JP2003245807A - Cemented carbide made cutting tool exhibiting excellent abrasive resistance in high-speed cutting of hard-to-cut material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cemented carbide made cutting tool that exhibits excellent abrasive resistance in the high-speed cutting of hard-to-cut materials. <P>SOLUTION: The cemented carbide made tool is made of a tungsten carbide base cemented carbide containing 3 to 10 mass% of Co, and 0.1 to 1 mass% of Cr, as a binding phase formation component, and the rest of tungsten carbide as a hard phase forming component and unavoidable impurities. At least the cutting blade surface portion of the tool has a pure copper-infiltrated layer at an average depth range of 100 to 500 μm from the surface. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention exerts an excellent lubricating effect on cutting chips at the time of cutting, and is therefore particularly highly viscous of stainless steel, mild steel, and heat-resistant alloys. Even when used for high-speed cutting of difficult-to-cut materials that are high in cutting power and the chip easily adheres to the cutting blade surface, excellent wear resistance is maintained over a long period without chipping (small chipping) on the cutting blade. The present invention relates to a cemented carbide cutting tool (hereinafter referred to as a cemented carbide cutting tool). 2. Description of the Related Art Generally, a carbide cutting tool is used for turning or planing a work material such as steel or cast iron by being detachably attached to a tip of a cutting tool or a cutter. Away tips, drills and miniature drills used for drilling and cutting the work material, and solid-type end mills used for face milling, grooving, shoulder processing and the like of the work material, etc. There are known throw-away end mill tools and the like, which carry out cutting in the same manner as the solid type end mill by detachably attaching the way chip, and these are manufactured from various tungsten carbide-based cemented carbides (hereinafter, referred to as cemented carbide). It is also well known that it is used for continuous cutting and intermittent cutting of various steels and cast irons. [0003] In recent years, the performance of cutting equipment has been remarkably improved. On the other hand, there has been a strong demand for labor saving, energy saving, and further cost reduction for cutting work. Although there is a tendency to increase the speed, in conventional carbide tools, there is no problem if this is used for continuous cutting or interrupted cutting under ordinary conditions such as low alloy steel or cast iron,
When this is used for high-speed cutting of difficult-to-cut materials such as extremely viscous stainless steel, mild steel, and heat-resistant alloys, the chips of these materials tend to adhere to the cutting blade surface, and this welding phenomenon The higher the speed of the cutting process, the more remarkable it appears. Due to this welding phenomenon, chipping is likely to occur on the cutting blade, and the service life is currently shortened in a relatively short time. [0004] Accordingly, the present inventors have proposed:
In view of the above, the results of research were conducted to develop a carbide cutting tool that does not easily deposit cutting chips on the cutting edge surface, even when used for high-speed cutting of difficult-to-cut materials such as stainless steel and mild steel. , (A) The cemented carbide constituting the cemented carbide cutting tool is
(Hereinafter,% indicates mass%), containing Co: 3 to 10% and Cr: 0.1 to 1% as a binder phase-forming component, and tungsten carbide (WC) as a hard phase-forming component. ) And a cemented carbide having a composition consisting of unavoidable impurities, and at least the cutting edge surface of this
For example, a pure copper thin layer is desirably formed with an average layer thickness of 0.1 to 0.5 mm using a physical vapor deposition method, a plating method, or the like, and is maintained at a temperature of 800 to 1100 ° C. for a predetermined time in a vacuum atmosphere. When the heat treatment is performed under the conditions described above, a pure copper impregnated layer is formed on at least the cutting blade surface of the cemented carbide cutting tool. (B) In the above (a), the thickness from the surface of the pure copper impregnated layer is adjusted to 100 to 500 μm by adjusting the thickness of the pure copper thin layer and the heat treatment conditions.
In the resulting carbide cutting tool, pure copper elutes little by little from the surface of the cutting edge due to the heat generated during high-speed cutting. Existing between the surfaces, the slipperiness of the cuttings with respect to the cutting edge surface is further improved, and since the cutting edge surface always exerts an excellent lubricating effect on the cutting edges, especially stainless steel and Chips of difficult-to-cut materials such as mild steel and heat-resistant alloys do not adhere to the surface of the cutting edge, and as a result, chipping does not occur on the cutting edge, so that excellent cutting performance can be exhibited over a long period of time. Become (A)
The research results shown in (b) and (b) were obtained. The present invention has been made on the basis of the above research results, and contains Co: 3 to 10%, Cr: 0.1 to 1% as a binder phase forming component, and the balance is hard. At least the cutting edge surface of a cemented carbide cutting tool composed of a cemented carbide having a composition consisting of WC as a phase forming component and unavoidable impurities is 100 to 100 mm from the surface.
The present invention is characterized by a carbide cutting tool having a pure copper impregnated layer formed over a predetermined average depth position within a range of 500 μm and exhibiting excellent wear resistance in high-speed cutting of difficult-to-cut materials. Next, the reason why the composition of the cemented carbide constituting the cemented carbide cutting tool of the present invention and the average depth of the pure copper impregnated layer are numerically limited as described above will be described. (A) Co Content of Cemented Carbide The Co component has the effect of improving sinterability and thereby improving the strength of the cemented carbide, but if its content is less than 3%, the desired strength is secured. On the other hand, if the content exceeds 10%, the wear resistance rapidly decreases, so the content is set to 3 to 10%. (B) Cr Content of Cemented Carbide The Cr component forms a solid solution in the Co component, which is a binder phase forming component, and suppresses the growth of WC grains, which are hard phases, but rather refines the WC grains. Has the effect of not only contributing to the improvement in the strength of the cemented carbide, but also contributing to an increase in the pure copper impregnation due to an increase in the grain boundaries accompanying the refinement of the WC grains.
When the content is less than 1%, a desired improvement effect cannot be obtained in the above-mentioned action. On the other hand, when the content exceeds 1%, Cr carbide precipitates as a third phase, which causes chipping. Its content was determined to be 0.1-1%. (C) Average Depth of Pure Copper Impregnated Layer As described above, in the pure copper impregnated layer, the pure copper impregnated hardly forms a solid solution with the binder phase or the WC grains. It coexists in a state of being separated with the binder phase, elutes on the surface of the carbide cutting tool due to heat generated during cutting, and imparts excellent slip properties to the chips by the lubricating action of this eluted pure copper, and on the surface of the carbide cutting tool. It has the effect of suppressing the deposition of chips and preventing the occurrence of chipping at the cutting edge. However, if the average depth is less than 100 μm, the pure copper impregnation amount in the pure copper impregnated layer is insufficient. It is difficult to continue eluting pure copper until the service life of the tool.On the other hand, when the average depth exceeds 500 μm, thermoplastic deformation causing uneven wear occurs at the cutting edge, and the uneven wear causes wear progress. To promote Al, determined the average depth and 100 to 500 [mu] m. Next, the carbide cutting tool of the present invention will be specifically described with reference to examples. As raw material powder,
1.5 μm WC powder, 2.3 μm Cr ₃ C ₂ powder,
And the same 1.4 μm Co powder were prepared, and these raw material powders were blended in the blending composition shown in Table 1 and mixed with a ball mill to obtain
After mixing for 1 hour, the mixture is pressed into a green compact having a predetermined shape at a pressure of 100 MPa, and the green compact is vacuum-pressed in a vacuum of 1.3 Pa at a predetermined temperature within a range of 1380 to 1480 ° C. for 1 hour. By sintering and grinding after sintering, J having substantially the same composition as the above-mentioned composition is obtained.
Comparative carbide cutting tools 1 to 10 each having a shape of a throw-away tip specified in IS • SPGN120308 were manufactured. Next, these comparative carbide cutting tools 1 to 1
0 was charged into a normal arc ion plating apparatus schematically shown in FIG. 1, and pure copper having a purity of 99.99% was mounted as a cathode electrode (evaporation source).
While the inside of the apparatus was evacuated and maintained at a vacuum of 0.5 Pa or less, the inside of the apparatus was heated to 500 ° C. with a heater, and then an Ar gas was introduced into the apparatus to form an Ar atmosphere of 10 Pa. A bias voltage of -800 V is applied to the hard cutting tool to clean the surface of the comparative carbide cutting tool with Ar gas bombardment.
While maintaining the following vacuum, the bias voltage applied to the comparative carbide cutting tool was reduced to -100 V, and the comparative carbide cutting was performed under the condition that an arc discharge was generated between the cathode electrode and the anode electrode. A pure copper thin layer having an average thickness shown in Table 2 was formed on the surface of the tool, which was then charged into a heating furnace, and in a vacuum atmosphere of 0.5 Pa or less, at a temperature of 8:
A heat treatment is performed at a predetermined temperature in a range of 00 to 1100 ° C. for a predetermined time in a range of 1 to 3 hours, and an average depth from the surface shown in Table 2 (a cross section polished to a mirror surface is also shown). Carbide cutting tools 1 to 10 of the present invention were produced by forming a pure copper impregnated layer having a line analysis measurement using an energy dispersive X-ray spectrometer. Next, among the above-described carbide cutting tools 1 to 10 of the present invention and comparative carbide cutting tools 1 to 10 obtained as a result, the carbide cutting tools 1 to 3 of the present invention and the comparative carbide cutting tool 1 Work material: JIS SUS304 round bar, Cutting speed: 200 m / min. Infeed: 1.5 mm Feed: 0.3 mm / rev. Cutting time: 15 minutes Dry dry continuous high-speed cutting test of stainless steel under the following conditions: Carbide cutting tools 4 to 7 of the present invention and comparative carbide cutting tools 4 to 7: Work material: JIS SUJ2 Round bar with four vertical grooves at equal intervals in the vertical direction, Cutting speed: 250 m / min. Infeed: 1.5 mm Feed: 0.3 mm / rev. Cutting time: 15 minutes Dry intermittent high-speed cutting test of mild steel under the following conditions: Further, the carbide cutting tools 8 to 10 of the present invention and the comparative carbide cutting tools 8 to 1
0, work material: round bar of Inconel 718, cutting speed: 100 m / min. Infeed: 1.0 mm Feed: 0.15 mm / rev. A high-speed wet-type cutting test (using a water-soluble cutting oil) was performed on the heat-resistant alloy under the following conditions: cutting time: 10 minutes, and the flank wear width of the cutting edge was measured in each cutting test. The measurement results are shown in Tables 1 and 2. [Table 1] [Table 2] According to the results shown in Tables 1 and 2, the carbide cutting tool 1 of the present invention having a pure copper impregnated layer on the surface of the cutting edge in each case
10 to 10, even when cutting stainless steel and mild steel, and even heat-resistant alloys at high speed with high heat generation, pure copper eluted little by little from the pure copper impregnated layer during cutting imparts lubricity to extremely viscous cutting chips. Since the chips exhibit good slipperiness on the cutting edge surface, chipping due to chip welding to the cutting edge does not occur on the cutting edge,
The comparative carbide cutting tools 1 to 10 exhibit excellent wear resistance but do not have the pure copper impregnated layer on the surface of the cutting edge.
In this case, it is evident that welding of the cutting powder to the surface of the cutting blade is inevitable, and as a result, chipping occurs in any of the cutting blades, resulting in a relatively short service life. As described above, the cemented carbide cutting tool of the present invention is not only capable of continuous cutting and interrupted cutting under ordinary conditions such as various low alloy steels and cast irons, but also has a particularly high viscosity, and the chips are welded to the cutting blade surface. It exhibits excellent wear resistance even in high-speed cutting of stainless steel, mild steel, heat-resistant alloys, etc., which can be easily performed, and can sufficiently respond to labor savings and energy savings in cutting work, as well as lower costs. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view of a normal arc ion plating apparatus.

Claims (1)

[Claim 1] As a binder phase forming component, Co: 3 to 10% by mass, Cr: 0.1 to 1% by mass, the balance being tungsten carbide as a hard phase forming component. At least on the cutting edge surface of a cemented carbide cutting tool composed of a tungsten carbide based cemented carbide having a composition consisting of unavoidable impurities, pure copper over a predetermined average depth position within a range of 100 to 500 μm from the surface A cemented carbide cutting tool that exhibits excellent wear resistance in high-speed cutting of difficult-to-cut materials, characterized by the formation of an impregnated layer.