JPS58199782A - High speed cutting tip - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an indexable cutting tip particularly suitable for high-speed cutting of steel and cast iron.

In recent years, cutting tips mainly made of A120a have been used for high-speed cutting of steel and cast iron at cutting speeds of 200 to 1000 I/inch. However, high-speed cutting inserts mainly made of AJLzOs have poor impact resistance, so they cannot be used in cutting with large depths of cut or feed, or in interrupted cutting because they tend to break. Therefore, attempts have been made to use 5iaN4, which has excellent impact resistance among ceramic materials, for cutting tips (Japanese Patent Laid-Open No. 55-47276), but the wear resistance of SiaNa is significantly inferior to that of A120a. Therefore, it has not been put to practical use.In addition, a cutting tip in which the surface of a hot-pressed 3i3Na-based sintered body is coated with Al20a and/or Al0N has also been proposed.
5-85481), which can be used for high-speed cutting and interrupted cutting, but the production cost of the hot pressing process, cutting, and polishing process is high, and cutting tips with this substrate coated with AuzOs are not widely used, but it is difficult to put them into practical use. be. Furthermore, the thermal expansion coefficient of Si sNa and AjLzO8 is 3.2X10-6/
The latter was significantly different from 7.8X10-6/'C, and had the drawback of causing peeling of the coating depending on the cutting conditions.

Therefore, the present inventors conducted experiments to eliminate these drawbacks, and developed AJ12011 based on 3i BH3, which is industrially inexpensive and has excellent impact resistance and does not cause damage to the NWA. This was a successful development of a coated cutting tip.

That is, the gist of the present invention is to provide a polyurethane material in which an intermediate layer of aluminum nitride or aluminum oxynitride and an outer layer of aluminum oxide are provided on the surface of a sintered body mainly composed of silicon nitride.
A high-speed cutting tip characterized by a layered structure.

FIG. 1 shows a schematic diagram of the structure of the above-mentioned high-speed cutting tip. Here, 1 is a high-speed cutting tip of the present invention, 2 is a sintered body which is a base body, 3 is an intermediate layer, and 4 is an outer shell.

Here, base silicon nitride, which is the main component of the sintered body, has the chemical formula 3iBNa, aluminum nitride has the chemical formula AIN, and aluminum oxynitride has the chemical formula AjlON.

Aluminum oxide is a substance given by the chemical formula AjlzOs.

The sintered body which is the base of the chip of the present invention has the above-mentioned S as a main component.
If necessary, titanium nitride (chemical formula: TiN) is added to i sNa from 1 to 10 to prevent strength loss and deformation at 148°C.
% (the same applies below weight %). When TiN exceeds 10%, the high toughness of SfaNa is reduced and the fracture resistance during cutting deteriorates, and when it is less than 1%, there is no effect. In addition, as sintering aids, Au20a, yttrium oxide (chemical formula Y20B), lanthanum oxide (chemical formula La20S), zirconium oxide (chemical formula ZrQ2),
One or more selected from dysprosium oxide (chemical formula 1) yzos>, magnesium oxide (chemical formula fvloo), and tantalum oxide (chemical formula Ta2's) is 8
-30% blended, of which AjLzOs-Y20s series, Abun20B-DV'zOs series, AizC) a-Y20
It is preferable to use a sintering aid such as a-DV 208' series, AjLzOB-Ta20s series, or zr 02-Yz Os-MQO series from the viewpoint of ease of sintering and strength of the sintered body.

The above raw materials are provided in the form of powder, and a sintered body is obtained by sintering these various raw materials. With these blends, for example, a sintered body can be obtained as a base consisting of a grain boundary phase containing β-8isNa and TiN having a crystal lattice expanded by the sintering aid. In this case, the TiN phase contained in the sintered body exists at the grain boundaries of β-3i BNm,
If the cutting edge part is exposed to the lagoon during cutting, β-3i・l
This has the effect of preventing deformation of IN4 and preventing a decrease in strength at high temperatures.

In addition, if the sintering aid exceeds 30%, the grain boundary glass phase increases and the original properties of 3i@Nm such as high strength and high toughness are lost, and if it is less than 8%, densification is insufficient and the sintered body This is because pores remain inside and the strength decreases.

General sintering methods such as a hot press method, a cold press (normal pressure sintering) method, and a HIP method can be used for sintering the above-mentioned compound, but among these, the cold press method is preferable from the viewpoint of manufacturing cost. .

In order to form a film of A-stand, A-stand-ON, and AAz08 on the surface of the sintered body, methods such as physical vapor deposition (ion blating, reactive sputtering) and chemical vapor deposition can be used. However, among these methods, the chemical vapor deposition method is preferable from the viewpoint of controlling the constituent elements of the film.

In this chemical vapor deposition method, aluminum chloride (chemical formula: AICJLa) gas and N2 gas are brought into contact with the surface of a sintered body that has been heated in advance by flowing CO2 gas or N2 gas into the surface of the sintered body in a reaction tank. AiN, /IO on the surface of
This is a method of reaction-precipitating N or AizOs, and the reaction m
This is done at 900-1100°C.

Specifically, using the chemical vapor deposition method described above, the method of providing an intermediate layer of A-N or A-ON on the surface of a sintered body and an outer layer of Table A 2011 thereon is as follows.

First, to provide an intermediate layer of AAN or AjlON, A
This is done by contacting the surface of a heated sintered body with a mixture of ACAs gas and N2 gas, or a mixture of N2 gas and CO2 gas.
If only N2 gas is added to the gas and N2 gas, AiN will be precipitated, and if CO2 gas is added in addition to N2 gas, A11ON will be precipitated as an intermediate tone. Next, A9. When a mixture of C1a gas and N2 gas plus only CO2 gas is brought into contact with the surface of the sintered body provided with the intermediate layer, an outer layer of AizOs is precipitated.

In this configuration, the thermal expansion coefficient of Si aNa of the sintered body that is the base is 3.2X10-6/'A201 of the C1 outer layer.
1 has a large difference of 7.8X10-6/'C, but the thermal expansion coefficient of AiN in the intermediate layer is 115.6X between the base and the outer layer.
10/”C, and the layer containing AMON is Al2
The thermal expansion coefficient of a sintered body mainly composed of Si aNa, which has an expanded crystal lattice due to additives in the base body, is 3.8.・~4.2X10=/'C and more Al2O3
Since it is close to , thermal distortion can be dispersed or reduced.

In the above-mentioned method, Gaisho's deposition method adjusts the composition of two types of gases to be brought into contact and deposits on the surface of the sintered body in two stages, forming a discontinuous intermediate layer and an outer layer. AjlN or AAON is deposited on the surface of the sintered body using N2 gas or a combination of N2 gas and CO2 gas for A1C15 gas and H2 gas, and then the proportion of N2 gas is continuously decreased, and CO2 gas By increasing the ratio of , it is possible to form a layer in which the nitrogen component in the intermediate layer continuously decreases outward and the oxygen component increases accordingly, and the middle layer and outer layer become continuous. It is also possible to provide such a configuration. If the composition changes continuously like this, it's hot!
Since the thermal strain caused by the distance of the optometry is distributed throughout the entire earthquake, it is more difficult to be destroyed by thermal strain than the discontinuous layer described above.

When providing discontinuous layers, the thickness of the intermediate layer is 0°01 to 3
The thickness of the outer layer is preferably set to 0.5 to 2 μ from the viewpoint of wear resistance and peeling resistance during cutting. In addition, regardless of whether it is continuous or discontinuous, it is preferable to set the overall thickness to 0.5 to 5 μm, and preferably 1 to 4 μm from the viewpoint of cutting life. If the thickness of the intermediate layer and the outer layer is too thick, cracks will easily form between the sintered body and the coating due to thermal shock, which may cause chipping of the cutting edge during cutting. has little effect on wear resistance, etc.

As detailed above, the high-speed cutting tip of the present invention is made of Si.
AiN or Al0 is applied to the surface of the sintered body mainly composed of 3N4.
By creating a multilayer structure with an intermediate layer of N and an outer layer of AAzOs on top of it, the actual cutting edge becomes Al2O, exhibiting good high-speed machinability, wear resistance, and chipping resistance. Since the solid body is 3i aNa, it exhibits good impact resistance, and furthermore, a medium wall I is formed between the Al2O5 layer and the 5fsNa of the substrate, which has a thermal expansion coefficient that is approximately the middle value of the respective thermal expansion coefficients. This makes it possible to prevent the occurrence of cracks due to differences in thermal expansion, resulting in a long-life cutting tip.

Next, a more specific explanation will be given using examples.

Example 1 Si sNa (purity 96.5% average particle size 0.5μ) 8
0% Y2O3 (purity 99.9% average particle size 1.2μ) 10% AAzOs (purity 99.9% average particle size 1.0μ) 5% TiN (purity 99.2% average particle size 1.0μ) 5% Put the above ingredients into an AAzOs ball mill together with A120a balls and alcohol such as ethyl alcohol,
The mixture was mixed in the dark for 20 minutes and dried. Thereafter, 4% paraffin was added, and press molding was performed using a mold so that the sintered body 1 became a rectangular parallelepiped of 13ssx1311x51-. Sintering is N2
The test was carried out at 1750° C. for 1 hour in an atmosphere. A transverse rupture test piece was cut out from this sintered body, and the transverse rupture strength was measured at a span length of 10-1 and found to be 95 ko/ll. This test piece was 5NGN433, chamfer-0.05s+ex2
5-", this was processed into a substrate using CVD (chemical vapor deposition method) and heated to 1050°C in a reaction vessel, and 80 particles were passed through an aluminum chip kept at a temperature of 320°C. A mixed gas of 17% by volume and HC1, 5% by volume of CO2 gas, 71% by volume of T12 gas, and 7% by volume of N2 gas were flowed and held for 5 hours.The flow rate of N2 gas was changed every hour. The supply of N2 gas was eventually stopped.

The thickness of the resulting coating layer was 2.4μ, and an X-ray microanalyzer showed that the nitrogen component concentration decreased stepwise from the inside to the outside, as shown by 8 in Figure 3. Confirmed by line analysis.

Using the tip of Example 1, a cutting test was conducted on a high nickel alloy (Inconel 718), which is considered to be an extremely difficult-to-cut material. Cutting conditions are cutting speed 200m/1n, depth of cut 1.5IllIll, and feed rate 0.15 mm/r.
Cutting was performed under ev conditions until the cutting edge was damaged.

As a result, the cutting tip of the present invention was capable of cutting for 865 minutes, whereas the cutting tip of the comparative example, which was a sintered body manufactured in the same manner as the example and without an intermediate layer and no outer layer, was able to cut for 2 minutes, and the cutting tip of the commercially available Δ1
The 20s series ceramic tool broke in 1 minute, and the commercially available AnzOa-coated carbide tip broke in 30 seconds.

Example 2 A mixed gas of AlC1a gas and H(it gas), a sintered body of CO2 gas, N2 gas, and N2 gas for forming the intermediate layer and the outer layer in the chip manufacturing method in Example 1. Chips with different thicknesses of the intermediate layer and outer layer were obtained by changing only the contact time to the surface.The nitrogen content of the coating layer was 8 in Fig. 3.
It had two layers like this.

The above chips were subjected to the same cutting tests as were performed on the chips of Example 1 above. The results are shown in FIG. The vertical axis represents the cutting time until breakage (minutes), and the horizontal axis represents the thickness (μ) of the coating layer including the intermediate layer and the outer layer. Here, it can be seen that the cutting time is the longest when the thickness of the target t+ii is about 2μ. In addition, the range in which the cutting time is approximately twice as long as that without WIN is the thickness of the HIM of 0.5 to 5μ, and in particular, the thickness of 1 to 4μ is three times or more, resulting in better performance. be.

Example 3 The same substrate as in Example 1 was placed in a CVD reaction vessel at 1050°C.
A10 sentence 3 and HC generated by passing HCM through an aluminum chip that was heated to 320℃ and kept at a temperature of 320℃.
Mixed gas: 17% by volume and 1% by volume of 112 gas are kept constant, and the remaining 12% by volume of CO2 + N2 mixed gas is converted to CO2 in 3 hours from 6% by volume of CO2 and 6% by volume of N2 by continuous operation of the valve. : 12 volume% and N2: 0 volume%
The final composition was maintained for 1 hour. The thickness of the coating layer thus obtained was 2μ, and the thickness of the third layer was 2μ.
As shown by C in the figure, the nitrogen component from the inside to 15μ has a continuous concentration gradient from the inside to the outside.
It was confirmed that μ is AjlzOall.

As a result of conducting the same cutting test as in Example 1 using the tip of Example 3, the cutting time was approximately 10% longer than that of the tip of Example 1.

Example 4 In the same manner as in Example 1, Y2O11: 10%, Al
2O:l:5% and TiN with different blending ratios were
The transverse rupture strength of the mixture mixed with iaNa and sintered was measured.

The results are shown in Table 1 along with the blending ratio of TiN.

As is clear from these results, it was found that the chips with this formulation exhibited sufficiently high transverse rupture strength, especially when the TiN formulation was 1 to 1.
At 10%, it showed outstanding transverse rupture strength in both normal temperature transverse rupture strength and 1200°C transverse rupture strength.

Example 5 3i3Na sintered body with various sintering aids added to 5NGN4
33. Chamfer - 0.111 x 25° As is clear from the results, the chip with this formulation shows sufficiently high fracture resistance, and especially when the sintering aid content is 8 to 30%, it has outstanding fracture resistance. Indicated.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a high-speed cutting tip of the present invention;
Figure 2 is a graph showing the relationship between the thickness of workpiece III and cutting time (cutting life), and Figure 3 is a schematic graph showing the change in the proportion of N (nitrogen) component of workpiece 111i. I. 1... High-speed cutting tip of the present invention 2... Substrate (sintered body) 3... Intermediate layer 4... Outer layer agent Patent attorney Tsutomu Adachi Figure 1 Figure 2 0123456 Supplementary 1jl172 (μ)

Claims (1)

[Claims] 1. A multilayer structure in which an intermediate layer of aluminum nitride or aluminum oxynitride and an outer layer of aluminum oxide are provided on the surface of a sintered body mainly composed of silicon nitride. Tip for high speed cutting. 2. The high-speed cutting tip according to claim 1, wherein the nitrogen component of the intermediate layer decreases outward, and the oxygen component increases accordingly, so that the intermediate layer and the outer layer form a continuous layer. 3. A sintered body containing nitride as a main component is a sintered body containing 1 to 10% by weight of titanium nitride in nitride powder selected from aluminum oxide, yttrium oxide, lanthanum oxide, zirconium oxide, dysprosium oxide, magnesium oxide, and tantalum oxide. The high-speed cutting tip according to claim 1 or 2, which is a sintered body containing 8 to 30% by weight of one or more of the following.