JP2000052130A - Pin milling-cutting ring body cutter for crankshaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ring body cutter having a component or a cutting tip displaying an excellent resistance to damage in a high speed pin milling-cutting operation. SOLUTION: A cutting tip contains 9 to 13% Co, 0.5 to 1.5% Cr as binder phase forming components, 0.5 to 3% TaC and/or (Ta, Nb)C as hard phase forming components, and comprises, from the substrate surface side in sequence, TiN layer having average layer 0.1 to 1 μm thickness as the first layer, TiCN layer having average layer 2 to 10 μm thickness as the second layer, TiCO layer, TiNO layer, and TiCN layer having average layer 0.1 to 1 μm thickness as the third layer, α type Al2O3 layer and/or κ type Al2O3 having average layer 0.5 to 2.5 μm thickness as the fourth layer, and TiN layer having average layer 0.1 to 1 μm thickness as the fifth layer. Plural cutting tips formed by depositing the hard coating layer composed of the first layer to the fifth layer with a total average layer 3 to 13 μm thickness by chemical vapour deposition and/or physical vapour deposition, are locked to a cutter so that they can be freely removed and replaced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cutting tip, which is a component of a crankshaft and a journal (particularly a journal), which is excellent in chipping resistance, especially when the crankpin portion and the shaft portion (journal portion) of the crankshaft are milled. The present invention relates to a ring cutter that exhibits excellent cutting performance throughout.

[0002]

2. Description of the Related Art Conventionally, as shown in a schematic perspective view of FIG. 1, a plurality of cutting tips 1b are detachable at predetermined positions along an inner peripheral surface or an outer peripheral surface of a ring-shaped main body 1a made of alloy steel. Milling of the crank pin portion 2a and the shaft portion (journal portion) 2b of the crankshaft 2 using the ring cutter 1 fixed to the shaft (hereinafter, these are collectively referred to as pin milling cutting). Has been done. Further, as a cutting tip which is a constituent member of the ring cutter, a surface of a substrate (hereinafter, referred to as a super-hard substrate) made of a cemented carbide mainly containing tungsten carbide (hereinafter, referred to as WC) is provided. Also has a granular crystal structure, a titanium carbide (hereinafter referred to as TiC) layer, a titanium nitride (hereinafter also referred to as TiN) layer, a titanium carbonitride (hereinafter referred to as TiCN) layer, a titanium carbonate (hereinafter referred to as T
iCO) layer, titanium oxynitride (hereinafter referred to as TiNO) layer, and titanium carbonitride (hereinafter referred to as TiCNO) layer, and further, for example, JP-A-7-328808 and JP-A-6-8010. As described in above, titanium carbonitride having a vertically-growing crystal structure formed by performing vapor deposition at a medium temperature range of 700 to 950 ° C. using a mixed gas containing an organic carbonitride as a reaction gas (hereinafter, referred to as one or two of the layers (denoted by 1-TiCN)
Α-type aluminum oxide (hereinafter referred to as α-Al ₂ O ₃₎ having a Ti compound layer composed of at least
) And / or a κ-type aluminum oxide (hereinafter referred to as κ-Al ₂ O ₃ ) layer by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of 3 to 20 μm. Cutting tips are widely known.

[0003]

On the other hand, during the pin milling of the crankshaft, the cutting tip of the ring cutter used in the crankshaft is subjected to intense mechanical shock due to the intermittent cutting mode and intense heat accompanying a large slip ratio. Although impact is applied, there is a strong demand for performing this pin milling cutting at a high speed in terms of labor saving and energy saving. Thus, when the pin milling cutting is performed at a high speed, mechanical shock and thermal shock applied to the cutting tip are increased. Is more intense, and as a result, the cutting edge of the cutting tip is more likely to be chipped or chipped (small chipping), and as a result, the service life of the cutting tip can be shortened in a relatively short time.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoint, attention was paid to the cutting tip constituting the ring body cutter, and a study was conducted to improve the chipping resistance of the cutting body. As a result, the weight of the cemented carbide substrate constituting the cutting tip of the ring body cutter was reduced to% by weight. (Hereinafter,% indicates weight%)
Co: 9 to 13% as a binder phase-forming component, 0.5 to 1.5% of Cr as a binder phase-forming component, tantalum carbide (hereinafter referred to as TaC) and / or as a hard phase-forming component.
Or a complex carbide of Ta and Nb [hereinafter, (Ta, Nb)
C]: 0.5 to 3%, the remainder being specified as a cemented carbide having the same composition as WC as a hard phase forming component and unavoidable impurities, and chemical vapor deposition on the surface of the cemented carbide substrate. And / or the configuration of the hard coating layer to be physically deposited is from 0.1 to 1 as the first layer from the substrate surface side.
TiN layer having an average layer thickness of μm;
1-TiCN layer having an average layer thickness of 0 μm, TiCO layer having an average layer thickness of 0.1 to 1 μm as a third layer, Ti
One or more of a NO layer and a TiCNO layer, an α-Al ₂ O ₃ layer and / or a κ-Al ₂ O ₃ layer having an average layer thickness of 0.5 to 2.5 μm as a fourth layer ,
TiN having an average layer thickness of 0.1 to 1 μm as a fifth layer
When the layers are specified as the first to fifth layers and the total average layer thickness is limited to 3 to 13 μm, the resulting super-hard substrate having the above composition and the hard coating layers of the first to fifth layers are obtained. When the cutting tip composed of is attached to the ring body cutter and performs pin milling of the crankshaft, it shows not only cutting under normal conditions but also excellent fracture resistance even at high speed cutting, The research results show that they exhibit excellent cutting performance over a long period of time.

The present invention has been made on the basis of the above research results, and has Co: 9 to 9 as a binder phase forming component.
13%, also as a binder phase forming component: Cr: 0.5 to
It contains 1.5%, TaC and / or (Ta, Nb) C: 0.5 to 3% as a hard phase forming component, and the rest has the same composition as WC as a hard phase forming component and inevitable impurities. On the surface of a cemented carbide substrate made of cemented carbide, from the substrate surface side, a TiN layer having an average layer thickness of 0.1 to 1 μm as a first layer, and a TiN layer having an average layer thickness of 2 to 10 μm as a second layer. -TiCN layer, 0.1 to 3rd layer
Α-Al having an average layer thickness of 0.5 to 2.5 μm as a fourth layer, one or more of a TiCO layer, a TiNO layer, and a TiCNO layer having an average layer thickness of 1 μm
_{A 2} O ₃ layer and / or a κ-Al ₂ O ₃ layer, a TiN layer having an average layer thickness of 0.1 to 1 μm as a fifth layer, and a hard coating layer composed of the first to fifth layers. 3 to 13 μm
A plurality of cutting tips formed by chemical vapor deposition and / or physical vapor deposition with an overall average layer thickness of at least one at a predetermined position along the inner or outer peripheral surface of the alloy steel ring-shaped main body; The ring cutter is characterized by exhibiting excellent fracture resistance against large mechanical shock and thermal shock generated during high-speed pin milling.

[0006] Next, in the cutting tip of the ring cutter of the present invention, the composition of the super-hard substrate constituting the cutting tip, the average layer thickness of the constituent layers of the hard coating layer, and the overall average layer thickness are limited as described above. Explain why. A Composition of Carbide Substrate (1) Co The Co component improves the sinterability and forms a binder phase to increase the strength, and also causes a chipping or chipping of the cutting edge due to mechanical impact. Is an indispensable component for ensuring toughness that suppresses cracking. However, if the content is less than 9%, desired strength and toughness cannot be obtained. On the other hand, if the content exceeds 13%, especially at the time of high-speed cutting, Since plastic deformation is likely to occur on the cutting edge, which causes wear to progress, the content is set to 9 to 13%.

(2) Cr The Cr component forms a binder phase together with a solid solution in Co, improves the heat resistance of the binder phase, and also causes the chip to be chipped even by a large thermal shock during high-speed cutting. Has the effect of suppressing the formation of a hard coating layer and further improving the adhesion to the hard coating layer. However, if the content is less than 0.5%, the desired effect cannot be obtained in the above-mentioned action. If it exceeds 5%, the cutting edge is liable to be broken due to a large mechanical impact particularly at the time of high-speed cutting, and this causes wear to progress. Therefore, the content is set to 0.5 to 1.5%. Was.

(3) TaC and (Ta, Nb) C These components have an effect of remarkably improving the chipping resistance of the cutting edge against thermal shock. However, if the content is less than 0.5%, desired contents are obtained. When the effect of improving the fracture resistance cannot be obtained, and when the content exceeds 3%, the fracture resistance to a large mechanical impact at the time of high-speed cutting is reduced, so that the content is 0.5 to 0.5%. It was set at 3%.

B. Average Layer Thickness and Overall Average Layer Thickness of Hard Coating Layer (a) TiN Layer The TiN layer is used to form hard coating layers such as W, Co, and Cr components, which are constituents of a superhard substrate. Blocking the diffusion movement of
In addition to having the effect of suppressing the reduction in wear resistance of the hard coating layer, the hard coating layer adheres to the surface of the super hard substrate with high adhesion strength, and has the effect of improving the adhesion of the hard coating layer to the surface of the super hard substrate. If the layer thickness is less than 0.1 μm, the above effect is not sufficiently exhibited, while the effect is sufficient with a layer thickness of up to 1 μm. Therefore, the layer thickness is set to 0.1 to 1 μm.

(B) l-TiCN layer Since the l-TiCN layer has a structure in which crystals grow in a direction perpendicular to the cutting edge surface, that is, a vertically-grown crystal structure, the l-TiCN layer is cut during pin milling of a crankshaft. In addition to exhibiting a strong resistance to thermal shock that progresses from the blade surface in the depth direction, it has the effect of further improving the fracture resistance of the hard coating layer, coupled with its own excellent toughness, but the layer thickness is less than 2 μm If the layer thickness exceeds 10 μm, on the other hand, if the layer thickness exceeds 10 μm, the cutting edge is likely to undergo thermoplastic deformation, which causes uneven wear. It was decided.

(C) TiCO layer, TiNO layer, and T
iCNO layer Generally, for example, an l-TiCN layer and an α-Al_Two O_Three Layer density
Adhesion is relatively low, and when both are directly laminated,
It causes the peeling of the hard coating layer.
Each of the layer and the TiCNO layer has l-TiCN
Layer, α-Al_Two O _Three Layer and κ-Al_Two O_Three Any of the layers
Tightly adhered to each other, and thus the adhesion between the constituent layers of the hard coating layer
Has the effect of improving the performance, but the layer thickness is 0.1 μm
If the amount is less than the desired value, the desired effect of improving the adhesion cannot be obtained.
If the thickness exceeds 1 μm, chipping tends to occur on the cutting edge.
Therefore, the layer thickness was determined to be 0.1 to 1 μm.

(D) α-Al ₂ O ₃ layer and κ-Al ₂
O ₃ layer The α-Al ₂ O ₃ layer and the κ-Al ₂ O ₃ layer are both excellent in oxidation resistance and thermal stability, and are particularly a blocking layer against a large amount of generated heat during high-speed pin milling cutting. Acts to improve the chipping resistance against thermal shock, and has the effect of improving the wear resistance due to its own high hardness. However, if the layer thickness is less than 0.5 μm, the above effect does not have the desired effect. On the other hand, if the layer thickness exceeds 2.5 μm, chipping is likely to occur on the cutting edge. Therefore, the layer thickness is set to 0.5 to 2.5 μm.

(E) TiN layer The TiN layer improves the initial conformability with the work material and enables smooth start of cutting. In addition, since the TiN layer itself has a golden color tone, the cutting tip Has a function of facilitating the discrimination between before and after use. However, if the layer thickness is less than 0.1 μm, the desired effect of the above-mentioned effect cannot be obtained. On the other hand, a layer thickness up to 1 μm is sufficient. For this reason, the layer thickness was determined to be 0.1 to 1 μm.

(F) Overall Average Thickness of Hard Coating Layer If the thickness of the hard coating layer is 3 μm, the desired excellent wear resistance cannot be secured, while if the thickness exceeds 13 μm,
Since chipping easily occurs on the cutting blade, the overall average layer thickness is set to 3 to 13 μm.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the ring body cutter of the present invention will be specifically described with reference to embodiments. First, as raw material powder, WC powder having an average particle diameter of 5 μm, 1 μm
Of TaC powder and 1 μm of (Ta, Nb) C (TaC /
NbC = 90/10) powder, 1 μm Cr ₃ C ₂ powder, and 1.2 μm Co powder were prepared, and these raw materials were mixed in the composition shown in Table 1 and wet-mixed for 72 hours using a ball mill. And after drying, 1 ton / cm ²
It was pressed into a green compact at a pressure of, the green compact, ^10-2
The ring cutter of the present invention, which is sintered in a torr vacuum at a predetermined temperature in the range of 1320 to 1450 ° C. for 1 hour, and is made of a cemented carbide, and has a vertical blade type special shape. Carbide substrates (hereinafter, referred to as the present invention superhard substrate) A to H, and superhard substrates for a comparative ring body cutter (hereinafter, referred to as comparative superhard substrate) a to h were produced.
In the comparative superhard substrates a to h, at least one of the components constituting the components (components marked with * in the table) is out of the scope of the present invention.

Next, the surface of each of these various super-hard substrates is
With the honing performed, a normal chemical vapor deposition apparatus was used, and Table 2 (the l-TiCN layer in the table has a vertically-grown crystal structure, and the l-TiCN layer is disclosed in
Under the conditions shown in No. 8010, a TiCN layer having a vertically elongated crystal structure), a hard coating layer having the composition and target thickness shown in Tables 3 and 4 was formed. The cutting tips A to H for the ring body cutter of the present invention (hereinafter, referred to as the cutting tips of the present invention) and the cutting tips a to n for the comparative ring body cutter (hereinafter, referred to as the comparative cutting tips) were produced. In addition, among the comparative cutting tips a to n, the comparative cutting tips a to h are:
The configuration of the hard coating layer is the same as that of each of the cutting tips A to H of the present invention, except that the cemented carbide substrate is constituted by the comparative cemented carbide substrates a to h. The average thickness of any one of the hard coating layers formed on the surfaces of the inventive super-hard substrates A to H is out of the range of the present invention.

Next, the cutting inserts A to H of the present invention and the comparative cutting inserts a to n are of the internal (inner peripheral blade) type shown in FIG. 1, respectively. Diameter: 320mm x thickness:
33mm in size and number of cutting inserts: 4
The ring-shaped cutters 1 to 8 of the present invention and the comparative ring-shaped cutters 1 to 14 were respectively manufactured by attaching to zero ring-shaped bodies made of SCM415 (chromium molybdenum steel).

Using the resulting ring body cutters 1 to 8 and comparative ring body cutters 1 to 14 of the present invention, a work material: carbon steel having a length of 500 mm (S50C)
Section of a 4-cylinder crankshaft made of steel, Cutting speed: 300 m / min. , Feed: 0.06-0.15mm / tooth, Pin part allowance: 2-3mm, Dry high-speed pin milling cutting test of the crankshaft was performed under the following conditions, and the flank wear width of the cutting edge of the cutting tip was reduced. The number of processed pin portions up to 0.2 mm was measured. Table 5 shows the results of these measurements.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

From the results shown in Tables 1 to 5, the ring body cutters 1 to 8 of the present invention can be used to cut the cutting tip, which is a component of the ring body cutters, even if the pin milling of the crankshaft is performed at a high speed. While excellent wear resistance is exhibited without occurrence of chipping on the cutting edge, any one of the constituents of the cemented carbide substrate of the cutting tip constituting this, as seen in the comparative ring cutters 1 to 14 Even if the content of the hard coating layer deviates from the range of the present invention, or if the average layer thickness of any of the constituent layers of the hard coating layer deviates from the range of the present invention, chipping of the cutting edge of the cutting tip will occur in high-speed cutting. Is inevitable,
It is clear that this leads to a relatively short service life. As described above, the ring body cutter according to the present invention is not limited to the pin tip milling under the normal conditions of the crankshaft, but also the cutting tip which constitutes the same even when these cuttings are performed at a high speed. It shows excellent fracture resistance and exhibits excellent wear resistance over a long period of time, contributing to labor saving and energy saving in cutting.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a pin milling cutting mode of a crankshaft by a ring cutter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ring body cutter 1a Ring-shaped main body 1b Cutting tip 2 Crankshaft 2a Pin part 2b Shaft part

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kazuhiro Kono 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Pref. F-term in the Tsukuba Works, Mitsubishi Materials Corporation BD05 EA01 4K030 AA03 AA09 AA10 AA14 AA17 AA18 BA18 BA35 BA38 BA41 BA43 BB01 BB03 BB12 CA03 JA01 LA01 LA22

Claims (1)

[Claims] 1. Co: 9 to 13 as a binder phase forming component
%, Also 0.5 to 1.5% of Cr as a binder phase forming component, and tantalum carbide and / or Ta as a hard phase forming component.
Composed of a cemented carbide containing 0.5 to 3% of a complex carbide of Nb and Nb, the remainder being also composed of tungsten carbide as a hard phase forming component and a composition (above, by weight) consisting of unavoidable impurities. A titanium nitride layer having a granular crystal structure having an average layer thickness of 0.1 to 1 μm as a first layer, and a vertically-growing crystal structure having an average layer thickness of 2 to 10 μm as a second layer. One or two of a titanium carbonate layer, a titanium oxynitride layer, and a titanium oxycarbonitride layer having a granular crystal structure having an average layer thickness of 0.1 to 1 μm as a third layer. As described above, an α-type and / or κ-type aluminum oxide layer having a granular crystal structure having an average layer thickness of 0.5 to 2.5 μm as a fourth layer, and a granular layer having an average layer thickness of 0.1 to 1 μm as a fifth layer. A titanium nitride layer with a crystalline structure, The cutting tip obtained by chemical vapor deposition and / or physical vapor deposition of the hard coating layer composed of the first to fifth layers with a total average layer thickness of 3 to 13 μm is formed on the inner peripheral surface of the alloy steel ring-shaped body or A ring cutter for pin milling of a crankshaft for a crankshaft, in which a plurality of the cutting tips, which are constituent members, are removably fixed at predetermined positions along an outer peripheral surface and exhibit excellent chipping resistance.