JP2927098B2 - Physical vapor deposited hard layer coated drill and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a physical vapor-deposited hard layer-coated drill excellent in peel resistance and fracture resistance and a method for producing the same.

[0002]

2. Description of the Related Art A Co binder phase is contained as a binder phase forming component, and if necessary, a periodic table 4a, 5a and 6
Forming a hard coating layer by physical vapor deposition on the surface of a WC-based cemented carbide drill base containing one or two or more carbides of a group a metal and the remainder consisting of tungsten carbide (hereinafter referred to as WC) and unavoidable impurities Hard layer coated drills are known.

[0003] This hard layer-coated drill is usually manufactured by cleaning the surface of a WC-based cemented carbide drill base by bombard cleaning and then forming a hard coating layer by physical vapor deposition.

[0004]

However, a WC obtained by bombarding a normal WC-based cemented carbide drill base is used.
The physical vapor-deposited hard coating layer formed on the surface of the base cemented carbide drill substrate does not have sufficient adhesion strength. Further, if the bombarding cleaning time is extended to increase the adhesion strength and the substrate temperature is increased, the WC base As shown in FIG. 2, the surface of the hard alloy drill substrate was partially sputtered with the Co bonding phase 1 at the cutting edge and disappeared.
WC as if etching the surface of the base cemented carbide drill base
When the concave portion 2 is formed on the surface of the base cemented carbide drill base and the outermost surface layer is roughened and the physical vapor deposition hard coating layer 3 is formed thereon, the adhesion strength of the hard coating layer is improved, but the concave portion becomes a hole. However, it has been found that the hole serves as a starting point of destruction, which tends to cause chipping and loss.

[0005]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of conducting research to obtain a hard layer coated drill having a long tool life, which has excellent adhesion strength of the physical vapor deposition hard coating layer to the surface of a cemented carbide drill substrate and does not cause chipping or chipping early in cutting, (a ) The raw material powder is blended so as to have a predetermined blending ratio,
The round bar green compact obtained by mixing and extruding is primarily sintered in a normal vacuum or low-pressure inert gas to produce a round bar primary sintered body. The primary sintered body of the drill shape is manufactured by grinding to a predetermined drill shape, and the primary sintered body of the drill shape is further subjected to a liquid phase appearance temperature of 1500 ° C. or more in an inert gas atmosphere at a pressure of 5 to 1000 atm. Secondary sintering under conditions within the temperature range described above to produce a drill-shaped secondary sintered body, and using the drill-shaped secondary sintered body as a substrate, the surface thereof is coated with a physical vapor-deposited hard layer by an ordinary method. The resulting physical vapor-deposited hard layer-coated drill has excellent adhesion strength of the physical vapor-deposited hard coating layer to the surface of the cemented carbide substrate and does not cause chipping or chipping in a short time during cutting.

(B) The surface layer of the drill-shaped secondary sintered body obtained by the secondary sintering is, as shown in FIG.
Co-coupling phase deficient layer 4 having a bonding phase amount of 3/5 or less of the average composition of the base material and having a thickness of 5 μm or less, and a thickness of 10 μm at which the Co bonding phase concentration gradually increases from the Co-coupling phase deficient layer 4 toward the inside.
m or less, and the amount of the Co bonded phase is 3/5 or less of the average composition of the substrate and the thickness is 5 μm.
m or less, the Co-bonded phase-deficient layer contains one or more kinds of carbides of metals of the Group 4a, 5a and 6a of the periodic table and W
Since C6 forms a particularly dense layer on the outermost surface, even if the Co-bound phase-deficient layer of the drill-shaped secondary sintered body is sufficiently bombarded for a long time, the concave portion 2 as shown in FIG.
Did not occur.

[0007] The present invention has been made based on such findings, and contains a Co binder phase: 4 to 20% by weight,
Further, if necessary, one or more of carbides of metals of Groups 4a, 5a and 6a of the periodic table are contained, and the remainder is WC
And a hard layer-coated drill in which a physical vapor deposition hard coating layer is formed on the surface of a WC-based cemented carbide drill substrate composed of unavoidable impurities.
C having a composition in which the content of Co binder phase 1 is not more than 3/5 of the average composition of the substrate and having a thickness within 5 μm from the surface.
an o-coupling phase deficient layer 4, a Co-coupling phase concentration gradient layer 5 having a thickness of 10 μm or less having a Co-coupling phase concentration gradient in which the Co-coupling phase concentration gradually increases inward from the Co-coupling phase deficient layer; The physical vapor deposition hard coating layer 3 is characterized by a physical vapor deposition hard layer coating drill formed on the Co binder phase deficient layer 4,

[0008] Further, Co contains 4 to 20% by weight,
Further, if necessary, one or two or more carbides of metals of groups 4a, 5a and 6a of the periodic table are contained, and the remainder is W
A primary sintered body of a round bar is manufactured by primary sintering a round bar-shaped green compact having a composition of C and unavoidable impurities under normal conditions, and the primary sintered body of the round bar is ground into a predetermined drill shape. To produce a drill-shaped primary sintered body. The drill-shaped primary sintered body is further subjected to a pressure: in an inert gas atmosphere at a pressure of 5 to 1000 atm and a temperature in a temperature range from a liquid phase appearance temperature to 1500 ° C. or higher. Secondary sintering produces a drill-shaped secondary sintered body, and the method is characterized by a physical vapor-deposited hard layer coated drill that forms a hard coating layer on the surface of the drill-shaped secondary sintered body by physical vapor deposition. Have

[0009] The secondary sintered body has a Co content of 4 to 20% by weight.
And, if necessary, one or more of carbides of metals of Groups 4a, 5a and 6a of the periodic table, and the remainder: having a component composition consisting of WC and unavoidable impurities and having a predetermined shape A commercially available WC-based cemented carbide drill was used as a primary sintered body, and this was further subjected to a pressure of 5 to 100.
In an inert gas atmosphere at 0 atm, above the liquid phase appearance temperature 150
It can also be obtained by secondary sintering within a temperature range of 0 ° C.

The conditions for the secondary sintering are such that if the pressure in the inert gas atmosphere is less than 5 atm, the effect is not sufficient, while if the pressure exceeds 1000 atm, deformation tends to occur, and It is not preferable because outside products can be formed. Further, the sintering temperature is in a temperature range of a liquid phase appearance temperature or higher and 1500 ° C., which is within a normal sintering temperature range.

The physical vapor-deposited hard layer of the drill coated with a physical vapor-deposited hard layer according to the present invention is a layer having a Co-bonded phase deficient layer in which the amount of Co-bonded phase at the joint with the WC-based cemented carbide drill substrate is 3/5 or less of the average composition of the substrate. And very strongly adheres to the surface of the WC-based cemented carbide drill substrate through a Co-coupled phase concentration gradient layer having a thickness of 10 μm or less in which the concentration of the Co-bonded phase gradually increases toward the inside. The toughness itself is also excellent.

If the amount of the Co bonding phase in the portion of the Co bonding phase-deficient layer that is bonded to the hard coating layer exceeds 3/5 of the average composition of the substrate, the adhesion strength of the hard coating layer decreases, which is not preferable. If the thickness of the Co-bonding phase-deficient layer exceeds 5 μm, the WC-based cemented carbide drill base is liable to break, and if the thickness of the Co-bonding phase concentration layer exceeds 10 μm, it deforms during cutting and functions well. It is not preferable because it disappears.

[0013]

[Examples] As raw material powders, all had an average particle size of 0.5 to
WC powder, TiC powder in the range of 3.0 μm, (Ti,
Ta) C powder and Co powder are prepared, and these raw material powders are blended so as to have a ratio shown in Table 1, and the obtained blended powder is wet-mixed for 72 hours by a ball mill, dried, and then extruded by an extrusion press. The green compact was formed into a round bar-shaped green compact, and the green compact was subjected to primary sintering under ordinary conditions, to produce round bar primary sintered bodies A to C having almost the same component composition as the above composition.

[0014]

[Table 1]

The surfaces of these round rod primary sintered bodies A to C are ground and shaped into a drill shape having an outer diameter of 8.5 mm to produce a drill-shaped primary sintered body. The drill-shaped primary sintered body was secondarily sintered under the conditions shown in Tables 2 to 4, and the resulting secondary sintered body was used as a WC-based cemented carbide drill base.

The WC-base cemented carbide drill base is mounted above the reaction furnace of a conventional ion plating apparatus, while the crucible installed below the reaction furnace of the above-mentioned ion plating apparatus has Ti inside. A metal is filled, and in this state, the inside of the reactor of the ion plating apparatus is 1 × 10
^-5 Torr vacuum, and heating rate: 6 ° C./min.
Then, while maintaining the temperature, the Ar gas was supplied from the mass flow controller through the reaction gas inlet, and the bombard cleaning was performed while maintaining the Ar gas atmosphere at 5 × 10 ⁻² Torr.

Then, the Ti metal is heated and evaporated by an electron beam, and nitrogen gas and / or
Alternatively, acetylene gas was introduced to maintain the pressure in the reaction furnace of the ion plating apparatus at 2 × 10 ⁻⁴ Torr, and coated with the physical vapor-deposited hard layer shown in Tables 2 to 4, and the coated drills of the present invention 1 to 20 and Comparative Example The coated drills 1 to 6 were manufactured, and the Co content and thickness of the Co binder phase deficient layer of the WC-based cemented carbide drill base immediately below the physical vapor deposition hard layer of these drills, and C
The thickness of the Co binder phase concentration gradient layer where the o binder phase concentration gradually increased was measured, and the results are shown in Tables 2 to 4.

For further comparison, the above drill-shaped primary sintered body B was mounted above the inside of the reaction furnace of the ion plating apparatus without secondary sintering, and was similarly bombarded and cleaned. To produce a conventional coated drill.

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

With respect to the coated drills 1 to 20 of the present invention, the comparative coated drills 1 to 6 and the conventional coated drill, a cutting speed: 40 m / min. Drill rotation speed: 1500 r. p. m. Feed: 0.2 mm / rev. A drilling test was performed to drill 300 holes in a 32.5 mm thick SCM440 work material under the following drilling conditions (total cutting length was 9.75 m at this time), and the main cutting edge at the tip of the drill was worn. The amount was measured and the cutting edge condition was observed. The results are shown in Tables 5 to 7.

[0023]

[Table 5]

[0024]

[Table 6]

[0025]

[Table 7]

[0026]

From the results shown in Tables 2 to 7, in the drilling test, the coated drills 1 to 20 of the present invention have a small wear width of the main cutting edge at the tip of the drill, and the wear condition shows normal wear. On the other hand, it can be seen that the comparative coated drills 1 to 6 and the conventional drills manufactured by the method deviating from the conditions of the present invention show abnormal wear due to minute defects or peeling.
As described above, the physical vapor-deposited hard layer-coated drill of the present invention has excellent wear resistance and fracture resistance, so that it can exhibit excellent cutting performance over a long period of time, and has excellent industrial effects. It is.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a structure of a substrate surface of a physical vapor-deposited hard layer-coated drill of the present invention.

FIG. 2 is a structural explanatory view of a substrate surface of a conventional physical vapor deposition hard layer-coated drill.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Co bonding phase 2 Depression 3 Physical vapor-deposited hard layer coating layer 4 Co bonding phase deficient layer 5 Co bonding phase concentration gradient layer 6 Periodic table 4a, 5a, and 6a group 1 metal carbide
Species or two or more and WC

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B23B 51/00 B23P 15/28 B23P 15/32 C23C 14/06

Claims (2)

(57) [Claims] Claims 1. An average composition of a base material containing Co: 4 to 20% by weight, and if necessary, one or more kinds of carbides of metals of Group 4a, 5a and 6a in the periodic table,
A hard layer-coated drill in which a physical vapor-deposited hard coating layer is formed on the surface of a WC-based cemented carbide drill substrate, the remainder of which is made of tungsten carbide (hereinafter referred to as WC) and unavoidable impurities. Is a Co binder phase having a composition having a content of a binder phase containing Co as a main component (hereinafter referred to as a Co binder phase) of 3/5 or less of the average composition of the substrate and having a thickness within a range of 5 μm from the surface. Co-phase having a thickness of 10 μm or less having a Co-binding phase concentration gradient in which the Co-binding phase concentration gradually increases from the Co-binding phase-deficient layer toward the inside.
A physical vapor deposition hard layer coating drill, wherein the drill is coated with a binder phase concentration gradient layer, and the physical vapor deposition hard coating layer is formed on the Co binder phase deficient layer. 2. The composition according to claim 1, wherein the composition contains Co in an average composition of 4 to 20% by weight, and further contains one or more carbides of metals of Group 4a, 5a and 6a of the periodic table, if necessary.
The round bar-shaped green compact having a composition consisting of WC and unavoidable impurities is primarily sintered under normal conditions to produce a round bar primary sintered body, and the round bar primary sintered body is formed into a predetermined drill shape. Grinding is performed to produce a drill-shaped primary sintered body, and this drill-shaped primary sintered body is further subjected to a condition in an inert gas atmosphere at a pressure of 5 to 1000 atm and in a temperature range of a liquid phase appearance temperature or higher and 1500 ° C. Physically deposited hard layer coating characterized by producing a drill-shaped secondary sintered body by secondary sintering under the condition, and forming a hard coating layer on the surface of the drill-shaped secondary sintered body by physical vapor deposition. Drill manufacturing method.