JPH09267204A - Hard metal tool member having strong edge line part and surface-covered hard metal tool member for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard metal tool member having a strong laminated part showing excellent tenaciousness, breakage resisting property and chipping resisting property, and a cover hard metal tool member. SOLUTION: Polyhedral hard metal member comprises 3-15wt.% of a bonding phase having Co as the main component, 3-30wt.% of cubic system compound consisting of at least one kind of compound carbonitride, compound carbooxide and compound carbonitrooxide of W and Ti and residuals of tungsten carbide and inevitable impuriyies, and is formed with a surface layer having 3-30μm of depth ranging from the surface of the hard metal member to the inside and substantially consisting of the tungsten carbide and bonding phase. The surface layer is the hard metal tool member formed uniformly up to the edge line part of the polyhedral hard metal member. The hard metal member has the tenacious edge line part containing 0.02-0.2wt.% of oxygen and/or nitrogen for the whole hard metal member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cemented carbide tool member and a coated cemented carbide tool member having a tough ridge line portion exhibiting excellent toughness, fracture resistance and chipping resistance, and particularly to intermittent turning and milling of steel. The present invention relates to a cemented carbide tool member and a coated cemented carbide tool member having a tough ridge having a tough layer at the cutting edge that exhibits a long life when used for cutting.

[0002]

2. Description of the Related Art Generally, a cemented carbide cutting tool is required to have improved wear resistance as well as fracture resistance and chipping resistance. In particular, it is an important issue in intermittent turning and milling of steel. Has become.

As one measure for this improvement, a fracture resistance is improved by providing a surface layer of tungsten carbide and the binder phase near the surface of WC-cubic compound-Co cemented carbide. Various cemented carbides and coated cemented carbides have been proposed. Among coated cemented carbides having such a surface layer, a coated cemented carbide with a further improved fracture resistance is proposed by forming a similar surface layer on the traverse portion which becomes the cutting edge, and a method for producing the same. Has been done. A typical example is JP-A-6-73560.

[0004]

Japanese Patent Laid-Open No. 6-73560, which is a prior art, discloses that in a cemented carbide consisting of WC-cubic compound-iron group metal, the cubic compound is Z
A surface layer containing at least one selected from carbides, nitrides, carbonitrides, and carbonates of r and / or Hf and WC, and the outermost surface of the twill line portion serving as the cutting edge, which is composed only of WC and an iron group metal. Disclosed is a coated cemented carbide using a base material having an alloy and a method for producing the same.

In the coated cemented carbide disclosed in the above publication, the base material is WC-cubic compound-iron group metal-based cemented carbide,
A surface layer consisting only of WC and an iron-group metal is formed on this base material, and this surface layer is formed up to the traverse line portion serving as a cutting edge, but Z is an essential component for forming a cubic compound.
Since it contains carbides such as r and / or Hf, it becomes difficult to sinter, and a large amount of cavities are easily generated in the alloy, resulting in a significant decrease in strength, and Zr in the binder phase of the iron group metal. , Hf are solid-dissolved and the toughness tends to decrease, and therefore the variations in the various characteristics of the alloy become large, and Zr and Hf are expensive.

The present invention has solved the above-mentioned problems. Specifically, the content of nitrogen and / or oxygen is limited, and a complex carbonitride or complex carbonate of Ti and W is obtained. , Forming a cubic compound composed of complex carbonitride oxide, limiting Ta and / or Nb in the cubic compound as much as possible, and cutting line as a cutting edge A cemented carbide tool member having a tough ridge line portion and a coating thereof, in which a decrease in strength and toughness is prevented and a variation in various characteristics is reduced by uniformly forming a surface layer composed of tungsten carbide and a binder phase It is intended to provide a cemented carbide tool member.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have developed a cemented carbide and a cemented carbide thereof for a long period of time, in which a surface layer containing no cubic compound is uniformly formed in the twill line portion. We have been studying to minimize the variation in various characteristics. However, by limiting the content of nitrogen and / or oxygen, we have made a complex carbonitride of Ti and W, a complex carbonate,
The object is achieved when it is a cemented carbide formed a cubic compound consisting of complex carbonitride oxide, and the sinterability is good, and there is little decrease in strength and toughness, and the knowledge that it can be manufactured at low cost, The present invention has been completed.

The cemented carbide tool member of the present invention contains 3 to 15% by weight of a binder phase containing Co as a main component, and is composed of a composite carbonitride, a composite carbonate, or a composite carbonitride of W and Ti. 3 to 30% by weight of the cubic compound consisting of one or more of the above, and the remainder being a polyhedral cemented carbide member comprising tungsten carbide and unavoidable impurities, and the polyhedral cemented carbide member is 3 to 30 from the surface of the hard alloy member to the inside
A surface layer consisting essentially of tungsten carbide and a binder phase is formed over a depth of μm, and the surface layer is evenly formed up to the cross section of the polyhedral cemented carbide member. A cemented carbide tool member, wherein the cemented carbide member contains 0.02 to 0.3% by weight of oxygen and / or nitrogen with respect to the entire cemented carbide member. To do.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Specifically, when the binder phase in the cemented carbide tool member of the present invention is, for example, only Co, 50% by weight or more of Co is the binder phase and the balance is N.
The case where it consists of one or more of i, Fe, Cr, V, Ti and W can be mentioned. Among them, especially for applications where importance is attached to corrosion resistance, W, Cr, N of 15% by weight or less is used.
A binder phase composed of a Co alloy in which i and V are solid-solved is preferable. When the content of the binder phase is less than 3% by weight based on the whole cemented carbide, the fracture resistance is deteriorated due to the decrease in toughness, and conversely 1
If the amount exceeds 5% by weight, the hardness decreases and the wear resistance and the plastic deformation resistance deteriorate. Therefore, the amount is set to 3 to 15% by weight.

The cubic compound in the cemented carbide tool member of the present invention is specifically, for example, (WTi) CN.
Composite carbonitride, (WTi) CO composite carbonate, (W
Ti) CNO complex carbonitride oxides and these
containing a and / or Nb, for example (WTiT
a) CN, (WTiNb) CN, (WTiTaNb) C
N composite carbonitride, (WTaTa) CO, (WTiN
b) CO, (WTiTaNb) CO composite carbonate,
(WTaTa) CNO, (WTiNb) CNO, (WT
The complex carbonitride oxide of iTaNb) CNO can be mentioned. The cubic compound may be a stoichiometric composition or a non-stoichiometric composition, and when Ta and / or Nb is contained, 1.
It is 0% by weight or less.

If the content of the cubic compound is less than 3% by weight based on the whole cemented carbide, the wear resistance and the plastic deformation resistance are deteriorated, and conversely, if it exceeds 30% by weight, the toughness is increased. Since the fracture resistance deteriorates due to the decrease, it is set to 3 to 30% by weight. When Ta and / or Nb is contained in this cubic compound, if it exceeds 1.0% by weight with respect to the entire cemented carbide member, it becomes difficult to form a surface layer described later. Preferably, the content of Ta and / or Nb in the cubic compound is 0.6% by weight or less based on the whole cemented carbide member.

Another tungsten carbide constituting the cemented carbide tool member preferably contains a plate-like crystal WC in order to improve strength, toughness, fracture resistance and chipping resistance. This plate crystal WC is specifically the aspect ratio of the WC crystal in the cross-sectional structure, in other words, the grain size of tungsten carbide in which the maximum length / minimum length of one crystal is 3 or more. Is. It is preferable that the plate-like crystal WC is contained in an amount of 30% by volume or more of the entire cemented carbide member, because hardness and toughness are improved and both wear resistance and fracture resistance are improved. If the aspect ratio of the plate-like crystals WC is less than 3 and the content ratio of the plate-like crystals WC is less than 30% by volume of the whole cemented carbide member, the effect of improving wear resistance and fracture resistance is small.

Specifically, the surface layer formed on the surface of the cemented carbide tool member does not substantially contain the above-mentioned cubic compound and is composed of tungsten carbide and a binder phase. is there. If the depth of this surface layer is less than 3 μm from the surface, the improvement in toughness is small and the effect of improving fracture resistance is low.
On the contrary, if the depth exceeds 30 μm, the plastic deformation resistance and the wear resistance are deteriorated, so that it is 3 to 3 from the surface of the cemented carbide member.
It is set to 0 μm. When used as the base material of the coated cemented carbide, it is preferably 10 to 20 μm.

The surface layer formed on the surface portion of this cemented carbide member has an average binder phase amount from the internal average binder phase amount located at a depth of 0.2 mm or more from the surface of the cemented carbide member. When the amount is 1.05 to 1.30 times, the toughness of the surface layer is increased and the fracture resistance is further improved, which is preferable. When the binder phase in the surface layer is non-uniformly distributed, for example,
It is also preferable that the surface of the cemented carbide member is as large as possible, has a maximum value in the central portion, and is distributed in a gradient composition component state.

The coated cemented carbide tool member of the present invention in which a coating is coated on the cemented carbide member as described above is a pre-cured portion having a width of 0.3 mm or less at the traverse portion of the cemented carbide member having the above-mentioned surface layer. It is preferable to coat the surface with a coating after the honing process. The pre-honing process is, for example, a straight line, a circular line, a straight line and a circular line of the traverse line part of the cemented carbide member made of a polyhedron by a grinding wheel, a brush, or the like.
It is used to process arcs and arcs. If the width of the pre-honing process becomes larger than 0.3 mm, the tendency of accommodating cutting resistance and deterioration of the finished surface becomes large. Therefore, the range is preferably 0.02 to 0.2 mm.

It is preferable that the surface layer on the ridge portion is present on the entire ridge portion, but it may be removed by the above-mentioned pre-honing process. In particular, when it is used as a cutting tool, it is preferable to leave the surface layer on the ridge portion forming the cutting edge because the effect of improving the fracture resistance of the coated cemented carbide tool member is great. Even if the surface layer in the cross line portion is processed and removed, the area ratio of the surface layer remaining on the ridge line portion near the other cutting edge is relatively large, so that the fracture resistance is improved as compared with the conventional product.

The coating of the coated cemented carbide is specifically TiC, Ti (CN), TiN, TiCO, Ti.
NO, TiCNO, (TiAl) N, (TiAl) C
N, (TiAl) NO, (TiAl) CNO, Al ₂ O ₃
Can be mentioned. These coatings are specifically
For example, TiN, TiCN, TiC, (TiAl) N,
(TiAl) CN, (TiAl) NO, (TiAl) C
On one kind of monolayer film in NO, or cemented carbide member, T
iC-Ti (CN) -TiN, TiN- (TiAl)
N, TiCN- (TiAl) N, TiN-Ti (CN)
It is also a preferable coating structure to form a multilayer film in which coating films of --TiC--Al ₂ O ₃ --TiN are sequentially coated. The total thickness of this coating is preferably 2 to 20 μm from the viewpoint of wear resistance and fracture resistance, and particularly preferably selected according to the application, for example, 8 to 15 μm for turning tools, and for milling tools. Is 3 to 6 μm.

[0018]

In the cemented carbide tool member having a tough ridge of the present invention, oxygen and / or nitrogen contained in the cemented carbide member acts to form a uniform surface layer up to the ridge. The surface layer that is evenly formed up to the part acts to improve fracture resistance and chipping resistance when used as a cutting tool. Further, in particular, a coated cemented carbide tool member in which a coating is coated after pre-honing the traverse portion has wear resistance due to the action of both the coating and the surface layer in addition to the action in the above-described cemented carbide tool member. The fracture resistance is remarkably improved without a decrease in

[0019]

Example 1 Commercially available WC having an average particle size of 3.5 μm, 1.0 μm (WTi) C composite carbide (WC / TiC = 70/30 by weight ratio), 1.2 μm TiN,
1.0 μm Co, 1.0 μm TaC, 2.2 μm W, 6 μm graphite (denoted as G in the table), 0.02 μm TiO ₂ , 1.5 μm ZrN, 1.1 μm ZrC,
2.0 μm of each HfN powder was weighed to the composition shown in Table 1, inserted into a stainless steel pot with an acetone solvent and a cemented carbide ball, mixed and pulverized for 48 hours, and then dried to obtain a mixed powder. Obtained.

Using this mixed powder, JIS-B412
0 with a die of CNMG120408 (with a breaker) described in No. 0 at a pressure of ² ton / cm ² , and the obtained powder compact is vacuum-pressed at an atmospheric pressure of 10 Pa.
Inventive products 1 to 5 and comparative products 1 to 5 were obtained by heating and sintering at 20 ° C. for 1 hour.

The cemented carbide members of the invention products 1 to 5 and comparative products 1 to 5 thus obtained were each cut, and the cut surfaces were subjected to polishing and lapping with a diamond paste of 1 μm, and then a scanning analysis electron microscope. Using a metallographic microscope, a Rockwell hardness tester, and an image processing device, composition analysis, structure observation, and measurement of mechanical property values were performed. The contents of the measurement were the observation of the surface layer of the alloy and the average composition within 0.5 mm from the surface, the thickness of the surface layer at the cross line portion and the flat portion (minimum depth from the surface), and burrows (CIS-006B / 1983). (Displayed as a standard), hardness within 0.5 mm from the surface (HRA), fracture toughness value (K _1c ) (load by IM method: 196 N), and content ratio of plate-like crystals WC by the image processing apparatus. The alloy composition results are shown in Table 2 and the others are shown in Table 3.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

Example 2 The traverse portions (cutting edges) of the products 1 and 2 of the present invention and the comparative products 1 and 2 obtained in Example 1 were subjected to R honing of 0.03 mm using a diamond brush. Work piece: SCM4 using 3 of the obtained cemented carbide tool tips
40, cutting speed: 100 m / min, depth of cut: 2.0 m
m, feed: a dry milling cutting test was performed under the condition of 0.25 mm / blade, the average life time until chipping or breakage of the cutting blade was obtained, and the results are shown in Table 4. The thickness of the surface layer after honing (minimum depth from the surface) is also shown in Table 4.

[0026]

[Table 4]

[0027]

Example 3 The traverse portions (cutting edges) of the products 2, 3 and 4 of the present invention and the comparative products 2, 3 and 4 obtained in Example 1 were subjected to R honing of 0.05 mm using a diamond brush. rear,
Using a CVD coating device, from the cemented carbide tool member side, 1.0 μm TiN, 6.0 μm TiCN, 1.
A total of 12 μm of 0 μm TiC, 3.0 μm Al ₂ O ₃ and 1.0 μm TiN was coated, and coated cemented carbide tool members of the present invention products 6, 7, 8 and comparative products 6, 7, 8 were respectively prepared. Obtained.

Using each of the coated cemented carbide tool members thus obtained, a work material: S48C (with four grooves),
A dry interrupted turning test was conducted under the conditions of cutting speed: 200 m / min, depth of cut: 2.0 mm, feed: 0.25 mm / rev, and chipping of the cutting edge, damage to the cutting edge, and average flank wear width were 0.30 mm. The average life time up to was determined and the results are shown in Table 5. The thickness of the surface layer after honing (minimum depth from the surface) is also shown in Table 5.

[0029]

[Table 5]

[0030]

EFFECTS OF THE INVENTION The cemented carbide tool member having a tough ridge line of the present invention has excellent sinterability as compared with a cemented carbide member having a similar structure in the related art, and has small variations in various characteristic values. Especially, when used as a milling cutting tool and an intermittent turning tool, the chipping resistance and chipping resistance are remarkably excellent, and there is an effect that the life is extended. Further, the coated cemented carbide tool member having a tough ridge line portion of the present invention has substantially the same effect as described above, as compared with the conventional coated cemented carbide member having substantially the same configuration.

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Claims (7)

[Claims] 1. A cubic crystal composed of a binder phase containing Co as a main component in an amount of 3 to 15% by weight and at least one selected from a complex carbonitride, a complex carbonate and a complex carbonitride of W and Ti. 3 compounds
-30% by weight, the balance being a polyhedral cemented carbide member composed of tungsten carbide and unavoidable impurities, and the polyhedral cemented carbide member is 3 to 3 inward from the surface of the cemented carbide member. A surface layer consisting essentially of tungsten carbide and the binder phase is formed over a depth of 30 μm, and the surface layer is evenly formed up to the traverse portion of the polyhedral cemented carbide member. Which is a cemented carbide tool member, wherein the cemented carbide member, with respect to the entire cemented carbide member,
A cemented carbide tool member having a tough ridge, characterized by containing 0.02 to 0.3% by weight of oxygen and / or nitrogen. 2. A binder phase containing Co as a main component in an amount of 3 to 15% by weight, and one of complex carbonitrides, complex carbonates and complex carbonitrides of W, Ti, Ta and / or Nb. 3 to 30% by weight of a cubic compound composed of at least one kind, and the remainder being a polyhedral cemented carbide member composed of tungsten carbide and inevitable impurities, and the polyhedral cemented carbide member is
3 to 30 μm from the surface of the cemented carbide member toward the inside
A surface layer consisting essentially of tungsten carbide and the binder phase is formed over the depth of, and the surface layer is evenly formed up to the cross section of the polyhedral cemented carbide member. A cemented carbide tool member, wherein the cemented carbide member contains 0.02 to 0.3% by weight of oxygen and / or nitrogen with respect to the entire cemented carbide member. A cemented carbide tool member having a tough ridge, wherein Ta and / or Nb contained in the system compound is 1.0% by weight or less based on the entire cemented carbide member. 3. The tungsten carbide contains a plate crystal WC having an aspect ratio of 3 or more in a cross-sectional structure,
The cemented carbide tool member having a tough ridge line portion according to claim 1 or 2, wherein the plate crystal WC is 30% by volume or more of the entire tungsten carbide contained in the cemented carbide member. 4. The surface layer has an average Co content of 1. of an internal average Co content at a depth of 0.2 mm or more from the surface.
05 to 1.30 times, and
Alternatively, a cemented carbide tool member having the tough ridge line part according to 3. 5. The cross-sectional portion, wherein the surface layer remains 10 μm or less, 1, 2, 3 or 4.
A cemented carbide tool member having the tough ridge portion described. 6. A carbide, nitride, carbonitride, carbonate, oxynitride, carbonitride of titanium on a cemented carbide tool member having a tough ridge line portion according to claim 1, 2, 3, 4 or 5. A toughness characterized by being coated with one single layer or two or more layers of oxides, titanium-aluminum nitrides, carbonitrides, nitrous oxides, oxycarbonitrides, and aluminum oxides. A coated cemented carbide tool member having a ridge. 7. The tough ridge line portion according to claim 6, wherein the coating film is formed after the ridge line portion of the cemented carbide member is subjected to pre-honing processing with a width of 0.3 mm or less. A coated cemented carbide tool member having.