JP2000141106A - Tungsten carbide base cemented carbide alloy throw away cutting chip having excellent abrasion resistance and chipping resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the abrasion in a flank of a cutting blade part by orientating a titanium carbide included in the cemented carbide alloy in the vertical direction to a cutting face of the cutting blade part, namely, in a direction in parallel with the flank of the cutting blade. SOLUTION: 5-30 weight % of TiC.whisker in occupying percentage to the whole is included in the cemented carbide alloy forming a cemented carbide chip, and the TiC.whisker is orientated in the vertical direction to a cutting face of a cutting blade part. In the case where the content percentage of the TiC.whisker included in the cemented carbide alloy is less than 5 weight %, it is hard to secure the high strength enough to give the desirable abrasion resistance to the flank of the cutting blade part and the desirable chipping resistance to the cutting face. On the other hand, in the case where the content percentage exceeds 30 weight %, sintering property is lowered, and lowering of the strength due to the lowering of the sintering property is generated, and it is hard to avoid the lowering of chipping resistance. In consideration of this reason, content percentage of the TiC.whisker is desirably set at 10-20 weight %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention shows excellent wear resistance when continuous cutting of steel, cast iron, etc. is performed at high speed conditions, and performs heavy cutting such as high cutting and high feed in intermittent cutting. The present invention relates to a tungsten carbide based cemented carbide throw-away cutting tip (hereinafter referred to as a cemented carbide tip) which exhibits excellent chipping resistance when performed.

[0002]

2. Description of the Related Art Conventionally, a cemented carbide tip generally used for continuous cutting or interrupted cutting of steel or cast iron has a rake face and a flank as shown in a schematic perspective view in FIG. Further, it is well known that it has a shape consisting of a cutting edge ridge portion where the rake face and the flank intersect, and the whole is made of a tungsten carbide-based cemented carbide (hereinafter simply referred to as cemented carbide). is there.

[0003]

On the other hand, in recent years, there has been a strong demand for labor saving and energy saving of cutting work, and accordingly, cutting work has been accelerated, and under heavy cutting conditions such as high cutting and high feed. However, in the above-mentioned conventional carbide inserts, the wear of the cutting edge part progresses extremely rapidly in high-speed cutting, and chipping or chipping (small chipping) occurs in the cutting edge part under heavy cutting conditions. At present, the service life is relatively short in any case.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the viewpoint as described above, the above-mentioned conventional cemented carbide tips were focused on, and as a result of researching to improve the wear resistance and fracture resistance thereof, the cemented carbide constituting the cemented carbide chips accounted for the whole. 5 to 30% by weight of titanium carbide (hereinafter referred to as T
a whisker, and the TiC
・ When the whisker is oriented perpendicular to the rake face of the cutting edge, that is, parallel to the flank of the cutting edge, the resulting carbide tip has a wear of the flank of the cutting edge parallel to this surface. The wear resistance of the cemented carbide tip is remarkably suppressed by the oriented TiC whiskers, and the wear resistance of the cemented carbide tip is generally evaluated by the wear width of the flank of the cutting edge, and the service life is determined by the wear amount. The service life can be prolonged, and the rake face of the cutting edge portion is reinforced by the TiC whisker oriented perpendicular to this face. In general, the occurrence of chipping and chipping of the cutting edge portion is reduced by the rake face. Because of the strong influence of the strength of the steel, the research results showed that it exhibited excellent fracture resistance even in interrupted cutting under heavy cutting conditions.

[0005] The present invention has been made based on the above research results, wherein the cutting edge portion has a rake face and a flank face,
Further, in the cemented carbide tip, which is composed of a cutting edge ridge portion where the rake face and the flank intersect, and is entirely made of a cemented carbide,
Wear resistance in which the cemented carbide contains 5 to 30% by weight of TiC whiskers in a proportion of the whole and the TiC whiskers are oriented in a direction perpendicular to a rake face of a cutting edge portion. And a carbide tip having excellent fracture resistance.

In the cemented carbide chip of the present invention, the content of TiC / whisker in the cemented carbide constituting it is 5 to 30% by weight because the content is 5% by weight.
If it is less than 1, the flank of the cutting edge cannot have the desired excellent abrasion resistance, and the rake face cannot have the high strength enough to give the desired excellent fracture resistance. Is more than 30% by weight, the sinterability is reduced, the strength tends to decrease due to this, and the decrease in fracture resistance is unavoidable. A content ratio of about 20% by weight is good.

Further, the cemented carbide tip of the present invention comprises: (a) a hard phase of tungsten carbide (hereinafter referred to as WC): 54 to 90% by weight; a hard phase of TiC whisker: 5 to 30% by weight; Co-based binder phase and unavoidable impurities containing 15% by weight: residual (however, the total amount of the hard phase is 84 to 95% by weight); (b) WC hard phase: 54 to 90% by weight; Carbides, nitrides, and carbonitrides of elements of groups 4a, 5a, and 6a of the periodic table excluding W, and one or more hard phases of two or more of these solid solutions (hereinafter, referred to as Are collectively referred to as an auxiliary hard phase): 1 to 12% by weight, TiC / whisker hard phase: 5 to 30% by weight, Co-based binder phase containing 4 to 15% by weight and unavoidable impurities : Remaining (however, the total amount of the hard phase is 84-95% by weight), and preferably a cemented carbide having a composition consisting of any of (a) and (b) above. Further, the TiC whisker has a normal aspect ratio of 3 to
It may have an aspect ratio of 60.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the cemented carbide tip of the present invention will be specifically described with reference to examples. As raw material powders, WC powder for forming a hard phase, Co powder for forming a bonding phase, and Cr ₃ C ₂ , each having an average particle diameter in the range of 0.5 to 2 μm
Powder, VC powder, and various auxiliary hard phase forming powders shown in Table 1 were prepared. Further, as TiC whiskers, (1) T of average diameter: 0.3 μm × average aspect ratio: 5
iC whisker (hereinafter referred to as whisker), (2) TiC whisker (average diameter: 0.3 μm × average aspect ratio: 40) (3) average diameter: 0.5 μm × average aspect Ratio: T of 7
iC whisker (hereinafter, referred to as whisker), (4) TiC whisker (average diameter: 0.5 µm x average aspect ratio: 15), (5) average diameter: 1.1 µm x average aspect Ratio: T of 5
iC whisker (hereinafter referred to as whisker); (6) TiC whisker (hereinafter referred to as whisker) having an average diameter of 1.1 µm x average aspect ratio of 10; After forming a 1 μm thick Co thin film on these whiskers by electroless plating, this is inserted into a U-shaped gutter and subjected to slight vibration to give the aforementioned whiskers. With the Co-plated whiskers arranged in the length direction of the gutter, a magnetic field is applied to magnetize them. Then, these raw material powders are respectively blended into the blending compositions shown in Table 1, and the whiskers are blended first. The mixture was wet-mixed with a ball mill for 72 hours, and after the mixing was completed, each of the whiskers was added and mixed gently. After drying, these mixed powders were extruded in a magnetic field, Each of which forms a green compact long oriented in the longitudinal direction of the over, in a vacuum atmosphere of the elongated green compact 10 ^-3 torr, 1,380 to 1,450 ° C.
Vacuum sintering at a predetermined temperature within the range of 1 hour for holding for one hour to form a long sintered body in which each of the whiskers is oriented in the longitudinal direction, and this long sintered body is perpendicular to the longitudinal direction. The cemented carbide tip 1 according to the present invention, in which the whiskers are oriented in the direction perpendicular to the rake face of the cutting edge portion by cutting the cut piece into a cut piece with a predetermined width and finishing the cut piece into the shape of ISO / SNP422 by grinding. To 10 were respectively manufactured. For comparison purposes, comparative carbide tips 1 to 10 were produced under the same conditions except that no whiskers were contained as shown in Table 2.

Next, for the above-mentioned carbide tips 1 to 10 of the present invention and comparative carbide tips 1 to 10, a work material: a round bar of SCM440, a cutting speed: 150 m / min. Infeed: 1.5 mm Feed: 0.3 mm / rev. Cutting time: 20 minutes, Dry continuous high-speed cutting test of alloy steel under the following conditions: Work material: Round bar with four longitudinal grooves at equal intervals in the longitudinal direction of S45C, Cutting speed: 150 m / min. Infeed: 2.5 mm Feed: 0.5 mm / rev. Cutting time: 15 minutes, dry intermittent high feed cutting test of carbon steel was performed under the following conditions, and the maximum flank wear width of the cutting edge was measured in each cutting test.
Table 3 shows the results of these measurements.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

From the results shown in Tables 1 to 3, all of the carbide tips 1 to 10 of the present invention were excellent in continuous high-speed cutting by whiskers oriented perpendicular to the rake face of the cutting edge. In comparison with carbide carbide tips 1-10, they show abrasion resistance and show excellent chipping resistance in intermittent high feed (heavy cutting) cutting without chipping or chipping. Shows inferior wear and fracture resistance, and from these results it is clear that whiskers oriented perpendicular to the rake face of the cutting edge contribute to marked improvement in cutting performance. is there. As described above, the cemented carbide tip of the present invention exhibits excellent wear resistance and chipping resistance not only in continuous cutting and interrupted cutting under normal conditions, but also in cutting at high speed conditions and heavy cutting conditions. Therefore, it is possible to satisfactorily cope with labor saving and energy saving of the cutting process.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a carbide tip.

Claims (1)

[Claims] 1. A throwaway cutting tip, wherein a cutting edge portion comprises a rake face and a flank face, and a cutting edge ridge portion where the rake face and the flank face intersect, and the whole is made of a tungsten carbide-based cemented carbide. The tungsten carbide-based cemented carbide contains 5 to 30% by weight of titanium carbide whiskers in a proportion of the whole, and the titanium carbide whiskers are oriented perpendicular to the rake face of the cutting edge. Throwaway cutting insert made of tungsten carbide-based cemented carbide with excellent wear and fracture resistance. Slowway cutting tip made of.