JPS58136766A - Surface-coated sintered hard alloy member - Google Patents

Abstract

PURPOSE:To obtain a sintered hard alloy member with superior wear resistance and considerably improved chipping resistance by coating the surface of a sintered hard alloy substrate with a specified hard substance with superior wear resistance and by forming a metallic Ti layer at the uppermost part. CONSTITUTION:The surface of a sintered hard alloy substrate is coated with a single layer of 1 kind of component or a multiple layer of >=2 kinds of components selected from the carbides, nitrides and oxides of the IVa, Va and VIa group metals in the periodic table, Al, Si and B and solid solns. each consisting of >=2 kinds of said compounds. The tickness of the layer is adjusted to 1- 15mum. A metallic Ti layer is then formed at the uppermost part in 0.1-5mum thickness. Thus, a coated sintered hard alloy with high wear and mechanical impact resistances is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to coatings on cemented carbide surfaces.

Coating members in which the surface of cemented carbide is coated with various hard substances have significantly improved -C wear resistance compared to conventional cemented carbide, and are currently being used by people.

However, since the surface coating layer does not contain a binder metal, cracks easily occur in the coating layer, and the cracks cause fM and failure to proceed.

Therefore, it is difficult to avoid the drawback that the coated member is more easily damaged than conventional cemented carbide.

It is an object of the present invention to improve the above-mentioned drawbacks of the prior art and to provide a novel surface-coated carbide member that has excellent blood t I* resistance and greatly improved fracture resistance.

The feature of the present invention is that each Al hard material with excellent wear resistance is coated on a cemented carbide, and the top layer is coated with '1'11'1 metal.゛1゛1 Metals are naturally hard substances such as carbides and nitrides.
It becomes possible to reduce the occurrence of scratches from the top surface of the coating. Therefore, fracture resistance is greatly improved compared to the case where only a conventional hard material is coated. Furthermore, Ti is easy to form oxides, and the resulting oxides have excellent wear resistance, so there is no possibility that the wear resistance will deteriorate compared to those coated with only a hard material. do not have.

Here, the lower hard layer is 4a and 5a16 of the periodic table.
A single layer of one of the group consisting of Group A metals, carbides, nitrides, and oxides of AI, Si, and H, and solid solutions of two or more of these, or a multiple layer of 1 m consisting of Id2 loincloth or more has the highest wear. Excellent sex. The thickness of the lower layer is 1
~15 μm is desirable. If it is less than 1 μm, no coating effect will be obtained, and if it exceeds 15 μm, cracks will easily occur and the frequency of breakage will be low.

The top metal coating is preferably Ti for the above reasons.
The thickness of the i-coating layer is preferably 0.61 to 5 μm.

0.1μ! If it is less than n, the effect of improving fracture resistance cannot be obtained. If the thickness exceeds 5 .mu.m, the metal properties become noticeable, causing plastic changes in the surface of the substrate and deteriorating the wear resistance.

Example 1 The surface of a P50 cemented carbide was coated with TiC to a thickness of 5 μm, and further coated with TiQ to a thickness of 2 μm (A chip). On the other hand, a chip coated only with TiC to a thickness of 7 μm was used for comparison (chip B). A cutting test was conducted using these chips under the following conditions.

Cutting material SCM5 (Hardness HsilO) 10mm wide groove Cutting speed 15om/min Feed 0.5mm/rev Depth of cut 2-Chip shape 5NuN432 The B tip of the comparison product broke and could only cut for 1 minute. In contrast [2, the tip of the present invention did not break even after cutting for 15 minutes and good cutting performance was obtained.

Example 2 TiC3z+m, A from the bottom layer on the P20 cemented carbide surface
A coated tool coated with 2 μm of IzOx and 3 μnl of Ti metal was prepared (C chip). On the other hand, TiC5am
, A comparative material was one coated with only 2 μm of A1zOs (D chip). A milling test was conducted using these chips under the following conditions.

Work material 80M3 (Hardness I (s40) Cutting speed 2oom/min Feed 0.25-/Blade depth of cut 2-Tip shape SPK 42TR The comparison product D chip broke in 50 seconds, but the inventive C chip broke in 20 seconds. Good cutting performance was obtained with no damage during cutting.

By coating the cemented carbide substrate with a hard substance and further coating the top layer with the 'v1 metal, a coated cemented carbide having high wear resistance and mechanical impact can be obtained.

Agent Hisanori Dechu 4,

Claims (1)

[Claims] 4a, 5a and 6 of the periodic table on the surface of the cemented carbide substrate.
A film consisting of a single layer or a multilayer of two or more of the group consisting of group a metals, carbides, nitrides and oxides of AI, 8i, i- and B, and solid solutions of two or more of these. 4, a 15 μm coating layer was formed on the top layer, and a Ti layer was added on top.
A surface-clear cemented carbide member coated with a metal layer of 0.1 to 5 μm.