JPH0351535B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing a high-speed cutting tool having high cutting performance. The high-speed steel according to the present invention includes not only the high-speed steel specified by JIS and the steel type generally called powder high-speed steel, but also contains primary carbides and is not subject to secondary hardening during tempering due to the precipitation of alloy carbides. This includes the type of steel produced. [Prior Art] Since high-speed steel has high hardness and excellent toughness, it is used as a material for products that require wear resistance, such as cutting tools and molds. In the fields of cutting and mold forming, there is a tendency for higher work efficiency and precision to be required.
In order to meet these demands, various improvements have been made to high speed steel. For example, according to Japanese Patent Application Laid-Open No. 59-83718, the surface of high-speed steel is irradiated with a laser beam to melt and rapidly solidify the surface to form a solid solution of primary carbides, and then tempering to significantly promote secondary hardening. A method is disclosed in which the hardness and toughness are improved by increasing the hardness and the wear resistance is improved as a result. In order to obtain high power density, it is common for the laser beam in such cases to be focused using a lens, etc., and to be irradiated onto the workpiece in the vicinity of the focused point. At present, the width of the rapidly solidified layer is relatively narrow, about 2 mm.
On the other hand, the cutting tool cutting edge is normally used after being re-ground many times, and if the width of the rapidly solidified layer is as narrow as described above, the number of times that it can be re-grinded is reduced. In other words, although the life of the cutting edge until re-grinding is improved, the reality is that this does not necessarily lead to an improvement in the life of the tool as a whole. In addition, during finishing machining performed after laser beam irradiation, a large machining allowance may be required in relation to machining efficiency, but at this time, if the width of the rapidly solidified layer is narrow, the rapidly solidified layer will be scraped off and disappear. There is a risk of it getting lost. For this reason, when forming the rapidly solidified layer, it is necessary to pay close attention to form the cutting edge or the part where the cutting edge is to be formed (hereinafter simply referred to as the cutting edge) with extremely high positional accuracy. Work efficiency will be significantly reduced. Therefore, in order to eliminate these disadvantages, it is necessary to form a wide rapidly solidified layer. One method is to repeatedly irradiate the surface of high-speed steel 1 with several laser beams 2 to overlap the boundaries, thereby making the rapidly solidified layer 3 wider, as shown in FIG. There is a way. Another method, as shown in FIG. 12, is to increase the spot diameter of the laser beam 2 to widen the area irradiated with the laser beam 2 (melted area 4). [Problems to be Solved by the Invention] However, these methods cause the following problems. First, in the former method, since the overlapped boundary portion (on which a rapidly solidified layer has been formed) is affected by heat, there is a risk that the hardness of the boundary portion may be reduced due to temper hardening. Furthermore, in the case of high-speed steel, the hardness of the rapidly solidified layer and the hardened layer formed by the thermal influence around it is Hv800 or higher, which is very high, so cracks may easily occur. Such cracking has nothing to do with the hardness of the high-speed steel before laser beam irradiation, and will occur even if pre-annealed material is used, so this method cannot be applied to high-speed steel. Next, in the latter method, the power density of the laser beam decreases, so it is necessary to slow down the scanning speed, which results in the problem of slowing down the cooling rate of the molten layer, and the cross-sectional shape of the molten layer As a result of reflecting the power distribution, there is a problem in that not only the surface irregularities become large but also the hardness distribution occurs in the rapidly solidified layer. The present invention has been made in view of these circumstances, and it is possible to form a rapidly solidified layer with a wider width than before without incurring the drawbacks of the prior art described above, and to adjust the heat treatment conditions before beam irradiation. Therefore, the present invention provides a method for manufacturing a high-speed steel cutting tool that completely suppresses the occurrence of cracks due to the widening of the rapidly solidified layer. [Means for Solving the Problem] The present invention consists of the first and second inventions, both of which include a certain amount of material contained in the cutting edge portion or the surface of the cutting edge forming portion of the high-speed steel cutting tool material. By irradiating the line with a high energy density beam while vibrating at high speed and melting the surface layer of the irradiated part, the cutting tool material is relatively moved in a direction intersecting the vibration direction of the beam, thereby cutting the cutting edge. After forming a rapidly solidified layer on the surface of the part or the part where the cutting edge is to be formed, the material is further tempered and finished. In the first invention, the temperature is lower than 130°C below the melting point of the cutting tool material, and in the second invention, although the quenching temperature is not limited, tempering may be performed at 540°C to 700°C after quenching. Each is an important component of the invention. Note that the portion where the cutting edge is to be formed means the area that will become the cutting edge by finishing or re-grinding after beam irradiation. Furthermore, the term "high-speed steel cutting tool" includes not only a tool in which the entire tool is made of high-speed steel, but also a tool in which only the cutting edge part involved in cutting is made of high-speed steel. [Function] FIG. 1 is a diagram showing a method for manufacturing a high-speed steel cutting tool according to the present invention, in which a high-energy density beam (hereinafter simply referred to as a beam) such as a laser beam or an electron beam is applied to the surface of a high-speed steel 1. (sometimes) 12
The surface of the high-speed steel 1 is irradiated with high-speed vibration, that is, repeatedly moving at high speed in the direction of the arrow P, and at the same time either the high-speed steel 1 or the beam 12 is moved in the direction of the arrow Q.
By moving the beam in the direction at low speed, an effect similar to that obtained by irradiating an elongated beam over an arbitrary length corresponding to the width of the beam's high-speed movement can be obtained. As a result, by melting the high-speed steel surface in a range corresponding to the high-speed movement width of the beam 12, a rapidly solidified layer 3 that is wider than before is formed. However, the power density of the irradiation beam does not decrease, and therefore the drawbacks mentioned in the second conventional method do not occur. In addition, since the repeated movement of the beam 12 is performed at high speed, the beam overlap area due to the repeated movement is irradiated at virtually the same time, and is frequently subjected to thermal history such as heating, rapid cooling, and thermal effects. However, the same effect as quenching by rapid melting and solidification can be obtained only once, and the drawbacks mentioned in the first conventional method do not occur. Furthermore, the beam used in the present invention may be a laser beam, an electron beam, or any other beam as long as it is capable of high-speed heating, and the type thereof is not limited, but here, a carbon dioxide laser will be used as an example. The beam irradiation conditions will be explained. In order to improve cutting performance by laser irradiation, it is necessary to form a rapidly solidified layer with a depth of 0.1 mm or more at a cooling rate of 10 ² °C/sec, and the laser irradiation conditions for this are as follows: It is approximately determined by the time during which one point is irradiated (interaction time: T) and the beam intensity at that time (irradiation energy density: W). The relationship between the beam intensity [irradiation energy density W (J/cm ² )] and the interaction time T (seconds) was determined experimentally by irradiating SKH55 (1000℃ quenched material) with a laser beam or electron beam. , T, and W are as follows: 5×10 ^-4 sec<T<10 ^-1 sec...(1) 2×10 ³ J/cm ² <W<2×10 ⁴ J/cm ² ...(2) Ta. Outside the ranges of (1) and (2) above, as shown in Figure 2, evaporation occurs, the depth of the rapidly solidified layer is insufficient, and defects occur in the rapidly solidified layer.
Problems such as insufficient cooling rate occurred, and necessary characteristics could not be obtained. Furthermore, when irradiating a beam that repeatedly moves at high speed as in the present invention, it is further necessary to satisfy the following equations (3) and (4). V/F×16.7<S...(3) F>10(Hz)...(4) Here, each symbol represents the following meaning. S: Spot diameter (mm) F: Frequency of the repeatedly moving beam (Hz) V: Moving speed of the beam or tool in the direction intersecting the high-speed repeating direction (m/min) Equations (3) and (4) above Outside this range, there is a possibility that the molten layer will solidify and melt again during high-speed repeated movement, so there is a risk that cracks will occur regardless of the heat treatment conditions described below, as with the overlap method described above. A heat-affected layer occurs within the rapidly solidified layer, making it impossible to obtain the desired effect. Note that T and W are determined by the following equations. T=S/V×S/D×0.06 (sec) …(5) W=P/D×V×6×10 ³ (J/cm ² ) …(6) (Note: *In case of pulse transmission (multiply the duty for each) where D: amplitude of the repeatedly moving beam (mm) P: beam output (KW). Since the width of the rapidly solidified layer is about 70 to 90% of the high speed repetition width of the beam, it is desirable to set the high speed repetition width of the beam to be 1.1 to 1.4 times the desired width of the rapidly solidified layer. On the other hand, when the beam is an electron beam, the condition range regarding W changes because the beam energy absorption rate differs. That is, the desirable range is 3×10 ² J/cm ² <W<3×10 ³ J/cm ² (2)′, with other conditional ranges being the same. Note that when the laser is a YAG laser, the conditions are the same as those for electron beam irradiation due to absorption rate. In the above condition range, the effect is almost the same as irradiating with a long and narrow beam corresponding to the high-speed movement width (amplitude), and a continuous wide rapidly solidified layer is formed without a heat-affected layer within the molten layer. It was possible. However, in the case of high-speed steel, the quenched hardness is very high, so there is a problem that cracks still occur if this laser treatment is performed after normal quenching. Next, heat treatment conditions for preventing cracking will be explained. First, the representative high-speed steel SKH51,
SKH55, and sintered high-speed steel KHA30 [Fe−1.25
%C-4.0%Cr-5.0%Mo-6.0%W-3.0%V-8.0
%Co (wt%)] was quenched at various temperatures and then used as test materials to investigate the relationship between quenching temperature and hardness. The results were as shown in Table 1 and Figure 3.

[Table] Next, the part where the cutting edge of the hardened high-speed steel tool material was to be formed was irradiated with a carbon dioxide laser under the following irradiation conditions. Test material: SKH51, SKH55, KHA30 Material shape: 30 height x 50 width x 150 length Laser output (P): 3KW Spot diameter (S): Approx. 1.5mm High-speed repetition width (amplitude; D): 10mm Repeated vibration Number (S): 3600Hz Material movement speed (V): 0.3m/min The relationship between the quenching temperature of the obtained tool material and the occurrence of cracks was investigated. The results are shown in Figure 4. Note that the following 5-level evaluation was adopted as a criterion for determining the occurrence of cracks. 1: No cracking occurred. 2: Fine cracking occurred, which could not be visually identified but was visible under 20x magnification. 3: The total length of visible cracks is less than 50 mm or the number of crack origins is 4 or less. 4: The total length of visible cracks is 50 mm or more and 100 mm or less, or the number of crack starting points is 5 or more and less than 10 points. 5: The total length of visible cracks is 100 mm or more or the number of crack starting points is 10 or more. It is clear from Figure 4. As shown, the tendency for cracking to occur decreases as the material quenching temperature before laser irradiation decreases, and it was found that cracking can be prevented by quenching at a temperature below the melting point of 130°C. When the relationship between crack occurrence and quenching hardness was investigated, the results shown in FIG. 5 were obtained. That is,
In terms of quenching hardness, it is better than conventional quenching hardness.
It was found that cracking does not occur if the H _R C5 is lowered. In other words, by performing quenching at a temperature below 130°C below the melting point, which was conventionally performed at 30 to 50°C below the melting point, the hardness of the cutting tool base material can be reduced by H _R C2 to 3 or more compared to the conventional one. , as a result, the plastic deformability increases. Therefore, the tensile stress between the irradiated part and the base material, which occurs when a beam is irradiated to the cutting edge, etc., is alleviated by plastic deformation.
This is thought to reduce cracking. In addition, since the base material of the cutting tool is not the part that directly performs cutting, it does not need to have the same hardness as the cutting edge, which is directly involved in cutting.
It only needs to have enough strength to hold the cutting edge. From this point of view, it is generally considered that a hardness of about H _R C40 is sufficient. Therefore, as is clear from Figure 3, even if the quenching temperature were to drop to 800°C, the quenching hardness of about H _R C40 would be sufficiently achieved, so the quenching temperature should be set at 130°C below the melting point.
Even if the hardness is lowered by more than ℃, the hardness required for the base material (>H _R C40) can be sufficiently obtained. Next, another method for preventing cracking, in which the tempering temperature is limited without limiting the quenching temperature, will be explained. The aforementioned high-speed steel material was quenched at 1200℃ and then tempered at various temperatures to determine the relationship between tempering temperature and hardness. The results are shown in Figure 6. As is clear from FIG. 6, it was found that when the tempering temperature exceeds 500°C, the hardness begins to decrease. Furthermore,
The same laser treatment as above was performed and the relationship between crack occurrence and tempering temperature was investigated, and the results shown in FIG. 7 were obtained. As is clear from Figure 7, the tendency for cracking to occur decreases as the tempering temperature increases, and by tempering at 540°C or higher, cracking is completely suppressed even when the quenching temperature is 130°C or higher below the melting point. It turned out that it was. At that time, when the tempering temperature is within the range of 540 to 560℃, the hardness is almost the same as that of as-quenched, or even higher, but cracking is suppressed due to the improvement in ductility and toughness that accompanies tempering. It seems to be. In addition, if cracking is to be prevented by tempering, the tempering temperature must be 700°C or lower. If tempering is performed above this temperature, the strength required for a cutting tool cannot be imparted to the base material. After forming a rapidly solidified layer under the above conditions, cutting tools are manufactured by further tempering and finishing, but the tempering temperature is the same as in the past, at 500 to 600°C once or multiple times. . It goes without saying that no matter how wide the rapidly solidified layer is, care must be taken to ensure that the rapidly solidified layer is present at the cutting edge during finishing. In addition, the manufacturing process of the cutting tool according to the present invention may include cutting the blade in advance, irradiating it with a beam, then tempering and finishing it, or irradiating the beam onto a material that has not yet been cut, tempering it, and then cutting the blade. Processing may also be performed. In all of the above tests, a laser was irradiated on a square specimen material that had not been cut with a blade to form a rapidly solidified layer, but in addition to this, a rapidly solidified layer was formed on a material that had been cut into the shape of a tool. Tests were also conducted, and it was confirmed that the tendency of cracking in all cases was better than that of square-cut materials, and that under conditions where square-cut materials would not cause cracks, even those that had been cut with a blade did not generate cracks. [Example] A cutting tool (broach) was manufactured by the manufacturing method according to the present invention, and a cutting test was conducted. Example 1 The manufacturing method is shown in FIGS. 8A to 8F. In addition, Figure 8E
is an enlarged sectional view taken along E-E′ of B, and F is an enlarged cross-sectional view of F-
F' is an enlarged sectional view. (b) After rough cutting the high-speed steel annealed material made of SKH55, this high-speed steel cutting tool material 1 is hardened at 1100℃, surface ground and the dimensions are adjusted, and the part where the cutting edge is to be formed is irradiated with beam 2 under the following conditions. 8 Figure A], width approx. 7
Rapidly solidified layers 3 with a depth of about 0.8 mm and a depth of about 0.8 mm were formed at intervals of 1.1 mm. (b) After that, tempering is performed at 560℃ x 1 hour x 3 times,
High speed steel broach material 11 was used. [Figure 8B] (c) Next, groove cutting was performed using the grindstone 5. [FIG. 8C] (d) Next, the cutting edge and flank were finished to obtain a high-speed steel broach 111. [Fig. 8D] In addition, 6 is the base material, 7 is the rake face, and 8 is the flank surface, and the width of the flank face (land width) after finishing machining is
5.5 mm, the blade spacing was 11.0 mm, and the number of blades was 16. The beam irradiation conditions were as follows. Beam type: Carbon dioxide laser beam output: 2.9Kw Spot diameter: 1.5mm High-speed repetition width: 8.5mm High-speed repetition direction: Crossing the cutting edge line Repetition frequency: 3600Hz Tool movement speed: 0.3mm/min Tool movement direction: Cutting edge Center of the rapidly solidified layer parallel to: 2.4±0.8mm from the planned cutting edge line Distance between the rapidly solidified layers: 11.0mm For comparison, we also manufactured a broach using the conventional method with only the beam irradiation conditions changed as shown below. Beam type: Carbon dioxide laser output: 5KW Spot diameter: 2mm Tool movement speed: 2m/min Tool movement direction: Parallel to the cutting edge Center of the rapidly solidified layer: 0.65±0.15mm from the planned cutting edge line Inner distance of the rapidly solidified layer: 11.0 mm No cracking was observed in any of the broaches obtained in this manner. Table 2 shows the time required for the beam irradiation treatment in the above steps.

[Table] As mentioned above, in the conventional method, the allowable range of the beam irradiation position was extremely narrow because the width of the rapid solidification was narrow. In other words, if you try to leave a rapidly solidified layer of 1.5 mm or more from the cutting edge, its center line will be 0.5 mm away from the planned cutting edge line.
Considering that the edge of the rapidly solidified layer is uneven, it must be ground at least 0.2 mm from the edge, so the center line should be separated from the planned cutting edge line by at least 0.2 mm.
It had to be 0.8mm or less. Therefore,
The target position of the irradiated beam was 0.65±0.15mm, which required an accuracy of ±0.15mm. For example, when using a laser beam, the irradiation position of the beam is as follows:
In the conventional method, the irradiation position must be measured every time, as it can vary greatly depending on the slight movement of the reflector and thermal expansion during use. This took about 90 minutes/book. In addition, it was necessary to fix the tool material with a positional accuracy of ±0.15 mm or less, and it took 40 minutes per tool to set it up, check and adjust the fixing position. Furthermore, we confirmed the position of the rapidly solidified layer after irradiation (0.65
It is necessary to use a magnifying glass to check whether the temperature is within ±0.15 mm and the width of the rapidly solidified layer.
It took 90 minutes/book. Including the irradiation time of other high energy density beams, the total
It took 224 minutes. On the other hand, in the method of the present invention, even if the beam irradiation position is slightly shifted, the width of the rapidly solidified layer is wide, so that blade cutting and finishing can be performed while leaving a sufficient amount of the rapidly solidified layer.
The allowable range of irradiation position is wide at ±0.8mm. (In this case, a rapidly solidified layer with a width of at least 5.1 mm remains from the cutting edge.) Therefore, there is no need to check the irradiation position each time, and the setting and fixing position of the tool material can also be checked for 15 minutes/beam irradiation. Since the rapidly solidified layer can be checked visually afterward, 15 minutes per piece is sufficient, and although the beam irradiation time increases slightly, the total time required for processing is 40 minutes, which is significantly shorter than the conventional method. Although the time required for sharpening and finishing was not particularly measured, the workability was improved and the time was shortened due to the wide width of the rapidly solidified layer. In addition, compared to conventional quenching at quenching temperatures (1200-1220°C), the base material hardness is lower, making it possible to process at more than twice the grinding feed rate, greatly improving machining efficiency. . Next, the cutting performance test results will be explained. (a) Cutting edge life The broach according to the present invention manufactured by the above method and the ordinary high-speed steel broach without beam treatment (material: SKH55, quenching temperature: 1220℃,
A cutting test was conducted under the following conditions to compare the cutting performance. Cutting performance was determined by the surface roughness of the material to be cut and the amount of flank wear of the tool. The results are shown in Figure 9. As is clear from Fig. 9, the tool manufactured by the method of the present invention shows almost the same performance as the tool with conventional beam treatment, and the surface roughness of the workpiece is lower than that of the tool without beam treatment. small,
If the cutting length when a certain surface roughness was reached was defined as the life of the cutting edge, there was an effect of improving the life by about 2 to 3 times. Furthermore, Fig. 10 shows the relationship between the maximum amount of wear on the flank surface of the tool and the cutting length. Judging from this result, the cutting length until a certain amount of wear is reached is approximately 2 to 3 mm even without beam treatment. It has doubled. (b) Tool life Since it was confirmed that the life of the cutting edge of the tool manufactured by the method of the present invention is equivalent to that of the tool processed by the conventional beam treatment method, we next investigated the total tool life including re-grinding. I made a comparison. The cutting conditions were the same as before, the cutting edge life was defined as when the surface roughness of the material to be cut reached 10 μm, the rake face was reground by 0.4 to 0.5 mm, and the cutting test was performed again.
By repeating this process, the number of times of re-grinding and the tool life (total cutting length when the tool was re-grinded until it finally became unusable) were determined. The results are shown in Table 3.

[Table] In contrast to the products that were beam-processed using the conventional method, their service life rapidly decreased and abnormal wear occurred after re-grinding four times (possible number of re-grinding is three times). The tool can be re-grinded eight times, which is the same as the tool without beam treatment, and the tool life has been significantly improved. Note that the re-grinding was stopped after 8 times because the land width (width of the flank surface) became narrow. Example 2 Next, in the same manner as in Example 1, brooches of the present invention example and the comparative example were manufactured in the following steps, and the same tests as in Example 1 were conducted. The final tool shape was the same as in Example 1. b) A high-speed steel annealed material made of SKH55 was rough-processed and sharpened, leaving a slight machining allowance in the tool shape, and this was used as a high-speed steel cutting tool material. b) This material is hardened at 1100℃, surface ground,
After adjusting the dimensions, the area where the cutting edge was to be formed was subjected to beam treatment under the following conditions. The land width before beam processing (rough processing state) is
7.5 mm, and 6.5 mm when processed using the conventional method. c) Thereafter, it was tempered at 560°C for 1.5 hours three times, and finished and adjusted to produce a broach product. The beam irradiation conditions in the present invention example and comparative example in the above steps were as follows. Beam irradiation conditions for the example of the present invention Beam type: Carbon dioxide laser output: 3Kw Spot diameter: 1.5mm High-speed repetition width: 8.5mm High-speed repetition direction: Crossing the cutting edge line Repetition frequency: 3600Hz Tool movement speed: 0.3mm/min Tool movement direction: Parallel to the cutting edge Center of the rapidly solidified layer: Center of the land width ±1.0mm Aim Spacing between the rapidly solidified layers: 11.0mm Beam irradiation conditions for comparative example Beam type: Carbon dioxide laser output: 5KW Spot diameter: 2mm Tool movement Speed: 2m/min Tool movement direction: Parallel to the cutting edge Center of the rapidly solidified solid layer: Aim for 1.65±0.15mm from the cutting edge line during rough machining Distance between the rapidly solidified layers: 11.0mm All broaches obtained in this way have no cracking. No occurrence was observed. The time required for beam irradiation treatment was as follows. As in Example 1, the tolerance range of the beam irradiation position when performing beam processing using the conventional method is extremely small at ±0.15 mm, and the beam processing took almost the same amount of time. During rough machining, the blade spacing had to be precisely 11.0 mm, which required additional time for dimensional adjustment and inspection after hardening. This value of ±0.15 mm assumes that a certain amount is searched from the cutting edge during finishing (in this case, 1.0 mm), and the rapidly solidified layer is
We are looking for a range in which it is possible to leave 1.5 mm or more and grind the rapidly solidified layer by 0.2 mm or more.If the rapidly solidified layer is reduced to 1.5 mm or less, the allowable range increases slightly, but the number of re-grinding decreases accordingly. . In contrast, in the method of the present invention, the permissible range of the beam irradiation position is wide, and the spacing between the blades before beam irradiation does not need to be so precise. Furthermore, the time required for beam irradiation itself was shortened to the same extent as in Example 1 for the same reason. Next, a cutting test of the broach manufactured by the above method was conducted in the same manner as in Example 1, and the results were almost the same, that is, the cutting edge life was approximately 2 to 3 times longer than that of the broach that was not subjected to beam treatment. In addition, the number of re-grinding was three times in the case of the conventional beam processing method, whereas the re-grinding was possible eight times in the case of the method of the present invention. Example 3 Next, SKH55 high-speed steel annealed material was quenched at 1200°C and then tempered at 550°C for 1.5 hours 3 times, and after quenched at 1100°C, the same tempering was performed, followed by surface grinding and dimensional adjustment. The resulting material was used as a high-speed steel cutting tool material, and a broach of the same shape was manufactured in the same manner as in Example 1. As a result, no cracking was observed in this broach, and when the same cutting test as in Example 1 was conducted, it showed the same cutting performance (edge life, number of regrinds). [Effects of the Invention] As described above, according to the present invention, it is possible to manufacture a cutting tool having a wide rapidly solidified layer on the cutting edge, and the number of re-grinding of the cutting edge is increased compared to conventional tools, thereby improving the tool life. becomes possible. In addition, since the width of the rapidly solidified layer is wide, there is no risk of the rapidly solidified layer disappearing even if the finish machining allowance is increased to a certain extent, and the rapidly solidified layer can be formed on the cutting edge without paying much attention to the accuracy of the beam irradiation position or the amount of finishing machining. Since it becomes possible to manufacture a cutting tool that has the following characteristics, manufacturing efficiency is significantly improved.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the method of forming a wide rapidly solidified layer by the method of the present invention, Fig. 2 is a diagram showing the relationship between beam intensity and interaction time, and Fig. 3 is a diagram illustrating the quenching of high-speed steel. Figure 4 shows the relationship between temperature and hardness, Figure 4 shows the relationship between quenching temperature and crack occurrence, Figure 5 shows the relationship between quenching hardness and crack occurrence, and Figure 6 shows the relationship between quenching hardness and crack occurrence.
The figure shows the relationship between tempering temperature and hardness, Figure 7 shows the relationship between tempering temperature and crack occurrence, and Figures 8 A to F
9 is a diagram illustrating the broach manufacturing method of the example.
The figure shows the relationship between the surface roughness of the workpiece and the cutting length in the example. Figure 10 shows the relationship between the maximum flank wear amount and the cutting length in the example. Figures 11 and 12 show the conventional method. It is a figure which shows the formation method of the rapidly solidified layer by. 1...High speed steel, 2...Beam, 3...Rapid solidification layer.

Claims (1)

[Claims] 1. After hardening a high-speed steel cutting tool material at a temperature lower than 130°C below its melting point, a high-energy density beam is applied at high speed to a certain line included in the cutting edge portion of the surface or the planned cutting edge formation portion. The cutting tool material is irradiated while being vibrated to melt the surface layer of the irradiated part, and the cutting tool material is relatively moved in a direction crossing the vibration direction of the beam, so that the cutting tool material is applied to the surface of the cutting edge part or the part where the cutting edge is to be formed. A method for manufacturing a high-speed steel cutting tool, which comprises further performing tempering and finishing after forming a rapidly solidified layer. 2 540℃ after hardening high speed steel cutting tool material
Tempering is performed at ~700°C, and then a certain line included in the cutting edge part or the planned cutting edge forming part on the surface is
The cutting tool material is irradiated with a high-energy density beam while vibrating at high speed to melt the surface layer of the irradiated portion while relatively moving the cutting tool material in a direction that intersects with the vibration direction of the beam. A method for manufacturing a high-speed steel cutting tool, which comprises forming a rapidly solidified layer on the surface of a portion to be formed, and then further performing tempering and finishing.