Stock material or miscellaneous articles – Self-sustaining carbon mass or layer with impregnant or...
Reexamination Certificate
1999-10-19
2002-04-30
Turner, Archene (Department: 1775)
Stock material or miscellaneous articles
Self-sustaining carbon mass or layer with impregnant or...
C428S697000, C428S698000, C428S699000, C428S701000, C428S702000, C428S704000
Reexamination Certificate
active
06379798
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a laminated coated-material to be used for a cutting tool. More specifically, the present invention relates to a laminated coated-material in which each corner of the cutting blade for a cutting tool is coated by multi layers to easily identify whether it has been used for cutting processing or not.
2. Prior Art
In a tool made of a hard alloy having a coated layer, a decorative colored layer is provided at the outermost layer of the coated layer to identify the used cutting blade corner so that the used layer is identified whether the colored layer is peeled off or not. As the decorative colored layer, titanium nitride which appears a gold color or titanium carbonitride which appears a yellow color to red color depending on the content of nitrogen (see Japanese Provisional Patent Publication No. 66513/1974). Incidentally, in the present specification, the decorative colored system means a system that appears a color phase other than neutral color system such as white to black color.
However, in the cutting tool having such a titanium compound as an outermost layer, said titanium compound reacts with a material to be cut and said material to be cut is tend to be adhered or welded (the term “adhesion” in the specification includes adhesion by pressure or temperature, and also includes “seizure”) to the cutting blade of the cutting tool. Thus, in the coated cutting tool, processing precision of the material to be cut is decreased due to adhere or weld and cutting operation cannot be continued and becomes impossible due to wear and adhesion or weld of the cutting blade during the cutting operation. When the outermost layer of the coated cutting tool is constituted by Al
2
O
3
having a low reactivity with the material to be cut, the above-mentioned problems can be solved but the outermost layer appears a black color to a color near to black so that it is difficult or impossible to identify the portion of the used cutting blade corner.
Thus, various methods have been proposed to realize identification of the used cutting blade corner and to prevent the above-mentioned adhesion or weld.
In Japanese Provisional Patent Publication No. 52603/1996, there is disclosed a method of constituting the outermost layer at a ridge portion of the cutting blade of a cutting tool by aluminum oxide and the portion other than the outermost layer by a titanium type ceramics represented by the formula: Ti(C
x
N
y
O
z
) (wherein 0≦x, y, z≦1). However, this method requires many steps so that it is also disadvantageous in economy.
In Japanese Provisional Patent Publication No. 2227703/1995, there is disclosed a method in which the outermost layer of a cutting tool is made aluminum oxide and a layer immediately under the outermost layer is made titanium nitride. According to this method, the above-mentioned problems can be solved but the color tone of the tool is poor and commercial value is inferior.
In Japanese Provisional Patent Publication No. 73802/1955, there is disclosed a method in which the outermost layer of a cutting tool is constituted by titanium nitride and the surface of which is made smooth whereby weld of the material to be cut can be prevented. However, according to this method, not only the steps are increased but also the weld preventing effect is insufficient.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-mentioned problems and to provide a laminated coated-material for cutting tool which is excellent in adhesion or weld preventing effect without increasing steps, is possible to identify the corner of a cutting blade to be used, and has an appearance with a high commercial value wherein the color tone of which is a gold color.
The present inventors have carried out intensive studies to accomplish the above objects, and as a result, they have found that the objects can be accomplished by so constituting the outermost layer of a cutting tool having a color that it is peeled off by mechanical stress. When the outermost layer of a cutting blade to be used for cutting is peeled off by mechanical stress, adhesion or weld of a material to be cut can be prevented and a layer having a color tone of a neutral color such as an aluminum oxide layer is exposed whereby the portion which had been used can be easily identified.
That is, the present invention relates to a laminated coated-material for cutting tool which comprises a laminated coated-sintered alloy in which on the surface of a substrate comprising a hard alloy or a cermet at least two layers containing an inner layer comprising aluminum oxide and positioned at said substrate side, and an outermost layer having a decorative color and positioned at the far most side of said substrate, and said outermost layer is so coated that it is peeled off by mechanical stress.
In the present invention, the upper limit of the adhesive force is that peeling of the outermost layer occurs at the portion of the surroundings at which an indenter is contacted when 588 N (60 kgf) of load is applied to the test piece by using Rockwell hardness testing machine. The lower limit of the same is not specifically limited and a material can be used if it is identifiable before and after the use whereas if the outermost layer peeled off only by wiping a hand or a cloth, it cannot be practically used.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, the present invention is described in detail.
The substrate to be used for the laminated coated-material for a cutting tool of the present invention comprises a hard alloy or a cermet. Such a substrate is a sintered alloy having high hardness and obtained by sintering at least one material selected from the group consisting of a carbide, a nitride and a solid solution of a metal of Group 4 to Group 6 of the Periodic Table, and at least one metal selected from the group consisting of iron, nickel and cobalt. Among these materials, the hard alloy may include, for example, WC—Co, WC—TaC—Co, WC—TiC—Co, WC—TiC—TaC—Co, etc. As the cermet, there may be mentioned, for example, a titanium carbide series cermet such as TiC—Ni, TiC—Ni—Cr, TiC—Ni—W, TiC—Co, TiC—Co—Cr, etc.; and a titanium carbonitride series cermet containing nitrogen in the above-mentioned titanium carbide series cermet.
Of these, preferred is a hard alloy comprising 3 to 10% by weight of a binder phase mainly comprising cobalt and/or nickel, and the reminder being a hard phase mainly comprising tungsten carbide.
The laminated coated-material of the present invention is constituted by the above-mentioned substrate, and a coated portion in which at least one part of the surface, particularly a plural number of surfaces containing a plural number of corners of a cutting blade is covered by a coating layer in which a plural number of films is laminated. Said coated portion contains an inner layer positioned at said substrate side and an outermost layer which is farthest from said substrate, and if necessary, at least one of a subbing layer between the substrate and the inner layer and an intermediate layer between the inner layer and the outermost layer may be provided.
The inner layer comprises aluminum oxide. The thickness of said inner layer is not particularly limited, and preferably within the range of 0.1 to 10.0 &mgr;m, more preferably 0.5 to 6.0 &mgr;m. The surface of the inner layer preferably has an average surface roughness represented by the depth of unevenness of said surface observed at the perpendicular section to said surface of 0.6 &mgr;m or less.
The outermost layer has a decorative color tone, and may preferably comprise titanium nitride, titanium nitroxide, titanium carbonitride, titanium carbonitroxide, zirconium nitride, (titanium-aluminum)nitride, (titanium-aluminum)nitrocarbide, (titanium-aluminum) carboxide, etc. Among these, the outermost layer preferably comprises titanium nitride, titanium nitroxide, zirconium nitride and zirconium nitroxide since they have bright color tone and are easily identifiable at the u
Foley & Lardner
Toshiba Tungaloy Co., Ltd.
Turner Archene
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