JP2529190B2 - Coated cemented carbide - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a highly reliable, high performance and highly reliable coated cemented carbide cutting tool.

[Technical background] One or two or more kinds of carbides and / or nitrides of one or more kinds of metals of group IVa, Va, VIa of the Periodic Table, mainly one or two kinds of metals of iron group above A cemented carbide with a cemented carbide that is bonded with more than one kind as the base material and a ceramics such as TiC, TiN, Al ₂ O ₃ coated on it for 5 to 15μ is the toughness of the base material and the wear resistance of the surface material. It is widely used in practice as a cutting tool with excellent properties. In particular coated cemented carbide coated with Al ₂ O ₃ has excellent oxidation resistance of Al ₂ O _3, since the resistance to reactivity with steel, which can withstand a higher speed cutting when compared with the conventional cutting tool, It is put into practical use as a cutting tool in response to the demand for higher efficiency in the industrial world.

However, while the demand for higher efficiency in the industrial world is increasing, there is a demand for cutting tools that can withstand even higher speed cutting.

In coating cemented carbide coated with Al ₂ O _3, but it can withstand a higher speed cutting when the thickness of the Al ₂ O ₃ film thickness is that which is well known At a person skilled in the art, Al ₂ O ₃ is Since it is significantly brittle as compared with the cemented carbide that is the base material, there is a natural limit to increasing the film thickness of Al ₂ O ₃ , and the limit is 5 to 6 μ at most. The present invention aims to provide a cutting tool material that overcomes the brittleness of Al ₂ O ₃ and can withstand higher speeds.

DISCLOSURE OF THE INVENTION Since Al ₂ O ₃ is excellent in oxidation resistance and reaction resistance with steel, a ceramic tool made by sintering Al ₂ O ₃ has been developed for a long time. However, since this Al ₂ O ₃ ceramics tool was extremely weak against thermal shock and thermal fatigue, it could hardly be used practically. Therefore, various improvements have been added, and it is known that when about 30% of TiC is dispersed in Al ₂ O ₃ , the thermal shock resistance, thermal fatigue resistance and toughness are remarkably improved.

Therefore, the inventor has examined whether this idea can be applied to coated cemented carbide. However, Al ₂ O ₃ is used in chemical vapor deposition and physical vapor deposition, which are the usual methods for producing coated cemented carbide.
It was almost impossible to coat a mixed material of TiC and TiC. This is because the metal titanium has a very high affinity with oxygen, and even if an attempt is made to coat a mixed substance of Al ₂ O ₃ and TiC, only oxides of Al ₂ O ₃ and Ti can be actually formed. Therefore, the inventors have a result of various studies, that the same effect when dispersing TiC in Al ₂ O ₃ is obtained by alternately stacking a very thin film (preferably 100Å or less) of Al ₂ O ₃ and TiC Got amazing findings. It should be noted that when the film thickness of each layer constituting this stack exceeds 100Å, this effect is hardly observed. And how about Al ₂ O ₃ and T
Even if the strength of the coating film is improved by laminating a thin layer of iC, if the total film thickness exceeds 20 μ, the strength of the coated cemented carbide is significantly decreased, which is not preferable. The total film thickness is 1μ
In the following cases, the effect of coating was not recognized, which was not preferable.

It should be noted that the present invention is based on the surprising finding that the extremely thin (100 Å or less) thin layers of two substances are alternately laminated and coated, and in fact, it has the same effect as dispersing the particles of the two substances. Al ₂ O ₃ is used as the material that constitutes the film
Needless to say, it is not limited to TiC.

Combinations such as TiN and TiC give good results.

However substance over Al ₂ O ₃ considering the high-speed cutting is difficult to obtain, consisting Ti, Zr, and Hf in order to improve the brittleness of Al ₂ O ₃ is a material to be laminated alternately with Al ₂ O ₃ Most preferred is one or more compounds consisting of one or more metal elements selected from the group and one or more metal elements selected from B, C, N and O. Note that it is preferable to provide TiC as an adhesive layer as the intermediate layer. The thickness of the hard film composed of the intermediate layer and the alternately laminated coating layer is preferably 1 to 20 μm.

 The present invention is described in detail below with reference to examples.

Example 1 ISOM-10 cemented carbide base material (model number CNMG 433 ENZ) was added to TiCl ₄ ,
1000 ° C in a reaction vessel in which a mixed gas of CH ₄ and H ₂ was passed at 20 Torr
After coating with TiC for 3μ as an intermediate layer, the temperature is lowered to 700 ° C, and a mixed air stream of AlCl ₃ , CO ₂ and H _{2 is} flowed at 1.5 Torr, and Al ₂ O ₃ is coated at 85 Å. ₄ , NH ₃ , H ₂
The mixed air flow was made to flow at 1.5 Torr and TiN was also coated at 85Å.

This Al ₂ O ₃ 85Å, TiN 85Å coating operation was repeated to coat 7 μm of the Al ₂ O ₃ / TiN alternating laminated layer. After cooling, the sample was examined by X-ray diffraction, and it was confirmed from the position of the satellite peak that Al ₂ O ₃ and TiN were alternately laminated at about 85 Å.

This sample is designated as A. For comparison, TiC is 8μ on the same base material,
Al ₂ O ₃ coated with 2μ B, TiC 5μ, Al ₂ O ₃ 5μ
The coated material was designated as C and a cutting test was conducted under the following conditions.

Cutting conditions (1) Work material: SCM435 (H _B = 250) Cutting speed: 300m / min Feed: 0.40mm / rev Depth of cut: 2mm Holder: PCLNR2525-43 Cutting agent: Water-soluble cutting agent A is cut for 15 minutes The flank wear was 0.38 mm, while B was able to cut only 1 minute 15 seconds and C was only 5 minutes 38 seconds.

Cutting conditions (2) Work material: SCM435 (H _B = 250) 4-groove material Cutting speed: 150m / min Feed: 0.28mm / rev Depth of cut: 2mm Holder: PCLNR2525-43 Cutting agent: Not used Cutting time: 30 seconds 100 cutting edges were cut, and A had 14 missing edges, while B had 12
The cutting edge, C, was missing 35 cutting edges.

Cutting conditions (3) Work material: SCM435 (H _B = 250) Forged round bar 50 x 150 Cutting speed: 300m / min Feed: 0.40mm / rev Depth of cut: 1.5-3mm Holder: PCLNR2525-43 Cutting agent: Water-soluble cutting Use agent Cutting time: 11 seconds A was able to cut 80 pieces, whereas B was 8 pieces and C was 7 pieces
I could only cut books.

Example 2 The same base material as in Example 1 was coated with 3 μm of TiC as an intermediate layer by the same method (85 Å alternately laminated), and then Al ₂ O ₃ / TiN
The total thickness is 1 by repeating alternating layers.
Samples prepared by coating μ, 3μ, 10μ, 15μ, 20μ with D, E, F, G,
Tested under the cutting conditions (3) of Example 1 as H and I. D was 7, E was 24, F was 78, G was 77, and H was 72.
Four books and I have been scraped. (I is a comparative example) Example 3 The same base material as in Example 1 was coated with 3 μm of TiC by the same method, and then the Al ₂ O ₃ / TiN laminated film was used, but the unit layer thickness was 50Å, 80Å, 1
When samples of 50 Å and 500 Å coated with 7 μ were J, K, L and M, and tested under cutting conditions (3) of Example 1,
102 and K were cut 98 but L was 32 and M was 7 and could not be cut. (L and M are comparative examples) Example 4 Same method as in Example 1 but with the same method (alternating lamination of 80Å)
After coating 3 μm of TiC as an intermediate layer, 7 μm of the alternate layered structure having the structure shown in Table 1 was coated.

Table 1 shows the results of testing this sample under the cutting conditions (3) of Example 1.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Nomura 1-1-1 Kunyokita, Itami City Sumitomo Electric Industries, Ltd. Itami Works (56) Reference JP-A-57-120667 (JP, A) 55-145165 (JP, A) JP-A-52-105396 (JP, A)

Claims (1)

(57) [Claims] Claims: 1. One or more carbides and / or nitrides of one or more metals of group IVa, Va, VIa of the periodic table and one or more of iron group metals. Is a cemented carbide with a hard metal of 1 to 20 μm coated on its surface as a base material, and the hard film is composed of an intermediate layer and an alternate laminated coating film, and a TiC coating as an intermediate layer. It has a covering film and an alternating laminated coating film is formed on the surface thereof, and the alternating laminated coating film is an Al ₂ O ₃ coating film and TiN, TiC, ZrN, HfC, ZrO ₂ , TiBN, TiCO A coated cemented carbide characterized by comprising one or a combination of two or more coating films selected from the above, wherein the coating films constituting the alternately laminated coating layers have the same film thickness of 100Å or less.