JPH0892607A - Production of composite hard material - Google Patents

Abstract

PURPOSE: To provide a method for producing a composite hard material capable of obtaining an axisymmetric long-sized composite hard material with a simple process without need for a new device or special modification by using a press- extruder and a vacuum sintering furnace. CONSTITUTION: Plural kinds of materials are optionally selected from the sintered hard alloys with WC as the hard grain and an iron-family metal as the main binder phase and the cermet alloys with TiC or Ti(C,N) as the hard grain and an iron-family metal as the main binder phase to produce a multilayer composite high-humidity material. In this case, the multilayer material is placed into a cylinder, pushed by a piston and extruded from the cylinder, and a composite hard material having an optional section is formed. The interfaces are joined by the diffusion of the main binder phase in the succeeding sintering stage. A long-sized multilayer composite hard material is obtained in this way with a simple process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a drill, an end mill,
In fields such as punches and dies where cemented carbide and cermet alloys have been conventionally used, higher strength, toughness,
The present invention relates to a method of manufacturing a hard material having a composite structure, which can obtain a material having wear resistance.

[0002]

2. Description of the Related Art There have been high demands for laminated tool materials, and many inventions and ideas have been made regarding laminated tool materials. Some examples of these are Japanese Patent Publication No.
6882, JP-A-55-31563, JP-A-56-
There are inventions disclosed in Japanese Patent Laid-Open No. 93877, Japanese Patent Laid-Open No. 4-319435, and the like. These are related to planar stacking such as a throw-away tip tool, and are useful inventions for products for which sufficient performance can be obtained. However, the fields of application of hard materials are not limited to such shapes, and there are many shaft cutting tools such as drills and end mills, and axisymmetric wear resistant tools such as punches and dies. Examples of inventions relating to an axisymmetric composite structure hard material include JP-A-61-144229 and JP-A-3-9053.
3, JP-A-3-90534, JP-A-3-21124.
There are disclosure examples in each gazette of No. 9, etc.

Of these, the invention relating to the manufacturing method is disclosed in JP-A-61-144229. The present invention comprises the steps shown in FIG. That is, according to the present invention, the core member 22 and the outer member 23 are combined to form the rod-shaped member 24.
And a composite process step 27 for extruding the composite process from the cemented carbide die 26 into a composite alloy 24A by hot hydrostatic extrusion, and a hot isostatic process for charging the composite alloy into the furnace 29. Pressure processing step 28, and further plastic processing step 3
0, an outer shape processing step 31, and a heat treatment processing step 32 (quenching and quenching step 32A, tempering step 32B), an axisymmetric composite structure hard material is manufactured.
Further, JP-A-3-90533 and JP-A-3-90534.
The invention disclosed in each of the publications relates to a material structure, but the manufacturing method shown as an example thereof is such that after the powder is filled by a press, the powder is filled into an axially symmetric multilayer. It is to apply pressure.

Further, the invention disclosed in Japanese Patent Laid-Open No. 3-211249 also relates to a material structure, but the manufacturing method shown in the embodiment is applied to a green compact or a sintered body after molding. , A heating process in a decompressed decarburizing atmosphere, a temperature holding process in a depressurized weak carburizing atmosphere, and a heat treatment process of cooling in a mixed gas atmosphere of a pressurized inert gas and a carburizing gas, A symmetric composite structural hard material is obtained.

[0005]

Each of the above inventions has many problems. For example, according to the method disclosed in Japanese Patent Laid-Open No. 61-144229, it is possible to manufacture a composite material by combining various materials, but a hot composite alloy working step, a hot isostatic pressing step, and a plastic working step. It is necessary to go through various processes such as heat treatment process. It goes without saying that going through these complicated steps requires a great deal of cost, and in some cases, the quality of the material may deteriorate due to cooling and heating in each step.

Further, in the case of the inventions disclosed in JP-A-3-90533 and JP-A-3-90534, a powder molding press is used. The powder molding press is optimal for mass-production of small items such as throw-away chips, but it is difficult to transmit pressure in the filling depth direction, so it is difficult to mold long products. difficult. In the case of a cylindrical shape, the length is limited to 2 to 3 times the diameter, and it is impossible to make a drill or an end mill. Even if molding could be done, there is an internal difference in the density of the formed body due to the difference in the applied pressure in the vicinity of the upper and lower punches and the part far from this, and the product after shrinking due to sintering , The diameter of the central part is deformed into a thin, hourglass-like shape compared to both ends. Therefore, it takes a great deal of time to uniformly grind the outer peripheral portion, and further, a situation may occur in which all the outer layers at the corners are scraped off.

Further, in order to carry out the invention disclosed in Japanese Examined Patent Publication No. 3-211249, gas pipes in a decarburizing atmosphere or a carburizing atmosphere, safety measures, etc. are originally unsuitable for the production of cemented carbide and cermet. New equipment and processes must be added. The present invention has been made to solve the above problems, using a press extruder and a vacuum sintering furnace, which have been widely used for the production of cemented carbide and cermet, to newly install or specially modify the apparatus. It is an object of the present invention to provide a method for producing a hard material having a composite structure which enables a long hard material having a composite structure to be obtained by a simple process that does not require.

[0008]

In order to solve the above problems, the present invention provides a cemented carbide containing WC as a hard particle and an iron group metal as a main bonding phase, and TiC or Ti (C, N) as a hard particle. Among the cermet alloys having the iron group metal as the main bonding phase, in the method for producing a composite structure hard material that forms a multilayer structure by selecting any plurality of material types, the raw materials that form the multilayer structure are charged into the cylinder, and Is extruded from the cylinder by pushing with a piston to form a composite structural hard material having an arbitrary cross section, and a step of joining the interfaces by diffusion of the main binder phase in the subsequent sintering step.

[0009]

EXAMPLES First, the molding process will be described. The raw material powder is previously provided with a molding binder in an amount according to the required specifications of the molded body. Taking the case of mixing paraffin with general cemented carbide as an example, when the paraffin content is less than 2.5 wt%, the raw material remains powdery. It may be spherically granulated if necessary. Paraffin is 2.5 ~
When the content is 5.0 wt%, the raw material becomes lumpy. Furthermore, when the amount of paraffin is increased, the raw material changes from rice cake-like to gel-like. When charging the raw material into the cylinder, an appropriate material is selected from these properties to form a multilayer structure as shown in FIG. For example, a powdery material is preformed by a press into a pipe shape, then charged into the cylinder 1 to form the outer layer 4, and the inner layer 5 is filled with a powdery material or a gel material.
Alternatively, the dough-like raw material may be formed into a rod shape by a deaeration type screw extruder to stand in the center of the cylinder to form the inner layer 5, and the outer layer 4 may be formed by filling the spherically granulated raw material around it. .

The raw material having a multi-layer structure formed in the cylinder 1 is extruded by the piston 2 into a predetermined long product. By changing the shape of the nozzle 3 attached to the cylinder outlet, it is possible to change the outer shape and laminated state of the molded product. The formed material is heated and degreased in a degreasing furnace. At this time, hydrogen gas for facilitating degreasing, nitrogen gas / argon gas for preventing alteration, etc. can be used. Degreasing is completed at about 500 ° C or lower, but if it is necessary to enable machining before sintering, 80
You may heat to 0 degreeC-900 degreeC.

In sintering, 1300 ° C to 1500 ° C
At the temperature of, the material with the predetermined cross section and the predetermined shape is made dense. Sintering of cemented carbide and cermet involves heating a material to a liquid phase appearance temperature such as cobalt and nickel, which are main binding phases, and densifying hard particles by the surface tension of the liquid. Therefore, even in the case of materials having a laminated cross-sectional shape, by heating above the liquid phase appearance temperature of all the constituent materials, the respective main binding phases diffuse in the liquid phase state and a uniform and strong joint surface is formed. Further, since cobalt and nickel are solid-solved in all proportions, there is no limitation on the amount of the main bonding phase of the material constituting the laminated material or the combination thereof. By adjusting the heating time, the gradient of the concentration change of the binder phase can be controlled,
The internal stress after cooling caused by the difference in the amount of binder phase can be set within an appropriate range.

The results of trial manufacture of a composite structure hard material will be described below. (Example 1) A cemented carbide powder having 12.0 wt% Co and the balance WC was mixed with 7.0 wt% paraffin and kneaded for 1 hour to form a dough. It was formed into a pipe shape having 45 mm, an inner diameter of 22 mm, and a length of 250 mm. 22m after charging this into the cylinder
In the hole of m, Co 6.0 wt%, TiC 1.0 wt%,
A lump-shaped material in which 5.0 wt% of paraffin is mixed in the remaining WC cemented carbide powder is press-fitted. After that, 4 with a piston
A pressure of 0 kg / cm ² was applied to extrude a rod having an outer diameter of 3.4 mm. Subsequently, while maintaining the inside of the furnace at 10 ^-1 to 10 ^-3 torr, it is heated to 450 ° C at a rate of 25 ° C / hour to degrease paraffin, and then heated at a rate of 10 ° C / minute.
Hold at 20 ° C. for 1 hour.

The sintered material was rod-shaped with an outer diameter of 2.7 mm, outer Co 12.0 wt%, the remaining WC cemented carbide layer had a thickness of 0.8 mm, inner Co 6.0 wt%, and T.
The diameter of the cemented carbide portion of iC 1.0 wt% and the balance WC was 1.1 mm. This material was ground to produce the drill for drilling the printed circuit board shown in FIG. By using a tough material for the outer layer 6 and avoiding the risk of breakage, a material with excellent heat resistance and chipping resistance can be used for the drill part consisting of the inner layer 7, and the life of the drill can be increased from 3000 holes to 4500 holes. Could improve on the hole.
Furthermore, since the material of the outer layer 6 is cheaper than the material of the inner layer 7, the conventional Co 6.0 wt%, TiC 1.0 wt%,
We have also succeeded in reducing the raw material cost compared to the one-piece cemented carbide with the balance WC.

(Embodiment 2) As in the previous embodiment, Co12.
Cemented carbide powder of 0 wt% and the balance WC was mixed with 7.0 wt% of paraffin and kneaded for 1 hour to form a dough.
Degassing screw extruder, outer diameter 45mm, inner diameter 22m
It was formed into a pipe having a length of m and a length of 250 mm. Then Co
Cemented carbide powder of 6.0 wt%, TiC of 1.0 wt% and the balance of WC was mixed with 7.0 wt% of paraffin to form a dough, which was formed into a rod shape with an outer diameter of 21 mm and a length of 250 mm by the same extruder. After charging both of these into the cylinder and thoroughly deaerating the air in the cylinder with a vacuum pump,
Apply a pressure of 35 kg / cm ^{2 with} a piston to obtain an outer diameter of 3.
It was extruded into a 4 mm rod shape. Then, the same heat treatment as in Example 1 was performed.

The material after sintering was rod-shaped with an outer diameter of 2.7 mm, the outer Co was 12.0 wt%, the remaining WC had a cemented carbide layer thickness of 0.7 mm, the inner Co was 6.0 wt%, and T was T.
The diameter of the cemented carbide portion of iC 1.0 wt% and the balance WC was 1.3 mm. When this material was ground to produce a drill for drilling a printed circuit board similar to that of all the examples, the same performance as that of the previous example 1 was obtained.

(Example 3) Ni 18.0 wt%, Mo1
A cermet powder of 0.0 wt% and the balance of Ti (C, N) was mixed with 4.0 wt% of paraffin, and spherically granulated powder was molded into a truncated cone shape as shown in FIG. 3 by a powder molding press. As for this dimension, the diameter of the upper surface is 15 mm, the diameter of the lower surface is 30 mm, and the height is 10 mm. After loading the lower member 8 into a cylinder having an inner diameter of 30 mm, Co
A powder obtained by spherically granulating 6.0 wt% of cemented carbide with the balance WC with 1.5 wt% of paraffin has a total filling depth of 1
Insert so that it becomes 6.2 mm. After that, a pressure of 80 kg / cm ² was applied by a piston and extruded into a rod shape having an outer diameter of 13 mm and a length of 55 mm. 10 mm in the cylinder
Thick slag remained.

Degreasing and sintering were carried out by heating hydrogen gas up to 450 ° C. at a rate of 20 ° C./hour while degreasing the paraffin, and then heating at a rate of 8 ° C./minute. It was kept at 1460 ° C. for 2 hours. The raw material after sintering is a round bar having an outer diameter of 10.5 mm and a length of 45 mm. The structure of the cermet and the cemented carbide is as shown in FIG. 4, and the lower member 8 of the cermet is deformed into a shape like 8A. This portion 8A is a portion that becomes a cutting edge or an outer peripheral portion when processed into an end mill, and a cermet having excellent heat resistance and welding resistance is suitable. Further, a cemented carbide is formed in the central portion 9 that needs toughness. Compared with conventional end mills with one body of cemented carbide, it excels in cutting performance of difficult-to-cut materials such as stainless steel, and has a life of 2000 m to 350 m.
It was possible to improve to 0 m. Further, it is possible to improve impact resistance, which is a drawback of the cermet-integrated end mill, and high price.

(Example 4) Ni 13.0 wt%, Mo
7.0 wt%, TaC 5.0 wt%, TiC 18.0 w
1% for cermet powder with t% and balance Ti (C, N)
A mixture of wt% paraffin and kneaded for 1 hour to form a mochi-shaped mixture was degassed with a screw extruder and had an outer diameter of 45 mm.
A pipe having an inner diameter of 36 mm and a length of 250 mm was formed.
Subsequently, Co 6.0 wt%, TiC 1.0 wt%, balance W
The cemented carbide powder of C is mixed with 7.0 wt% of paraffin to form a dough, and the same extruder is used to form an outer diameter of 35 mm and an inner diameter of 26 m.
It was formed into a pipe having a length of m and a length of 250 mm. Furthermore, C
o 16.0 wt%, the balance WC 7.0 w for cemented carbide powder
Paraffin of t% was mixed to form a dough, and the extruder was used to form a rod having an outer diameter of 25 mm and a length of 250 mm. As shown in FIG. 5, at the end of the cylinder 1 into which these three members are loaded,
A nozzle 10 having an outer diameter of 12.5 mm and having a drill-shaped cross section was attached, and then a pressure of 50 kg / cm ² was applied by a piston and extruded. The molded product was hydrogen gas 7.0 in the furnace.
20 ° C up to 450 ° C while flowing 1 (liter) / min
After degreasing the paraffin by heating at a speed of / hour,
The mixture was heated at a rate of ° C / min and kept at 1460 ° C for 2 hours.

The material after sintering has a drill blade shape with an outer diameter of 10.2 mm. The structure of the three kinds of materials is as shown in FIG.
When re-sintered at around ℃, outer layer 11, middle layer 12, inner layer 1
A drill material having a multilayer structure of 3 is obtained. Compared to conventional solid carbide alloy drills, it excels in cutting performance of difficult-to-cut materials such as stainless steel and has a life of 600 holes to 2
It was possible to improve to 500 holes. In addition, the shortage of toughness, which is a drawback of the cermet integrated drill, and the high price can be improved.

[0020]

As is apparent from the above description, according to the present invention, a cemented carbide containing WC as hard particles and an iron group metal as a main bonding phase, and TiC or Ti (C, N) as hard. Among the cermet alloys which have iron group metal as the main binder phase as particles, in the manufacturing method of the composite structure high humidity material in which multiple arbitrary materials are selected to form a multilayer structure, the raw materials forming the multilayer structure are charged into the cylinder. The step of extruding this from the cylinder by pushing it with a piston to form a composite structure hard material of arbitrary cross section, and the step of joining the interface by diffusion of the main binder phase in the subsequent sintering step.

Therefore, by using a press extruder and a vacuum sintering furnace which have been widely used for producing cemented carbide and cermet, a simple process requiring no new equipment or special modification can be performed. This has the effect of making it possible to obtain a hard composite material having a composite structure that is a multilayer structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a multilayer structure formed in a cylinder in an extrusion molding step in a manufacturing method according to the present invention and a multilayer structure of a molded product.

FIG. 2 is a cross-sectional view showing a drill for drilling a printed circuit board that can be manufactured by the manufacturing method according to the present invention.

FIG. 3 is a perspective view showing an inner layer material formed into a truncated cone shape by a powder forming press used in a forming step in the manufacturing method according to the present invention.

FIG. 4 is a diagram showing a structural example of a material for a composite end mill after molding a cermet and a cemented carbide in the shape of the interior material shown in FIG.

FIG. 5 is a diagram showing a configuration example of a cylinder to which a nozzle for extrusion molding a drill blade surface, which is applied to the manufacturing method according to the present invention, is attached.

FIG. 6 is a diagram showing a configuration example of a cermet and a composite drill material of two kinds of cemented carbide formed by the manufacturing method according to the present invention.

FIG. 7 is a process diagram of a conventional method for manufacturing a composite structural hard material.

[Explanation of symbols]

1: Cylinder 2: Piston 3: Nozzle 4: Outer layer 5: Inner layer 6: Outer layer of drill for drilling printed circuit board 7: Inner layer of drill for drilling printed circuit board 8: Lower member 8A: Cutting edge and outer circumference when processed into end mill Part 9: central part requiring toughness 10: nozzle having a drill-shaped cross section 11: outer layer 12: middle layer 13: inner layer 14: groove

Claims (1)

[Claims] 1. A cemented carbide containing WC as hard particles and an iron group metal as a main bonding phase, and TiC or Ti (C, N).
Among the cermet alloys with hard particles as the main binder phase of the iron group metal, in the manufacturing method of the composite structure hard material forming a multilayer structure by selecting any plural materials, the raw materials forming the multilayer structure are charged into the cylinder. Then, it is extruded from the cylinder by pushing it with a piston to form a composite structure hard material of arbitrary cross section, and a step of joining the interface by diffusion of the main binder phase in the subsequent sintering step. A method of manufacturing a hard material having a composite structure.