KR20100018997A - Alloy stuff and manufacturing process thereof for cutting tool - Google Patents

Abstract

PURPOSE: Sintered material for a cutting tool and a manufacturing method thereof are provided to improve abrasion resistance, plastic deformation resistance, oxidation resistance, and shock resistance. CONSTITUTION: A manufacturing method of sintered material for a cutting tool comprises the following steps of: combining two or more raw materials among metal carbide powder, metal-nitride powder, metal carbon nitride powder, Ni-A1 alloy power and W powder; forming powder compact by evenly mixing the material powder and press-molding the mixture; sintering powder compact at high temperature of 2000-2700°C under non-oxide atmosphere; and performing compound extraction process under non-oxide atmosphere.

Description

Sintering material for cutting tools with excellent high temperature characteristics and manufacturing method thereof

The present invention relates to a sintered material which has excellent high temperature characteristics, and particularly exhibits excellent cutting performance when used as a ball of a crusher, and a manufacturing method thereof.

In general, when cutting speed is increased or cutting amount is increased in cutting of steel materials, the cutting edge temperature of the cutting tool rises sharply rather than the cutting edge of the cutting tool is worn by the cutting resistance. In many cases, plastic deformation occurs and the service life is reached, and this tendency is gradually increased by high speed cutting and high efficiency cutting.

Accordingly, currently used cutting tools are cemented carbides or cermets in which the dispersed phase is mainly composed of W carbide or Ti carbide, while the bonded phase is mainly composed of steel-based metal. As it softens rapidly, not only these cemented carbides and cermets but also surface coated cemented carbides and surface coated cermets having hard coating layers formed on these surfaces, the conditions of use thereof are limited such that the blade edge temperature is slightly higher than 1000 ° C. The effect of high temperature cutting temperature on the wear resistance of the tool is very large.

On the other hand, ceramics containing A1 oxide as a main component have high hardness and excellent oxidation resistance at high temperatures, and are used as a ball crusher batter, but at the end of the day, it is found that the impact resistance is insufficient and the reliability is insufficient. In high speed cutting, the amount of feed is limited.

In addition, in recent years, as a cutting tool material for high speed cutting or high speed cutting, a main alloy having a structure in which W and Ti carbides are dispersed in a layer in a matrix made of a high melting point metal such as W or Mo (for example, US patent) Although the main alloy has a very high melting point of 2700 ° C. and a main alloy, it is difficult to give a complicated shape and insufficient oxidation resistance and impact resistance, and thus it is not widely used.

The present invention has been proposed in view of the above, and can provide a cutting tool material having excellent high temperature characteristics capable of continuous high-speed cutting and high-speed cutting, that is, cutting tool excellent in wear resistance, plastic deformation resistance, oxidation resistance and impact resistance. It is an object of the present invention to provide a sintered material and a method of manufacturing the same.

In order to achieve the above object, the sintering material for cutting tools having excellent high temperature characteristics of the present invention is Ti: 5-25%; One or two selected from Zr and Hf: 5-20%; One selected from Nb and Ta: 5-20%; Ni: 0.5-3.0%; A1: 0.5-2.0%; C: 15-40%; N: 1-15%; And W: 20-55% (more than atomic%).

In the method for producing a sintered material having excellent high temperature characteristics according to the present invention, a metal carbide powder, a metal nitride powder, a metal carbonitride powder, a Ni-A1 alloy powder, and a W powder are prepared as raw material powders. Blending more than one species; Mixing the blended raw material powder evenly and then press molding to form a green compact; Sintering the green compact so as to completely solidify at a high temperature of 2000-2700 ° C. under a non-oxidizing atmosphere; Performing a compound precipitation treatment at 1000-1600 ° C. under a non-oxidizing atmosphere after sintering; The disperse phase becomes a fine hard phase with the compound phase mainly containing Ti, C, and N, and the one or two of Zr and Hf, and the compound phase mainly containing C and N, and the binding phase is It is characterized by producing a sintered material having a texture of Ni-A1 intermetallic compound and W-based alloy mainly composed of W.

According to the present invention as described above, the cutting edge of the cutting tool is damaged by high temperature because the high temperature characteristic is greatly improved even in continuous high speed cutting and cutting with large cutting amount due to excellent wear resistance, plastic deformation resistance, oxidation resistance and impact resistance. There is no work, which greatly increases the service life of the tool. In particular, it is very useful in the case of premature burnout of the cutting edge due to the high temperature caused by the high cutting resistance such as the cutting tool tip of the road crusher.

The present invention has been made on the basis of the above facts, and the reason for limiting the component composition range and sintering temperature of the following materials as described above will be explained.

(a) Ti

    The Ti component has the effect of forming a compound phase composed mainly of Ti and C and N dispersed in a fine hard phase in the base material to impart high hardness to the material and improving wear resistance, but when the content is less than 5%, the sintering is performed. Precipitation of the compound in the cooling process from the solid solution state in the process, the desired amount of the compound can not be precipitated, as a result of the expected wear resistance can not be secured, while containing more than 25% relatively bonded Since the compound phase forming the dispersed phase becomes excessive compared to the phase and the impact resistance of the material is deteriorated, the content thereof is 5-25% (hereinafter, the content of all components is to use atomic% without using weight%. It is preferable to make ().

(a) Zr and Hf

    This component also has the effect of improving the wear resistance of the material by forming a compound phase containing, as Ti, one or two selected from Zr and Hf, and C and N as a main component, and dispersing as a fine hard phase in the base. If the content is less than 5%, similarly to Ti, high hardness, that is, high abrasion resistance cannot be secured. On the other hand, if the content is more than 20%, the compound phase forming the dispersed phase is excessively excessive, and the impact resistance of the material is worsened. It is preferable to set it as -20%.

(c) Nb and Ta

   These two components diffuse to the above two kinds of compounds, and have a function to enhance the oxidation resistance of the material by solid solution. However, if the content is less than 5%, the desired effect of the action cannot be obtained. When it contains more than%, the wear resistance of the material tends to be deteriorated, so the content thereof is preferably set to 5-29%.

(d) Ni and A1

Both of these components improve the sinterability of W constituting the bonded phase, form an intermetallic compound of Ni ₃ Al, and improve the bonding strength between the compound phase constituting the dispersed phase and the bonded phase, Although there is an effect of remarkably improving the impact property, if the content is less than Ni: 0.5% and A1: less than 0.5%, the desired effect can not be obtained according to the above action, while if it contains more than Ni: 3.0% and A1: 2.0% As the wear resistance of the material is lowered, the content of Ni is preferably 0.5-3.0% and A1: 0.5-2.0%, and when Al and Ni are simultaneously contained, Al / Ni is limited to 0.25-0.5. It is desirable to.

(e) C

    The C component has the effect of improving the wear resistance of the material by forming two kinds of compound phases as described above, but when the content is less than 15%, the amount of the hard dispersed phase is relatively small and the desired wear resistance cannot be secured. On the other hand, if the content is more than 40%, the ratio of the compound phase to the binding phase is excessive and the impact resistance of the material is deteriorated. Therefore, the content thereof is preferably set to 15-40%.

(f) N

    The N component has a function of further minimizing the compound phase to improve the impact resistance of the material, but if the content is less than 1%, the desired impact resistance cannot be secured. Since the amount of decomposition increases, bubbles are formed in the material, and as a result, the impact resistance deteriorates, so the content thereof is preferably 1-15%.

(g) W

    The W component partially diffuses in the above-described compound phase, but most of the remainder constitutes a desired binding phase, and the binding phase is composed of a component constituting the dispersed phase and a W-based alloy in which Ni and Al are dissolved. Has excellent plastic deformation resistance and impact resistance.

    However, if the content is less than 20%, the amount of the above-mentioned bound phase is relatively small, and in particular, the impact resistance deteriorates. On the other hand, if the content exceeds 55%, the disperse phase is relatively small and the wear resistance of the material is lowered. It is preferable to make the content into 20-55%. Further, the sintered material of the present invention may contain one or two or more of Fe, Co, Cr, Mo, Si, and platinum group metals (Pt, Pd, Rh, Ru, Ir, Os) as unavoidable impurities. If the total content is 2% or less, the characteristics of this sintered material will not be impaired at all, and the amount of inclusion of unavoidable impurities shall occupy a part of the W component.

(h) Sintering temperature

    At a sintering temperature of less than 2000 ° C., the structure during sintering does not become a completely solid solution. As a result, in the compound precipitation process after sintering, a structure in which fine hard compounds are uniformly dispersed in the base of the W-based alloy cannot be obtained. It is not possible to ensure wear resistance and impact resistance, and on the other hand, when the sintering temperature exceeds 2700 ° C, the liquid phase will appear, making it difficult to maintain the shape, it is preferable to set the sintering temperature to 2000-2700 ° C.

(i) compound precipitation treatment temperature

    If the temperature is less than 1000 DEG C, the amount of the compound that decomposes and precipitates is too small to obtain a structure in which the fine hard compound is uniformly dispersed. As a result, the wear resistance and the impact resistance of the material deteriorate, while the temperature exceeds 1600 DEG C. In the same manner, since decomposition and precipitation of a desired amount of the compound and the intermetallic compound cannot be performed, the compound precipitation treatment temperature is preferably 1100-1500 占 폚.

In addition, the sintering material for cutting tools of the present invention can be used alone, but one of Ni and A1 as a binding phase forming component: 25-50%, and one of Mo and W: 5-18%. A cermet gas phase having a composition consisting of one or two or more of carbides and nitrides of the metals of Groups 4a, 5a, and 6a of the periodic table as the hard-dispersed phase-forming component and an unavoidable impurity (more than atomic%) In this state, for example, the mixture may be held at a temperature of 1270 ° C. for 30 minutes in a vacuum atmosphere of 10 ⁻² torr, for example, to be used as a composite material, and in this case, the impact resistance is further increased.

In addition, carbides, nitrides and oxides of metals 4a, 5a and 6a of the periodic table, and two or more solid solutions thereof, aluminum oxide (hereinafter referred to as A1) are used on the surface of the sintered material of the present invention or the composite material by chemical vapor deposition. ₂ O ₃ ), zirconium oxide (hereinafter referred to as ZrO ₂ ), or a single layer or two or more layers of hard coat layer coated with an average layer thickness of 0.5-1.5 μm. It exhibits oxidation resistance.

     Next, the sintered material of this invention and its manufacturing method are demonstrated concretely by an Example.

Example 1

As raw material powder, 15.1 atomic% of Ti powder having an average particle size of 1.0 μm, 9.8 atomic% of Zr powder of 1.2 μm, 15.1 atomic% of Ta powder of 1.2 μm, 24.0 atomic% of C powder of 1.2 μm, 4.5 atomic% of N powder of 1.5 μm, 1.5 atom% of 1.7 μm Ni powder, 0.5 atom% of Al powder of 1.7 μm, and W powder of 1.2 μm were prepared in the remaining amount, and these raw material powders were blended in the above ratio, and wet-mixed by a ball mill for 72 hours and dried. , Press molding at a pressure of 15Kg / mm ₂ to form a green compact, which was maintained at 800 ° C. for 1 hour in H2 stream, and after presintering, 1 2600 ° C. in a vacuum atmosphere of 10 ^-1 torr. After the sintering was completed, the sintering was completed, the sintering temperature was cooled to 700 ° C./hr from the sintering temperature at 700 ° C./hr, and the compound precipitation treatment was performed at 1500 ° C. for 3 hours to perform the compound precipitation treatment. Eggplant produced the sintered material 1 of the present invention.

Example 2

Example 2 was tested under the same conditions as in Example 1, except that only some components and contents were different.

The composition components and the component contents used in this Example were 18.9 atomic% of Ti powder having an average particle size of 1.0 μm, 6.8 atomic% of Hf powder of 1.2 μm, 8.8 atomic% of 1.2 μm of Nb powder, and 27.5 C powder of 1.2 μm. Atom%, 1.5 atom N powder 4.0 atom%, 1.7 μm Ni powder 2.0 atom%, 1.7 μm Al powder 1.0 atom%, and 1.2 μm W powder were mixed in the remaining amount by the same method as in Example 1 Sintered material 2 was prepared and tested. The results are shown in Table 1.

Example 3

Example 3 was tested under the same conditions as in Example 1, except that only some composition components and contents were different.

The composition components and the component contents used in the examples were raw material powders of 23.3 atomic% of Ti powder having an average particle size of 1.0 μm, 5.0 atomic% of Hf powder of 1.2 μm, 6.1 atomic% of Nb powder of 1.2 μm, and C powder of 1.2 μm. Atom%, 1.5 atom N powder 4.1 atom%, 1.7 μm Ni powder 3.0 atom%, 1.7 μm Al powder 1.0 atom%, and 1.2 μm W powder were mixed in the remaining amount by the same method as in Example 1 Sintered material 3 was prepared and tested. The results are shown in Table 1.

Example 4

Example 4 was tested under the same conditions as in Example 1, except that only some components and contents were different.

The composition components and the component contents used in this example were 17.5 atomic% of Ti powder having an average particle size of 1.0 μm, 7.5 atomic% of Zr powder of 1.2 μm, 5.2 atomic% of 1.2 μm of Ta powder, and 3 μm of C powder 37.0. Atom%, 1.5 μm N powder 4.3 atom%, 1.7 μm Ni powder 4.5 atom%, 1.7 μm Al powder 0.5 atom%, and 1.2 μm W powder were mixed in the remaining amount by the same method as in Example 1 Sintered material 4 was prepared and tested. The results are shown in Table 1.

Example 5

Example 5 was tested under the same conditions as in Example 1, except that only some components and contents were different.

The composition components and the component contents used in this example were 14.5 atomic% of Ti powder having an average particle size of 1.0 μm, 9.5 atomic% of Zr powder of 1.2 μm, 7.0 atomic% of Hf powder of 1.2 μm, and 8.5 atom of Nb powder of 1.2 μm. %, 1.2 micrometers C powder 21.4 atomic%, 1.5 micrometers N powder 5.6 atomic%, 1.7 micrometers Ni powder 3.0 atomic%, 1.7 micrometers Al powder 1.0 atomic%, and 1.2 micrometers W powder were mixed in the remaining amount. Sintered material 5 was manufactured and tested in the same manner as in Example 1. The results are shown in Table 1. Where Zr and Hf are mutually substitutes, the minimum sum of both components should be 5 atomic% or more, and the maximum sum should not exceed 20 atomic%.

Example 6

Example 6 was tested under the same conditions as in Example 1, except that only some components and contents were different.

The composition components and the component contents used in this example were 15.8 atomic% of Ti powder having an average particle size of 1.0 μm, 6.3 atomic% of Zr powder of 1.2 μm, 18.4 atomic% of 1.2 μm of Ta powder, and 20.0 atomic C powder of 1.2 μm. %, 1.5 micrometers N powder 10.2 atomic%, 1.7 micrometers Ni powder 2.0 atomic%, 1.7 micrometers Al powder 1.0 atomic%, and 1.2 micrometers W powder were mixed by the remaining amount, Bill 6 was prepared and tested. The results are shown in Table 1.

Comparative Example 1-Comparative Example 7

 Comparative sintered material 1-7, which is used as a comparison example with the examples, has a composition in which any component content is out of the scope of the present invention, and their composition components and component contents are as shown in Table 1, and It is indicated by an * mark next to the component content to indicate that the component is out of range in 1.

[Analysis]

Next, a cutting tip having the shape of SNP432 was produced from each of the sintering materials 1-6 and the comparative small alloys 1-7 of the present invention obtained as a result, and the workpiece: JIS, SNCM-8 (hardness H _B 260), cutting speed : 230m / min, Feeding speed: 0.4mm / rev, Cutting depth: 2mm, Cutting time 10 minutes each for continuous cutting test and workpiece: JIS.SNCM-8 (Hardness H _B 280), Cutting speed: 140m / min Intermittent high speed cutting test was performed under the conditions of feed speed: 0.275mm, cutting depth: 2mm, cutting time 3 minutes. In the continuous high speed cutting test, the depth of flank wear and crete wear on the tip edge were measured. In the intermittent high speed cutting test, the number of missing defects in the ten test cutting edges was measured.

These measurement results are shown in Table 1.

Table 1 also shows Ti carbide (TiC) and A1 oxide (A1 ₂ O ₃ ) by chemical vapor deposition on the surfaces of ceramic cutting tips mainly composed of A1 oxide and cemented carbide based on W carbide for comparison purposes. The surface coating cemented carbide cutting tips (formerly known as cutting tips 1 and 2) coated with a total average layer thickness of 占 퐉 were shown together with the results of the cutting test under the same conditions. As is apparent from Table 1, the conventional cutting tip 1 was found to have a particularly low impact resistance, so that all of the cutting edges of the test cutting tip were missing, and the conventional cutting tip 2 had excellent impact resistance. It showed excellent cutting performance equivalent to that of sintered material, but showed a high wear resistance in continuous high speed cutting test due to its low wear resistance.

On the other hand, the sintered material 1-6 according to the embodiments of the present invention showed a significantly lower damage ratio than the comparative examples and the conventional cutting tips in the intermittent high speed cutting test, and the high speed cutting in which the continuous cutting operation is performed. Frank wear in the test was excellent in the wear characteristics of only about 1/2 to 1/3 compared to the comparative example and the conventional example, and in the comparison of the crater wear, it is difficult to measure at all due to a defect in the comparative example. In some cases, as compared to 35 to 55mm in most cases, in the embodiments of the present invention showed a relatively low wear characteristics of about 25 to 30mm. In addition, in the case of the conventional ceramic cutting tips, the wear measurement itself was not significant at all, and in the case of the surface-coated cemented carbide, the wear was severe enough that the cracker wear reached 150 mm. It was confirmed that a tool suitable for high speed cutting accompanied by generation can be provided.

It can be seen from the low cutting performance results shown in the intermittent and continuous high-speed cutting tests of Comparative Examples 1-7 that are similarly composed of the embodiments of the present invention and the compositional components. If you deviate a lot, you will see a decrease in cutting performance.

                           Table 1

Claims (2)

Ti: 5-25%; One or two selected from Zr and Hf: 5-20%; One selected from Nb and Ta: 5-20%; Ni: 0.5-3.0%; A1: 0.5-2.0%; C: 15-40%; N: 1-15%; And W: sintered material for cutting tools having excellent high temperature characteristics, characterized in that it is composed of 20-55% (more than atomic%). Preparing a metal carbide powder, a metal nitride powder, a metal carbonitride powder, a Ni-A1 alloy powder, and a W powder as a raw material powder, and blending two or more of these powders; Mixing the blended raw material powder evenly and then press molding to form a green compact; Sintering the green compact so as to completely solidify at a high temperature of 2000-2700 ° C. under a non-oxidizing atmosphere; Performing a compound precipitation treatment at 1000-1600 ° C. under a non-oxidizing atmosphere after sintering; The disperse phase becomes a fine hard phase with the compound phase mainly containing Ti, C, and N, and the one or two of Zr and Hf, and the compound phase mainly containing C and N, and the binding phase is A method for producing a sintered material for cutting tools having excellent high temperature characteristics, characterized by producing a sintered material having a texture of Ni-A1 intermetallic compound and W-based alloy containing W as a main component.