JP3954845B2 - Tungsten carbide-based cemented carbide and method for producing the same - Google Patents

Tungsten carbide-based cemented carbide and method for producing the same Download PDF

Info

Publication number
JP3954845B2
JP3954845B2 JP2001396304A JP2001396304A JP3954845B2 JP 3954845 B2 JP3954845 B2 JP 3954845B2 JP 2001396304 A JP2001396304 A JP 2001396304A JP 2001396304 A JP2001396304 A JP 2001396304A JP 3954845 B2 JP3954845 B2 JP 3954845B2
Authority
JP
Japan
Prior art keywords
carbide
cemented carbide
phase
cr
ta
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2001396304A
Other languages
Japanese (ja)
Other versions
JP2003193172A (en
Inventor
裕 久保
Original Assignee
日立ツール株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日立ツール株式会社 filed Critical 日立ツール株式会社
Priority to JP2001396304A priority Critical patent/JP3954845B2/en
Publication of JP2003193172A publication Critical patent/JP2003193172A/en
Application granted granted Critical
Publication of JP3954845B2 publication Critical patent/JP3954845B2/en
Application status is Expired - Fee Related legal-status Critical
Anticipated expiration legal-status Critical

Links

Description

[0001]
[Technical field belonging to the invention]
The present invention relates to a cemented carbide, and particularly to a so-called ultrafine cemented carbide having tungsten carbide particles having an average particle size of 0.6 μm or less.
[0002]
[Prior art]
Ultrafine cemented carbide containing WC particles having an average particle size of 1 μm or less has high toughness as well as hardness, and is therefore widely used in end mills, printed circuit board drills, various shearing blades, and the like. In recent years, with the trend of fine processing and high-speed processing, the average particle size of ultrafine alloy is becoming increasingly smaller, and there is an increasing demand for high heat resistance and oxidation resistance. Since it is necessary to make the grain size of WC constituting the cemented carbide finer in order to adapt to the application of microfabrication, conventionally known metals such as V, Ta, Cr, or compounds of these metals (Carbides, nitrides, carbonitrides, etc.) have been used alone as grain growth inhibitors for WC, but two or more types have been added for an average particle size of 0.6 μm or less. . For example, Japanese Patent Publication No. 62-56224 (Patent No. 1539991) discloses a device that does not deteriorate toughness by adding two kinds of V and Cr and preventing the third phase from appearing in the alloy.
[0003]
Also, in Japanese Patent No. 3008532, the bending strength is improved by adding V and Cr in combination and allowing the composite carbide containing V and W to exist as a third phase at the metal boundary and the grain boundary of WC. It is disclosed that it can be achieved. Japanese Patent No. 3010859 is also a patent for composite addition of V and Cr, but Cr and V composite carbide without precipitating Cr carbide or (W, V) C, more accurately (Cr, V) It is disclosed that only 2 C is dispersed in the substrate to improve both hardness and toughness. Japanese Patent Publication No. 62-56493 (Patent No. 1467291) discloses the addition of three kinds of V, Cr and Mo. In Japanese Examined Patent Publication No. 62-56494 (Patent No. 1487479), three types of V, Cr, and 0.5 to 8.0% by weight of TaC or (Ta, Nb) C are added. It is disclosed that an alloy is obtained. In this case, if the precipitation phase of the solid solution carbide phase mainly composed of TaC or (Ta, Nb) C is not more than a certain amount, it is said that the toughness is not lowered. Japanese Patent Publication No. 03-46538 also discloses three types of addition of V, Cr, and 0.4 to 0.5% TaNbC. Japanese Patent No. 3206375 also discloses an ultrafine alloy having a WC grain size of 0.7 to 1.0 μm by the combined addition of V, Cr and 0.05 to 2.5% TaC. At present, no measures that are sufficiently effective are disclosed as measures for improving the heat resistance and oxidation resistance of so-called ultrafine cemented carbides having an average particle diameter of WC of 0.6 μm or less.
[0004]
[Problems to be solved by the invention]
As for the refinement of the WC particles, since the WC particles cause grain growth during sintering, the particle size of the WC particles in the alloy is larger than that before sintering. Therefore, research on a method for suppressing grain growth of WC by adding a grain growth inhibitor is advanced, and it is known that V is the most effective and Cr, Ta, and Mo are also effective. If the average grain size is 0.6 μm or less, and hopefully 0.5 μm or less, a large amount of grain growth inhibitor, especially V, may be added, but if a large amount of V is added, the toughness of the alloy decreases rapidly. To do. For this reason, attempts have been made to reduce the amount of addition of V and compensate for the resulting decrease in grain growth suppression effect with Cr or Ta, that is, combined addition of grain growth inhibitor. However, the inventors have intensively studied including the above prior art, and in the combination of V and Cr, a third phase separate from the binder phase and the WC phase precipitates during cooling after sintering, which is toughness. It became clear that it lowered. Therefore, if the addition amount is reduced to such an extent that the third phase does not precipitate, the effect of suppressing grain growth becomes dilute. The combination of V and Ta makes the appearance of the third phase easier, and the toughness is drastically reduced. Therefore, to obtain a tough cemented carbide having an average particle size of 0.6 μm or less and preferably 0.5 μm, it is necessary to rely on the addition of three types of V, Cr, and Ta. However, as a result of the above-described prior art being additionally tested, it has been found that the addition of Ta, like the combination of V and Ta, is a major obstacle to the reduction in toughness.
[0005]
Next, as for the oxidation resistance of the ultrafine cemented carbide, WC, Co and / or Ni, which are the main constituent elements, have no significant difference when the oxidation start temperature is around 600 ° C. However, the progress of oxidation is higher in WC, and it can be said that WC controls the oxidation of cemented carbide. However, WC lacks the property of incorporating other metal elements, and it is difficult to change the properties of WC. On the other hand, it is easier to change the properties of Co and / or Ni as the binder phase than WC. However, as described above, when various additives are used to obtain ultrafine cemented carbide, a new phase that appears to be a double carbide appears, which lowers the toughness of the alloy, but further improves oxidation resistance. In general, the addition of such an element results in a larger amount of new phases and a significant decrease in toughness. As for heat resistance, since WC originally has sufficient heat resistance, it is sufficient to consider making the metal bonded phase heat resistant. From the above considerations, both the oxidation resistance and heat resistance of the metal bonded phase are improved, and the appearance amount of a new phase other than WC and the metal bonded phase is not increased, or the toughness is not deteriorated. If the additive element can be found, a cemented carbide having a toughness, oxidation resistance, and heat resistance and an average particle diameter of WC of 0.6 μm or less can be obtained. In other words, the present condition is that the additive which has such a property is not known.
[0006]
[Means for Solving the Problems]
Therefore, the present inventors first conducted various studies on the toughness from the viewpoint of why the addition of three kinds of V, Cr and Ta can evaluate the grain growth suppressing effect, but causes a significant decrease in toughness. It was observed that other phases and obscurities that were clearly different from the WC phase spread throughout the alloy. This separate phase and obscured material (hereinafter referred to as the appearance phase) increases with the amount of Ta added, with the same amount of Ta, the lower the carbon alloy, the lower the cooling rate from the end of sintering to the liquid phase disappearance temperature. It was found that it decreased and disappeared in some cases. In addition, it has been clarified that the toughness, which is evaluated by the bending strength value, rapidly decreases as the amount of the appearance phase increases. That is, the present invention is one or two of Co and Ni: 2 to 30%, V: 0.1 to 2.0%, Cr: 0.1 to 2.0%, Ta: 0.01 % or more and less than 0.4%, Si: 0.1 to 1.5%, containing the remainder: in cemented carbide chromatic tungsten and unavoidable impurities carbide, a composition consisting of, the microstructure of the cemented carbide , Co, and / or a binder phase composed mainly of Ni, the average particle size of 0.6μm or less of tungsten carbide phase, Cr, Ta, 1 or two or more metal elements selected from V, Si and W the compound phase mainly composed of a tungsten carbide based cemented carbide, characterized in that it has three or more phase or 3-phase, further, the vacuum as a production method, a pressurized atmosphere or sintering sintering This is a production method in which the reaction is carried out in an atmosphere and / or a pressurized atmosphere and then rapidly cooled.
[0007]
Therefore, a rigorous investigation was conducted on the appropriate amount of Ta (in the case of Ta compound, Ta), and when it exceeded 0.4%, the appearance phase was excessive, and the V addition amount was in the range of 0.1 to 2.0. It became clear that sufficient toughness could not be maintained. Furthermore, how to adjust the amount of alloy carbon in the range where V is 0.1 to 2.0% and Cr is 0.1 to 2.0%, and also increase the cooling rate in the practical range. However, the desirable upper limit of the appearance phase is exceeded, and an alloy having a sufficiently tough WC average particle diameter of 0.6 μm or less cannot be obtained. Next, as for the oxidation resistance and heat resistance, the inventors have studied a wide range of substances and their amounts, and found that Si is suitable. Furthermore, the result that the addition effect of Si can be promoted when N was contained in the alloy was obtained. In addition, regarding the production method of the present invention, an alloy with higher toughness can be obtained when sintering is performed in a pressurized atmosphere, and further, the appearance phase is reduced by rapid cooling after pressure sintering, and the toughness is further improved. Results were also obtained. The effect of addition of Si can be expected even for a compound containing Si. In particular, tantalum silicide (Ta) powder, chromium silicide (Cr) powder, tungsten silicide (W) powder, and the like are convenient because Ta, Cr, and W are already contained in the alloy. For the addition of N, VN powder, TiN powder, Cr2N powder and the like are convenient for the same reason as described above.
[0008]
In the present invention, V (in the case of a V compound, V component) is 0.1 to 2.0%. If it is less than 0.1%, a sufficient grain growth suppressing effect cannot be obtained, which is contrary to the gist of the present invention. If it exceeds 0.2%, sufficient toughness cannot be obtained, and the bending strength is reduced to a practical range or less. Here, the practical range of the bending strength is set to 3000 MPa or more, but it may be used even less than that depending on the application, and is not strictly defined. Cr (in the case of a Cr compound, its Cr content) is 0.1 to 2.0%. If it is less than 0.1%, a sufficient grain growth suppressing effect cannot be obtained, which is contrary to the gist of the present invention. If it exceeds 0.2%, sufficient toughness cannot be obtained, and the bending strength is reduced to a practical range or less. Ta (in the case of a Ta compound, Ta content) is defined as 0.01% or more and less than 0.4%. If it is less than 0.01%, a sufficient synergistic effect for suppressing grain growth of V + Cr + Ta cannot be obtained, which is contrary to the gist of the present invention. If it is 0.4% or more, sufficient toughness cannot be obtained, and the bending strength is lowered to a practical range or less. Si (in the case of Si compound, Si content) is defined as 0.1 to 1.5%. If it is less than 0.1%, sufficient oxidation resistance and heat resistance cannot be obtained, which is contrary to the gist of the present invention. If it exceeds 1.5%, sufficient toughness cannot be obtained. Probably because the amount of the appearance phase becomes excessive. N (in the case of a compound, N content) is defined as 200 to 1000 ppm. If it is less than 200 ppm, sufficient oxidation resistance and heat resistance cannot be detected, and it is not enough to add N. If it exceeds 1000 ppm, the reason is currently unknown, but sufficient toughness cannot be obtained. Co and / or Ni is in the range of 2 to 30%. If it is less than 2%, sufficient toughness cannot be obtained. If it exceeds 30%, the decrease in hardness, which is one of the essential properties of cemented carbide, is remarkable, and it is not practical except for some applications.
[0009]
The microstructure of the cemented carbide of the present invention is basically two phases, a metal phase and a WC phase, but other phases may appear depending on the production conditions. Moreover, the appearance phase is observed depending on the condition in both cases. The appearing phase is mainly composed of one or more metals of Cr, Ta, V and Si and C, and Co and W are the constituent elements at other times. The appearance phase does not strictly define the chemical composition because the constituent elements and the composition ratio vary depending on the production conditions. When the present inventors diligently examined, when this appearance phase increases more than a certain amount, toughness will fall remarkably. Therefore, another feature of the present invention is that the amount of the appearance phase is limited by defining the amount of Ta. As a result, the average particle size of tough WC is 0.6 μm or less, preferably 0.5 μm or less. There is a place to obtain ultrafine alloy. Sintering may be carried out in a vacuum atmosphere, but if it is carried out in a pressurized atmosphere at atmospheric pressure or higher, the bending strength is improved. It is presumed that the sinterability is improved. After sintering in a pressurized atmosphere, bending strength is further improved by increasing the cooling rate by introducing a gas as a refrigerant into the furnace instead of furnace cooling. This is probably because the metal bonded phase was solid solution strengthened and basically the amount of the appearance phase that deteriorates toughness is reduced. Next, the present invention will be described in detail by examples.
[0010]
【Example】
As raw material powder, WC powder having an average particle size of 0.6 μm, Co, VC, Cr 3 C 2 , TaC, CrSi 2 each raw material powder of about 1 μm are blended so that the final composition shown in Table 1 is obtained, (VC, Cr 3 C 2 , TaC, and CrSi 2 are converted to V, Cr, Ta, and Si, respectively) After mixing for 12 hours in an alcohol-containing attritor containing a molding binder, granulate dry by spray drying did.
[0011]
[Table 1]
[0012]
The obtained granulated powder was press-molded at a pressure of 100 MPa to form a green compact, and the green compact was sintered in a vacuum atmosphere of 10 Pa to obtain a sintered body. A part of the sample was subjected to pressure sintering under a pressure of 3 MPa using Ar as a pressure medium after being kept at a high temperature under vacuum. Furthermore, a part of them was subjected to rapid cooling by evacuating Ar as a pressure medium once after pressure sintering and newly introducing low-temperature Ar gas. The sintering temperature and atmosphere are shown in Table 2, and the applied conditions are shown in Table 1.
[0013]
[Table 2]
[0014]
Next, each of these sintered bodies is ground to prepare a 4 mm × 8 mm × 24 mm JIS bending test piece, and the bending strength by bending at three points with a span of 20 mm is measured at room temperature in air and at 973 K in vacuum. Rockwell A scale hardness (HRA) was also measured. Further, after maintaining at 973 K for 1 hour in the air, the thickness of the generated oxide layer was measured to evaluate the oxidation resistance. Separately, the structure was observed with a scanning electron microscope (SEM) to determine the average particle diameter of WC. The fracture surface after measuring the bending strength at room temperature was subjected to element mapping with an X-ray microanalyzer (XMA) to investigate the presence or absence of an appearance phase. These results are shown together in Table 1.
[0015]
As for toughness, it can be seen from the Examples that the combined addition of V, Cr and Ta regulates the respective amounts, and the synergistic effect appears remarkably. In Comparative Example 1, since the Ta addition amount is 0, there is no synergistic effect of mixing three kinds, and the bending strength is as low as 3000 MPa or less. This is presumed to be due to the existence of a remarkable appearance phase with a characteristic of reducing toughness. In Invention Examples 2 to 5, the average particle diameter of WC is 0.6 μm or less, and a bending strength of 3000 MPa or more is maintained to be a high toughness alloy. In Comparative Example 6, since the amount of Ta exceeded 0.4%, the amount of the appearance phase increased, and the bending strength was less than 3000 MPa. In Comparative Example 7, since the Si addition amount is 0, the high temperature bending strength is 1000 MPa or less, the oxide thickness exceeds 50 μm, and the heat resistance and oxidation resistance are not improved. In Comparative Example 9, since the Si amount exceeds the suitable range of 0.1 to 1.5%, the bending strength at normal temperature is 3000 MPa or less and the toughness is low.
[0016]
In Invention Examples 10 to 12, Si and N are contained within the scope of the present invention, so that in addition to the normal temperature bending strength, the high temperature bending strength exceeds 1000 MPa, and the thickness of the oxide layer is 30 μm or less. It can be seen that the composition is excellent in resistance and oxidation resistance. In Comparative Example 13, the N content exceeds 1000 ppm and the toughness is insufficient. In Comparative Example 14, since the V addition amount is 0, the average particle diameter of WC is coarsened to 0.65 μm, and the grain suppressing effect is dilute. In Invention Examples 15 to 17, since the V amount is in the range of the present invention, that is, in the range of 0.1 to 2.0%, both the grain growth and the decrease in toughness are suppressed. It has become an alloy. In Comparative Example 18, since V is excessive, the bending strength is 3000 MPa or less and a rapid decrease in toughness is observed. In Comparative Example 19, since the amount of Cr added is 0, the effect of suppressing grain growth is dilute. In Comparative Example 21, although the Cr amount is excessive and there is a grain growth suppressing effect, the bending strength is 3000 MPa or less and low toughness. In Comparative Example 22, Co is insufficient and sufficient toughness is not obtained. In Comparative Example 25, Co is excessive and rigidity is insufficient, and sufficient bending strength is not obtained. Other examples of the present invention achieve an average particle size of WC of 0.6 μm and a minimum of 0.36 μm, and the bending strength is maintained at 3000 MPa. It can also be seen that the high temperature bending strength exceeds 1000 MPa, and the heat resistance is high. The thickness of the oxide layer produced by being held in a high-temperature atmosphere is thin and excellent in oxidation resistance. When quenched after sintering, no appearance phase occurs and high toughness is obtained.
[0017]
【The invention's effect】
From the above, the cemented carbide of the present invention has a very small WC particle size and high toughness, heat resistance and acid resistance, and is used for various cutting tools, shear tools, small diameter end mills, and printed circuit boards. Excellent performance when used in drills.

Claims (4)

  1. One or two of Co and Ni: 2 to 30%, V: 0.1 to 2.0%, Cr: 0.1 to 2.0%, Ta: 0.01% to 0.4% less, Si: 0.1 to 1.5%, containing the remainder: in cemented carbide chromatic tungsten and unavoidable impurities carbide, a composition consisting of, the microstructure of the cemented carbide, Co and / or Ni a binder phase composed mainly of, compound phase having an average particle diameter mainly the following tungsten carbide phase 0.6 .mu.m, Cr, Ta, V, one or more metal elements selected from Si and W And a tungsten carbide based cemented carbide characterized by having three or more phases.
  2. The tungsten carbide base cemented carbide according to claim 1 , wherein the cemented carbide has a nitrogen content in the range of 200 to 1000 ppm.
  3. 3. A method for producing a tungsten carbide-based cemented carbide according to claim 1, wherein the tungsten carbide-based cemented carbide is sintered in a pressurized atmosphere.
  4. In producing a tungsten carbide based cemented carbide according to claim 1 or 2, it was sintered in a vacuum atmosphere and / or pressurized atmosphere, a manufacturing method of the tungsten carbide based cemented carbide, characterized in that the subsequent rapid cooling.
JP2001396304A 2001-12-27 2001-12-27 Tungsten carbide-based cemented carbide and method for producing the same Expired - Fee Related JP3954845B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2001396304A JP3954845B2 (en) 2001-12-27 2001-12-27 Tungsten carbide-based cemented carbide and method for producing the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2001396304A JP3954845B2 (en) 2001-12-27 2001-12-27 Tungsten carbide-based cemented carbide and method for producing the same

Publications (2)

Publication Number Publication Date
JP2003193172A JP2003193172A (en) 2003-07-09
JP3954845B2 true JP3954845B2 (en) 2007-08-08

Family

ID=27602433

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2001396304A Expired - Fee Related JP3954845B2 (en) 2001-12-27 2001-12-27 Tungsten carbide-based cemented carbide and method for producing the same

Country Status (1)

Country Link
JP (1) JP3954845B2 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0816836D0 (en) 2008-09-15 2008-10-22 Element Six Holding Gmbh Steel wear part with hard facing
GB0816837D0 (en) 2008-09-15 2008-10-22 Element Six Holding Gmbh A Hard-Metal
US20120040183A1 (en) 2010-08-11 2012-02-16 Kennametal, Inc. Cemented Carbide Compositions Having Cobalt-Silicon Alloy Binder
JP6230156B2 (en) * 2014-09-22 2017-11-15 株式会社日本製鋼所 Lining material and cylinder for molding machine having the same

Also Published As

Publication number Publication date
JP2003193172A (en) 2003-07-09

Similar Documents

Publication Publication Date Title
KR100996838B1 (en) Super hard alloy and cutting tool
US20090074604A1 (en) Ultra-hard composite material and method for manufacturing the same
US6228139B1 (en) Fine-grained WC-Co cemented carbide
EP0392519A2 (en) Surface-coated tool member of tungsten carbide based cemented carbide
EP0259192B1 (en) A high toughness cermet and a process for the production of the same
DE102007046380B4 (en) Cutting tool
CN101466858B (en) Cemented carbide with refined structure
EP0062311A1 (en) Tungsten carbide-base hard alloy for hot-working apparatus members
EP0499223B1 (en) High toughness cermet and process for preparing the same
JPH0711048B2 (en) High strength nitrogen-containing cermet, and a manufacturing method thereof
CN101418394A (en) Superhard composite material and method for preparation thereof
EP0819776B1 (en) Cutting blade made of titanium carbonitride-type cermet, and cutting blade made of coated cermet
US4885132A (en) Cemented carbonitride alloy with improved plastic deformation resistance
CN100460546C (en) Cemented carbides
US5993506A (en) Plate-crystalline tungsten carbide-containing hard alloy, composition for forming plate-crystalline tungsten carbide and process for preparing said hard alloy
KR100973626B1 (en) Cermet insert and cutting tool
EP0635580A1 (en) Nitrogen-containing hard sintered alloy
JP4690475B2 (en) Cermet and coated cermet tools
US5421852A (en) Hard alloy and its manufacturing method
EP0759480A1 (en) Plate-crystalline tungsten carbide-containing hard alloy, composition for forming plate-crystalline tungsten carbide and process for preparing said hard alloy
DE10244955B4 (en) Cemented carbide, use of a cemented carbide and method of making a cemented carbide
EP2036997A1 (en) Coated cemented carbide cutting tool inserts
JP4870344B2 (en) Method for producing sintered carbide
EP0918097B1 (en) Hard sintered alloy
EP1359130B1 (en) Cubic boron nitride sintered body and cutting tool

Legal Events

Date Code Title Description
A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20060712

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20060907

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20070424

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20070427

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313531

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100511

Year of fee payment: 3

R360 Written notification for declining of transfer of rights

Free format text: JAPANESE INTERMEDIATE CODE: R360

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100511

Year of fee payment: 3

R370 Written measure of declining of transfer procedure

Free format text: JAPANESE INTERMEDIATE CODE: R370

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100511

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100511

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110511

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120511

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130511

Year of fee payment: 6

LAPS Cancellation because of no payment of annual fees