in Figure 1. The cutter teeth are made of YG8, yw1 or 813 that meet the experimental methods and standards. The deep hole drilling test is carried out on 0Cr17Ni4Cu4Nb precipitated stainless steel. The results show that as long as the geometric angle and cutting parameters of the tool are selected reasonably, it can also be used for other low-temperature detection and experimental work, and the ideal drilling effect can be obtained. The friction is relatively large, For example, when the feed rate is 0.08 ~ 0.12mm/r and the cutting speed is 45 ~ 60m/min, bright C-shaped chips and spiral curls can be obtained. The tool has high durability, stable aperture size, small variation, machining accuracy is it9 ~ it10, roughness ra=3.2 ~ 6.3 m, and straightness error is within 0.02mm

when drilling TC4 titanium alloy, YG cemented carbide (YG8 or yd15) is selected. The drill bit structure is shown in Figure 2. The key is to optimize the geometric angle of the tool. Under a reasonable geometric angle, a reasonable range of cutting parameters can be determined. When the feed rate is 0.12 ~ 0.16mm/r and the cutting speed is 30 ~ 40m/min, the drilling effect is the most ideal, the drill bit has good durability and good consistency of hole size, The aluminum alloy cable workpiece thus manufactured has stable processing quality, the dimensional accuracy can reach it9 ~ it11, and the machined surface roughness ra=3.2 ~ 6.3 M. Because the machining process is stable, the radial force of the drill bit changes little, and the guidance is reliable, the most common spiral groove phenomenon in deep hole drilling is eliminated, the deflection of the hole axis is reduced, and the machining quality of the deep hole is guaranteed

the reasonable selection of internal chip removal deep hole drill blade material is one of the main technological measures to ensure the smooth progress of deep hole drilling and improve the tool durability. It is an important factor affecting the machining accuracy and improving productivity

the material of deep hole drill blade mainly depends on the performance of the processed material, and the corresponding cemented carbide should be selected for different processed materials

for deep hole drilling of difficult to machine materials, try to select blade materials with good strength, impact resistance and wear resistance, such as YG8 and yd15

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