JPS6274076A - Production of multi-layer coated hard alloy - Google Patents

Abstract

PURPOSE:To form a coating for high-speed cutting having excellent toughness and wear resistance on the surface of a sintered hard alloy material by coating the surface of said material with the carbide or nitride of a specific metal and the oxide of a specific element contg. >=1 kinds among V, P and B and heating the same in a vacuum or gaseous halogen. CONSTITUTION:The hard film consisting of the hard carbide or nitride of >=1 kinds selected from the group 4a, 5a, 6a metal of periodic table and B and the hard oxide such as TiO2, ZrO2 or Al2O3 is coated on the surface of a cutting tool consisting of a sintered hard alloy, cermet, ceramics, etc. having high hardness. The oxide layer of Al2O3 and V is formed thereon in succession thereto and Al2O3 and the oxide layer of B are formed. Such tool is heated to 1,100-1,400 deg.C in a vacuum or gaseous halogen such as HCl or reducing atmosphere to coat the hard Al2O3 layer on the surface, by which the wear resistance of the cutting tool is improved and the service life is extended.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to coated tools for high speed cutting.

[Background of conventional technology]

Fe, Go,
The base material is a cemented carbide bonded with one or more metals selected from the group consisting of Ni, Cr, -〇, -, or ceramic, and the surface is coated with aluminum oxide, titanium carbide,
Coated cemented carbide, which is made by coating one or more layers of ¥II film made of titanium nitride or the like with a thickness of 5 to 10μ, has a material that combines the toughness of the base material and the wear resistance of the surface coating layer. As a material, it is widely used in place of conventional cemented carbide cutting tool materials.

Particularly in recent years, interest in tool materials suitable for high-speed cutting has been rapidly increasing in the actual industry, partly due to the pursuit of cost reduction.
Starting with coatings such as iN, there is a shift to aluminum oxide coatings, which are more suitable for high-speed cutting.

[Problems to be Solved by the Invention] However, coated cemented carbide coated with aluminum oxide has a coating thickness of 5 to 15 μm for titanium carbide, whereas the coating thickness of aluminum oxide is 5 to 15 μm. Film thickness is 1.0~4
．． It remained at about 0μ.

The reason for this is thought to be that the toughness of alumina is inferior to that of TiC, and in addition, unlike TiC, alumina film cannot be coated uniformly over the entire cutting tip.

That is, the alumina film is several times thicker at the edge of the cutting edge than at other parts, and as a result, the average alumina film remains at most 4 μm thick. The object of the present invention is to provide a method for uniformly coating alumina with a thickness of 3 to 10 μm.

[Means for solving problems]

In order to solve the above-mentioned □ problem, the inventor made various studies and, as a result, dissolved one or more of V, P, and B in an alumina film as a solid solution, and then in a vacuum or halogen gas at 1100 to 1400°C. Alternatively, it has been found that heat treatment can be performed in a reducing atmosphere. These oxides of V, I'', and B form a solid solution in Al2O:l to form a compound of Al2, which forms a liquid phase at a relatively low temperature after 1000''Ci'iii. This is thought to be due to the fact that mass transfer on the surface becomes extremely active through this liquid phase, and the difference in growth rate between the cutting edge ridge and other parts is alleviated. Furthermore, V,
Alumina is divided using P and B carbides, nitrides, or their compounds as an intermediate layer.

We discovered that it is sufficient to adopt a multilayer structure.

These intermediate layers absorb some of the V, P, and B in alumina and grow, so they have good adhesion to alumina and are excellent in strength, so they are effective in improving the toughness of alumina.

On the other hand, the presence of such substances lowers the heat resistance of alumina, so during or after the production process of each coating film constituting this structure, the coating film is heated in a vacuum or in a halogen gas at a temperature of 1100 to 1400°C. It has also been found that heat treatment can be performed in a reducing atmosphere to reduce L P and B in alumina.

When heated at 1100 to 1400°C in a halogen gas such as l1c1, or in a reducing atmosphere such as Therefore, the heat resistance of the film can be improved. Furthermore, if heat treatment is performed in a vacuum during or after the intermediate layer generation process, V, P, and B will diffuse into the intermediate layer from within the alumina and the concentration in the alumina will decrease. It has the effect of improving heat resistance. ' Below 1lOO℃, ν.

If the diffusion of P and B is slow and exceeds 1400°C, the hard phase of the base material will become coarse, which is not preferable.

Although only alumina has been described above, the same effect can be obtained when Ti or Zr oxide is dissolved in alumina.

According to the present invention, since it is possible to uniformly coat the alumina film with a thickness exceeding 4 μm, it is possible to provide a tool that has good fracture resistance and is capable of high-speed cutting.

Example 1 A cemented carbide consisting of 85% by weight - ○, 10% by weight (Ti, Ta, W)C and 5% by weight Co was heated at 1000°C with
TiCj4 and C1+ with capacity χ, remaining) 1□ Ti from gas
After C3, c1m coating, 5 capacitance χU as the second layer
a,, S volume, 5iχCO2゜5 volume I VCl, remaining 1
1. Oxide layer of A/zO, and V 1 μm in gas
After that, 5 volumes χ-(~shiVcf, 50 volumes Mzsz, remaining H2 medium te VNwo:)
--r I: /I, after heating in lIC7 gas at 1100°C, 5 volumes χ u cl s, 5 volumes χ as the fourth layer
B (Jx, 5 volume 1xco2, 11□ remaining ^!20.
2 ttm of B oxide layer was produced, and then heated in the same manner in a crushed atmosphere. After this, 5 volumes of BCI, , and Ti(J
, and sz, r (lh/N2 =
1) Generate Ti (BN) and as the final layer, 5 capacitance χ
AI C1z, 0, 1 capacity! Pc1t5 amount crab χCO
7 Remaining 11□ Gas Cross section of this coating chip IJ1i
When observing t, the difference in the alumino film thickness between the ridgeline of the cutting edge and other parts was small, and the difference was twice as large in the case not according to the present invention. Cutting speed of these chips is 300m/
SC at min feed 0.30mm/rev, depth of cut 211Im? Cutting tests were carried out on I 435 (II, 1280).

The product of the present invention took 12 minutes to reach V of 0.30 mm, while the product not according to the present invention experienced abnormal wear in 1 minute.

Claims (1)

[Claims] (1) Using cemented carbide, cermet, or ceramic as a base material, one or more carbides and/or nitrides selected from the group consisting of IVa, Va, and VIa group metals and B are added to the surface of the base material. V, V,
The oxide film contains one or more of P and B, and the oxide film contains V, P,
It is divided by an intermediate layer consisting of a solid solution or a compound or a mixture containing one or more of B. During or after each coating step, at a temperature of 1100 to 1400 ° C. in vacuum or in a halogen gas or , a method for producing a multi-layer coated hard alloy, characterized by carrying out heat treatment in a reducing atmosphere.