CN104350028A

CN104350028A - Sintered superhard compact for cutting tool applications and method of production thereof

Info

Publication number: CN104350028A
Application number: CN201380027467.9A
Authority: CN
Inventors: 托尔比约恩·塞林德; 格罗尔德·温尔; 邵锐
Original assignee: Diamond Innovations Inc
Current assignee: Diamond Innovations Inc
Priority date: 2012-05-31
Filing date: 2013-05-31
Publication date: 2015-02-11
Also published as: WO2013181525A1; EP2855399A1; KR20150024325A; US20130323107A1; JP2015523954A

Abstract

A method and a composition of a sintered superhard compact are provided. The sintered superhard compact body may comprise superhard particles and a binder phase. The binder phase may bond the superhard particles together. The binder phase comprises tungsten and cobalt. The ratio of tungsten to cobalt is between 1 and 2 and the sum of W and Co in the sintered superhard compact is in a range from about 2% to about 20% by weight.

Description

For Superhard composite film and its manufacture method of the sintering of cutting tool application

The cross reference of related application

This application claims the right of priority of the provisional application 61/653,779 that on May 31st, 2012 submits to.The application and name are called " CUTTING TOOLS MADE FROM STRESS FREE CBN COMPOSITE MATERIAL AND METHOD OF PRODUCTION " (cutting tool be made up of unstressed CBN matrix material and manufacture method) and require that the common co-pending application of the right of priority of the provisional application 61/653,699 that on May 31st, 2012 submits to is relevant.The application is called with name in addition " Method of making a cBN material " (manufacturing the method for cBN material) and require that the common co-pending application of the right of priority of the provisional application 61/653,686 that on May 31st, 2012 submits to is relevant.

Technical field

The present invention relates to the superhard material of the sintering be made up of the powder composition being applicable to manufacture super hard abrasive composite sheet, and particularly have the toughness of enhancing and the well conforming sintered compact containing cubic boron nitride (cBN), it can be used in the cutting tool for hard accessory turning application.

Background technology

Polycrystal cubic boron nitride (PcBN), diamond and diamond composite are generally used for the superhard cutting surface being provided for the cutting tool used in cutting tool such as intermetallic composite coating.

It has been generally acknowledged that, these materials described have fragility characteristic more or less, that is, in toughness, material requires that harsh operational example is as in the intermittent type processing of hardened steel, shows less desirable random fracture.A this fragility part is because Binder Phase is pottery, but also due to cBN particle and wolfram varbide abrasive dust (mill debris) dispersion not exclusively.Dispersion not exclusively causes existing in material mechanically weak parts or defect.

Therefore, the hard part processing Superhard composite film with excellent toughness feature needing all evenly as one man to disperse to require in harsh operation to be manufactured on toughness in the material, particularly use in the hard accessory turning of intermittent type or grinding.

Summary of the invention

In one embodiment, the Superhard composite film cutter hub of sintering can comprise ultra-hard particles; With Binder Phase ultra-hard particles be bonded together, in the composite sheet wherein sintered, % by weight ratio of W/Co drops between 1.0 and 2.0, and in the composite sheet of sintering % by weight summation of W and Co in the scope of about 2 to about 20.

In another embodiment, the Superhard composite film cutter hub of sintering can comprise ultra-hard particles; With the Binder Phase that ultra-hard particles is bonded together, wherein Binder Phase comprises the tungsten and cobalt that are derived from abrasive dust, and wherein Binder Phase comprises IV race in stoichiometry or substoichiometric aluminium, titanium or the periodic table of elements, the carbide of other transition metal of V race or VI race, nitride, oxide compound or its summation.

In still another embodiment, the method manufacturing Superhard composite film can comprise the following steps: provide grinding element; Powdered mixture and the fluid of superhard powder and matrix material is ground with grinding element; W and Co of self-grind body is incorporated in Superhard composite film with future.

Accompanying drawing explanation

When read in conjunction with the accompanying drawings, foregoing summary and described embodiment will be understood better following detailed description.Should be understood that described embodiment is not limited to shown accurate configuration and means.

Fig. 1 is by back-scattered scanning electron microscope (BSE) image of the microtexture of the Superhard composite film cutter hub of the sintering using the three-stage roll mill of hardmetal milling bodies to manufacture;

Fig. 2 is by back-scattered scanning electron microscope (BSE) image of the microtexture of the Superhard composite film cutter hub of the sintering using the three-stage roll mill of sintering metal grinding element to manufacture;

Fig. 3 is according to back-scattered scanning electron microscope (BSE) image of an embodiment by the microtexture of the Superhard composite film cutter hub of the sintering using the vertical ball mill of sintering metal grinding element (attritor mill) to manufacture;

Fig. 4 is compared with business grade, the figure of the wear of the tool flank process (progression) of the cutting tool manufactured by the material using the vertical ball mill of sintering metal grinding element to grind;

Fig. 5 is compared with business grade, the figure of the crater wear process of the cutting tool manufactured by the material using the vertical ball mill of sintering metal grinding element to grind; And

Fig. 6 is compared with business grade, the figure of the toughness test result of the cutting tool manufactured by the material using the vertical ball mill of sintering metal grinding element to grind.

Detailed Description Of The Invention

An embodiment provides Superhard composite film cutter hub and its manufacture method of the sintering of the W/Co with % by weight ratio determined.Ultra-hard particles is optional from cubic boron nitride, diamond and diamond composite.Comprise in powder or the cBN of particle form and Binder Phase manufacturing the feedstock composition used in polycrystalline cBN composite sheet.Binder Phase can melt at least partly and be reacted by reaction sintering and cBN and formed and bond during high pressure and high temperature (HPHT) sintering.

The cBN material that the wear resistance that embodiment can be improved to have increase and life tools, mutability reduced is for the toughness of specific application area.Superhard sintered combined provides with its manufacture method the microhomogeneity and sintered combined slice better toughness more superhard than other that significantly improve.

Embodiment uses grinding element, such as sintering metal grinding element.Sintering metal grinding element can be made up of following raw material powder adulterant, and it comprises 18 % by weight hexagonal closs packing (HCP) WC, 16%HCP Co and balance face-centered cubic (FCC) TiCN.After sintering, sintering metal grinding element can contain the W in 15% to 20% scope, during it may be dissolved in (FCC) (Ti, W) (C, N).Cermet material also can contain 15% cobalt at the most, and it can contain again 12% tungsten dissolved at the most.

CBN dispersion of particles mainly realizes during grinding steps.Usually, the grinding as pulverizing and dispersion means is as known in the art.Milling, grinding technique conventional in ceramic powder comprises conventional ball mill, rolling type ball mill, planetary ball mill, vertical ball mill and stirring ball mill.In the ball milling of routine, determine energy input by the diameter of the size of grinding medium and density, grinding pot and speed of rotation.Because the method needs spheroid to roll, so speed of rotation and therefore energy are limited.Conventional ball milling is very suitable for grinding has the low abrasive flour to median particle intensity.The ball milling of usual use routine, wherein powder is milled to about 1 micron or larger final size.

In planetary type ball-milling, the planetary motion permission acceleration of grinding pot is up to 20 times of universal gravity constant.When using fine and close grinding element, this permission produces the energy more much bigger than conventional ball mill in grinding.This technology is very suitable for the pulverizing of the particle with medium tenacity, and wherein final size is about 1 micron.

On the other hand, vertical ball mill is made up of the closed chamber of milling with agitator, and described agitator is with horizontal or vertical structure high speed rotating.Grinding element usually in the size range of 0.2 to 15mm, by pulverize for the purpose of time, grinding medium is generally high-density cemented carbide.The high rotation speed of agitator is combined with high-density, minor diameter grinding element, provides high-energy.In addition, the high-energy in vertical ball mill produces high-shear in the slurry, and this provides extremely successful being divided into fall apart or powder blend.Compared to other method mentioned, vertical ball mill realizes meticulousr particle and better material homogeneity in sintered combined usually.

An embodiment can use following vertical ball mill or other shredder, it has the grinding element manufactured by the Wimet hard metal (cemented carbide hard metal) containing 85-90%HCP WC and 7-15%Co, and described Wimet hard metal is also referred to as WC/Co hard metal.In some embodiments, the abrasive dust of desired form can allow the dispersion of milling time and the improvement more grown.As used herein, term " abrasive dust " refers to due to abrasive particle, friction between grinding element and lining and any material of producing from the lining of grinding element or shredder.During grinding, out of phase dispersion is crucial.In the prior art, the dispersion of maximum possible is subject to the restriction of the following fact: hardmetal milling bodies weares and teares and produces the abrasive dust containing high WC content.This can cause WC content in PcBN adulterant to increase with the milling time extended.This is permissible to a certain extent; But if WC content becomes too high, then it can cause the remarkable deterioration of material character.Therefore, because Wimet has the W content more much higher than sintering metal, therefore for the permissible milling time of hardmetal milling bodies well below sintering metal grinding element, this greatly limits and can be undertaken grinding the dispersion level realized by using hardmetal milling bodies.

In other embodiments, sintering metal hard metal grinding element can comprise the composition of (Ti, W) (C, N).The part that described composition can advantageously form as final base substrate and adding.Even if in other these embodiments, the starting material that also can add containing W and/or Co form to realize desired final material.In one embodiment, tungsten and cobalt are from abrasive dust.By using sintering metal grinding element, can form the abrasive dust of more favored form, wherein abrasive dust is actually a part for feedstock blends.Use sintering metal abrasive dust to be as the advantage of raw material, this abrasive dust contains (Ti, W) (C, N) and the Co of the W/Co with appropriate ratio, and they always together.In the commitment that pre-sintering process or HPHT sinter, the W in (Ti, W) (C, N) is reduced into metal W, and it is dissolved in the Co of fusing during HPHT sintering.Therefore, the Co of fusing can help W to be evenly distributed on particle periphery and help to increase the homogeneity of Co, W and the reaction between Al and cBN and Binder Phase particle.After HPHT sintering, at least some Co and W has reacted and has formed ceramic phase.

Similar to this theory, the sintering metal solid powder of sintering can also be broken into powder and it is blended together to realize identical effect with cBN and ceramic bonding phase material.On the contrary, if grind PCBN adulterant with hardmetal milling bodies, then the W from abrasive dust will too much can not be dissolved in Co.Even if add Co powder in adulterant, W and Co particle is always not adjacent one another are yet.Therefore, in microtexture, usually there is large W or WC particle, this may not be desired by processed and applied.

In one embodiment, ultra-hard particles can comprise 31 % by weight cBN, and wherein Binder Phase comprises 5 % by weight Al, 32 % by weight Ti (C _0.6n _0.4), 32 % by weight substoichiometric TiN _0.72.By using cermet body to carry out abrasive substance in vertical ball mill, obtain the add-on of W and 2.2+/-1 % by weight, 3.1+/-1 % by weight Co from grinding element.

In one embodiment, the ratio of tungsten and cobalt can in the scope of 1.0 to 2.0.In another embodiment, the ratio of tungsten and cobalt can in the scope of 1.0 to 1.8.In still another embodiment, the ratio of tungsten and cobalt can in the scope of 1.0 to 1.5.

PCBN class material for hard part turning comprises following sintered compact usually, it has the cBN particle of volume share within the scope of 35 to 85 volume %, with following ceramic bonding phase, it comprises aluminium, titanium or period of element Table IV race, the carbide of other transition metal any of V race or VI race, nitride, oxide compound or its summation.CBN class material is sintered in high pressure-temperature (HPHT) technique.Phase in version during HPHT technique such as causes producing new phase, such as boride, nitride and carbonitride.A small amount of inevitable pollutent may be present in these materials, and it can produce in specific process step is such as ground, and this causes producing the tungsten and cobalt contents that come from grinding element.

In the embodiment of method manufacturing Superhard composite film, by grinding technics by superhard starting material such as cBN and fluid and stupalith fusion, it comprises stoichiometry or substoichiometric aluminium, titanium or period of element Table IV race, the carbide of other transition metal of V race or VI race, nitride, oxide compound or its summation.An embodiment also can comprise the following steps: prepare particle from the mixture of superhard powder, ceramic powder, organic binding material and fluid; Pre-compacted particle determines the soft green component of shape to be formed; Heat soft green component in a vacuum furnace to form hard green component; One or more hard green component is inserted in container.An embodiment also can comprise the following steps: the hard green compact in pressure chamber under predetermined pressure and temperature in sintering container; Container is shifted out to expose Superhard composite film from pressure chamber.

Usually the HPHT sintering by the powder blend of cBN, ceramic phase and aluminium or aluminum compound manufactures PCBN, and usually can form large PCBN dish or " base substrate " shape.In addition, the two-phase being attributable to cBN and Binder Phase material such as can be selected from Al ₂o ₃, TiB ₂, AlN.And detect W, Co or W-Co alloy phase of at least one containing boride by X-ray diffraction (XRD), such as WB ₂, Co ₂b or CoW ₂b ₂.In some embodiments, in base substrate, W phase is not detected.

Also can be sintered by the HPHT of the hard green compact dish of pre-compacted and manufacture PCBN base substrate.Except cBN and the Binder Phase material that adds, such hard green compact have the Al that can be included in and produce in pre-sintering step ₃ti, Ti ₂alN, W, CoAl, AlB ₂mesophase spherule.

Embodiment

Embodiment 1

Embodiment A. in three-stage roll mill in Virahol with the powder mull 2 hour of hardmetal milling bodies by cBN (39 % by weight), substoichiometric TiN (ssTiN) (56 % by weight) and Al (5 % by weight).Then in an oven in atmosphere dry slurry to remove alcohol.Then by powder dispersion in ethanol (99.6% purity), it is mixed with polyoxyethylene glycol (PEG) solution.Then slurry is spray dried to spheroidal particle, its pre-compacted is become disk.This dish is carried out firing and then presintering at 900 DEG C in a vacuum in hydrogen at about 400 DEG C.After presintering, hard green compact dish is loaded in the chamber and at the temperature of about 1300 to 1450 DEG C, uses the pressure of at least 2GPa to carry out HPHT sintering.

Embodiment B. with the powder of sintering metal grinding element grinding cBN (39 % by weight), ssTiN (56 % by weight) and Al (5 % by weight) in three-stage roll mill.SsTiN and Al powder is ground 15 hours in ethanol (99.6% purity), then cBN powder is added in slurry and also grind 10 hours again.Then after grinding slurry is mixed with PEG solution.Identical with described in embodiment A of following spraying dry, pre-compacted, presintering and HPHT technique.

Embodiment C. in vertical ball mill, use sintering metal grinding element that the powder of cBN (39 % by weight), ssTiN (27 % by weight), TiCN (28 % by weight) and Al (6 % by weight) is ground 3 hours together in ethanol.Sintering metal grinding element has following composition (% by weight): W 17.36, Co17.47, Ti 50.65, N 4.84, and C 9.83.After grinding slurry is mixed with PEG solution.Identical with described in embodiment A of following spraying dry, pre-compacted, presintering and HPHT technique.

Table 1 illustrates W and the Co content obtained by XRF (XRF) of embodiment A, B and C and the summation of the W/Co ratio calculated and W and Co content.All three embodiments have identical W content (4.2 to 4.5 % by weight), but much higher than in other two kinds of situations of Co content in Embodiment C.In Embodiment B, although with sintering metal grinding element abrasive flour, because grinding element grinding has the surface of the grinding pot of WC lining, so WC abrasive dust may from WC lining and grinding element.Therefore, the comparable W/Co ratio from sintering metal grinding element of W/Co ratio is much higher.In Embodiment C, attritor mill effect determine wearing and tearing between grinding element than the serious wear from grinding pot many.Therefore, even if attritor mill tank is made up of stainless steel, the abrasive dust from attritor mill tank is also few.Iron level in final adulterant is only about 0.3 % by weight.Carry out the abrasive dust of attritor mill mainly from grinding element with sintering metal grinding element, it produces low W/Co ratio.

Fig. 1, Fig. 2 and Fig. 3 illustrate backscattered electron (BSE) Photomicrograph of embodiment A, B and C.Fig. 1 illustrates the BSE image with the embodiment A of 39 % by weight cBN ground by hardmetal milling bodies roll-type two hours.Fig. 2 illustrates the BSE image with the Embodiment B of 39 % by weight cBN ground by sintering metal grinding element roll-type 25 hours.Fig. 3 illustrates with the sintering metal grinding element attritor mill BSE image with the Embodiment C of 39 % by weight cBN of three hours.Visible under identical W content, the dispersion in embodiment A is not so good.Compared with embodiment A, the dispersion in Embodiment B and C is significantly improved.It should be noted that, in embodiment A and B, because W is excessive, therefore can see large abrasive dust (white point in Photomicrograph), and in Embodiment C, to be dissolved in Co due to W and to be evenly distributed in microtexture, therefore seldom seeing large abrasive dust.

Table 1:

Embodiment 2

Table 2 illustrates other blends of materials multiple, and it uses different grinding element (sintering metal or Wimet) and different shredder (three-stage roll mill or vertical ball mill) to grind.The lining of three-stage roll mill can be stainless steel (ss) or Wimet (cc).Except abrasive material D, all material all has the good distribution of composition, and the time length that abrasive material D is polished is too short.When grinding with cemented carbide body, because the W/Co ratio in grinding element material is high, therefore W/Co ratio the highest (being greater than 10).When carrying out roll-type grinding with cermet body, again owing to testing in the shredder with Wimet lining, therefore except sintering metal grinding element, facilitate higher than cermet material of total W/Co ratio (being such as greater than 5) from the WC abrasive dust of lining.By reaching minimum W/Co ratio with the vertical grinding of cermet body, this is because as explained above, most of abrasive dust is from sintering metal grinding element.It should be noted that, by carrying out roll-type grinding with stainless steel lining, similar low W/Co ratio can be reached.But, realize identical dispersion and W content needs the time more much longer than the situation of vertical grinding, and due to the abrasive dust from grinding pot, iron level will be quite high.

Table 2:

Embodiment 3

In vertical ball mill, use sintering metal grinding element by the powder mull 5 hours of aluminium (5 % by weight), TiCN (32 % by weight), ssTiN (32 % by weight) and cBN (31 % by weight) in ethanol.After grinding, slurry to be mixed with PEG solution and with material spray is dry with the identical mode described in embodiment 1, pre-compacted, presintering HPHT sintering.Then carry out electrospark machining (EDM) to the tip of cutting from HPHT sintering pan and manufacturer's standard cutting tool carry out processing test together with business hard part turning grade, described business hard part turning grade is hereafter, be called as " comparing grade " or " contrast " in Fig. 4, Fig. 5 and Fig. 6 and table 4.

Table 3 illustrates the XRD data of embodiment 3 after presintering and HPHT.Co and W has reacted to form several different reaction product.In material after HPHT, desired by routine, cBN, TiCN, Al detected ₂o ₃and TiB ₂.Cenotype is the tungsten of some boracics, cobalt or tungsten-cobalt phase, such as WB ₂, Co ₂b or CoW ₂b ₂.The most significantly, the such as AlB of the mesophase spherule after presintering ₂, Ti ₂alN, W are invisible after HPHT.Due to the solid-state diffusion between the TiCN/TiN binding agent during HPHT sintering and homogenizing, the TiN peak that can detect after presintering also disappears after HPHT.

Table 3:

Fig. 4 with Fig. 5 illustrates and compares compared with grade, embodiment 3 wear of the tool flank and crater wear test result.This test is carried out with continuous cutting on 8620 steel.Within every 2 to 4 minutes, stop cutting, and measure and record wear of the tool flank and crater wear.Visible embodiment 3 has the crater wear similar with comparing grade, but wear of the tool flank with compare compared with grade much lower.

Table 4 illustrates and compares compared with grade, to a series of wear testings by cutting 8620 steel that embodiment 3 is carried out.Within every 4 minutes, measure wear of the tool flank and determine life tools based on 0.15mm wear of the tool flank.Test different cutting speeds (240 and 180 ms/min), feed rate (0.1 and 0.15 millimeter/turn) and depth of cut (0.1 to 0.2 millimeter of doc).At each occurrence visible, embodiment 3 has and compares life tools longer compared with grade far away, illustrates that this material can have the possibility of widespread use.

Table 4:

Fig. 6 illustrates embodiment 3 and the toughness test result compared compared with grade.This test carries out on 52100 steel with Rc 60 to 62 hardness.Test often kind of four samples and record the fault feed rate of each sample.Routinely, toughness increases with cBN content.But can see, although embodiment 3 has and compares cBN content much lower compared with grade, be 38 volume % in embodiment 3, and to compare in grade be 50 volume %, and it has the tenacity levels identical with comparing grade, and better consistence far away.This may be owing to higher Co content and evenly abrasive dust distribution.

Although with reference to particular, it is evident that those of ordinary skill in the art can design other embodiment and variant when not deviating from purport of the present invention and scope.Appended claims is intended to be read as and comprises all such embodiments and equivalent variant thereof.

Claims

1. a Superhard composite film cutter hub for sintering, it comprises:

Ultra-hard particles; With

By the Binder Phase that described ultra-hard particles is bonded together, wherein said Binder Phase comprises W and Co, in the Superhard composite film of wherein said sintering, % by weight ratio of W/Co drops between 1.0 and 2.0, and in the Superhard composite film of described sintering W and Co % by weight summation in the scope of about 2.0 to about 20.

2. the Superhard composite film cutter hub of sintering according to claim 1, wherein said ultra-hard particles is selected from cubic boron nitride, diamond and diamond composite.

3. the Superhard composite film cutter hub of the sintering according to aforementioned claim 1 to 2, it also comprises the carbide of other metal in the transition element of stoichiometric aluminium, titanium or period of element Table IV race, V race and VI race, nitride, oxide compound or its summation.

4. the Superhard composite film cutter hub of the sintering according to aforementioned claims 1 to 3, it also comprises the carbide of other metal in the transition element of substoichiometric aluminium, titanium or period of element Table IV race, V race and VI race, nitride, oxide compound or its summation.

5. the Superhard composite film cutter hub of the sintering according to aforementioned Claims 1-4, wherein the ratio of tungsten and cobalt is in the scope of 1.0 to 1.8.

6. the Superhard composite film cutter hub of the sintering according to aforementioned claim 1 to 5, wherein the ratio of tungsten and cobalt is in the scope of 1.0 to 1.5.

7. the Superhard composite film cutter hub of the sintering according to aforementioned claim 1 to 6, it also comprises the tungsten of at least one boracic, cobalt or tungsten-cobalt phase, as by X-ray diffraction (XRD) detect.

Comprise at least one and be selected from WB ₂, Co ₂b or CoW ₂b ₂phase, as by X-ray diffraction (XRD) detect.

9. the Superhard composite film cutter hub of the sintering according to aforementioned claim 1 to 8, wherein can't detect tungsten or wolfram varbide by X-ray diffraction (XRD).

10. the Superhard composite film cutter hub of the sintering according to aforementioned claim 1 to 9, wherein said tungsten and cobalt are the abrasive dusts from grinding element.

11. 1 kinds of methods manufacturing Superhard composite film, described method comprises:

Grinding element is provided;

Superhard powder, the powdered mixture of matrix material and fluid is ground with described grinding element; With

To be incorporated in described Superhard composite film from the cobalt of described grinding element and tungsten, wherein said grinding element is low W content grinding element.

The method of 12. manufacture Superhard composite films according to claim 11, it also comprises prepares particle from the mixture of superhard powder blend, organic binding material and fluid.

13. according to claim 11 to the method for the manufacture Superhard composite film described in 12, and it also comprises particle described in pre-compacted to form the soft green component determining shape.

The method of 14. manufacture Superhard composite films according to claim 13, it also comprises and heats described soft green component in a vacuum furnace to form hard green component.

15. according to claim 11 to the method for the manufacture Superhard composite film described in 14, and it also comprises and one or more described hard green component being inserted in container.

16. according to claim 11 to the method for the manufacture Superhard composite film described in 15, and it is also included in pressure chamber and sinters described container under predetermined pressure and temperature.

17. according to claim 11 to the method for the manufacture Superhard composite film described in 16, and it also comprises shift out described container to expose described Superhard composite film from described pressure chamber.

18. according to claim 11 to the method for the manufacture Superhard composite film described in 17, and wherein said superhard powder comprises the material being selected from cubic boron nitride, diamond and diamond composite.

19. according to claim 11 to the method for the manufacture Superhard composite film described in 18, and wherein said particle comprises the mixture of the polyoxyethylene glycol organic binding material of cubic boron nitride and aluminium.

20. according to claim 11 to the method for the manufacture Superhard composite film described in 19, and wherein said powdered mixture comprises compound containing W and Co to realize desired composition.