JP4960126B2

JP4960126B2 - Brazing cBN tool

Info

Publication number: JP4960126B2
Application number: JP2007082453A
Authority: JP
Inventors: 謙二野田
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2007-03-27
Filing date: 2007-03-27
Publication date: 2012-06-27
Anticipated expiration: 2027-03-27
Also published as: JP2008238337A

Description

本発明は、超硬合金製の台金の所定位置にロウ材を介してｃＢＮ焼結体をロウ付け接合したロウ付けｃＢＮ工具に関する。 The present invention relates to a brazed cBN tool in which a cBN sintered body is brazed and joined to a predetermined position of a base metal made of cemented carbide through a brazing material.

ｃＢＮ焼結体を工具として用いる場合、ＷＣ−Ｃｏ系超硬合金製の裏打板上にｃＢＮ焼結体の原料粉末を載置して超高圧焼成により０．５〜２．０ｍｍ程度の厚みを持つｃＢＮ焼結体の工具素材（ブランク）を作製し、これを所定の形状に切り出して超硬合金製の台金の刃先部分にロウ付けする方法が知られている（例えば特許文献１参照）。 When a cBN sintered body is used as a tool, a raw material powder of the cBN sintered body is placed on a backing plate made of a WC-Co cemented carbide, and a thickness of about 0.5 to 2.0 mm is obtained by ultra-high pressure firing. A method is known in which a tool material (blank) of a cBN sintered body is prepared, cut into a predetermined shape, and brazed to the cutting edge portion of a cemented carbide base metal (see, for example, Patent Document 1). .

かかるｃＢＮ焼結体が好適に用いられる焼入れ鋼の切削加工では、加工面粗度を平滑化することが重視される精密加工や刃先の突発欠損が発生しない安定加工が求められ、そのためにｃＢＮ原料粉末の粒径を小さくしてｃＢＮ焼結体中のｃＢＮ粒子を微粒化することが試みられている。そして、このようにｃＢＮ原料粉末を微粒化すると焼結時の収縮が大きくなるが、超高圧焼成では加圧圧力が局所的に不均一であることから焼成時にｃＢＮ焼結体中にマイクロクラックが発生してしまい、このマイクロクラックを起点として切削加工時にｃＢＮ工具が欠損するという問題があった。 In the cutting of hardened steel in which such a cBN sintered body is suitably used, precision processing that places importance on smoothing the surface roughness and stable processing that does not cause sudden chipping of the cutting edge are required. Attempts have been made to reduce the particle size of the powder to atomize the cBN particles in the cBN sintered body. And when the cBN raw material powder is atomized in this way, the shrinkage during sintering increases, but in ultrahigh-pressure firing, the pressurization pressure is locally uneven, so that microcracks are present in the cBN sintered body during firing. There is a problem that the cBN tool is lost at the time of cutting with the micro crack as a starting point.

そこで、特許文献２では、平均粒径が２μｍ未満のｃＢＮ粒子のｃＢＮ焼結体からなる切刃部を超硬合金製の台金にロウ付けする際に、台金の表面に粒径が２μｍより大きいｃＢＮ粉末と焼結助剤粉末との混合物を敷き、その上に平均粒径２μｍ未満のｃＢＮ原料粉末を含む成形体を載置して超高圧焼結して、ｃＢＮ焼結体製の切刃部と超硬合金製の台金との間に平均粒径２〜１０μｍのｃＢＮ粒子からなる中間部を形成したロウ付けｃＢＮ工具が開示され、台金の超硬合金中のＣｏが多量にｃＢＮ焼結体側に溶浸して両者の界面に脆いＣｏ化合物が生成することを抑制し、切刃部の欠けやチッピングの発生を抑制できることが記載されている。
特開２００７−３００９６号公報特開平４−６３６０７号公報 Therefore, in Patent Document 2, when a cutting edge portion made of a cBN sintered body of cBN particles having an average particle size of less than 2 μm is brazed to a cemented carbide base metal, the surface diameter of the base metal is 2 μm. A mixture of a larger cBN powder and a sintering aid powder is laid, and a molded body containing a cBN raw material powder having an average particle size of less than 2 μm is placed on the mixture and then sintered at an ultrahigh pressure. A brazed cBN tool is disclosed in which an intermediate portion made of cBN particles having an average particle diameter of 2 to 10 μm is formed between a cutting edge portion and a cemented carbide base metal, and a large amount of Co in the cemented carbide alloy of the base metal is disclosed. Describes that it is possible to suppress the occurrence of a brittle Co compound at the interface between the two by infiltrating to the cBN sintered body side, and to suppress the occurrence of chipping or chipping at the cutting edge.
Japanese Patent Laid-Open No. 2007-30096 JP-A-4-63607

しかしながら、特許文献２に記載されるように、平均粒径２μｍ未満のｃＢＮ焼結体製の切刃部と超硬合金製の台金との間に平均粒径２〜１０μｍのｃＢＮ粒子からなるｃＢＮ焼結体製の中間部を形成したロウ付けｃＢＮ工具では、Ｃｏの溶浸はないので界面に脆いＣｏ化合物が生成されることはないものの、超硬合金製台金ごと超高圧焼成する必要があることから不経済であり、かつ焼成時の熱収縮差が大きくて切刃部と中間部との界面に大きな歪みが生じてしまい、過酷な切削条件では剥離や欠損が発生するという問題があった。 However, as described in Patent Document 2, it is composed of cBN particles having an average particle diameter of 2 to 10 μm between a cBN sintered body cutting blade portion having an average particle diameter of less than 2 μm and a cemented carbide base metal. In brazed cBN tools formed with an intermediate part made of a cBN sintered body, there is no infiltration of Co, so that no brittle Co compound is generated at the interface. This is uneconomical, and the heat shrinkage difference during firing is large, resulting in large distortion at the interface between the cutting edge and the intermediate part, which causes peeling and chipping under severe cutting conditions. there were.

本発明は、上記課題を解消し、ｃＢＮ焼結体製の切刃部と超硬合金製の台金との接合強度の高いロウ付けｃＢＮ工具を提供することを目的とする。 An object of the present invention is to solve the above-mentioned problems and to provide a brazing cBN tool having high bonding strength between a cutting edge portion made of a cBN sintered body and a base metal made of cemented carbide.

本発明のロウ付けｃＢＮ工具は、切刃を有するｃＢＮ焼結体の下面に接合した裏打板を超硬合金製の台金の所定位置にロウ付け接合したロウ付けｃＢＮ工具において、前記裏打板の前記ｃＢＮ焼結体側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の５０面積％以上を含むＷＣ粒子を鉄族金属１２〜３０面積％で結合した超硬合金からなり、該裏打板の前記ロウ材側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合した超硬合金からなることを特徴とする。 The brazing cBN tool of the present invention is a brazing cBN tool in which a backing plate joined to a lower surface of a cBN sintered body having a cutting blade is brazed and joined to a predetermined position of a cemented carbide base metal. The cBN sintered body side is made of a cemented carbide in which WC particles having a corner radius of curvature of 0.1 μm or more are combined with WC particles including 50% by area or more of all WC particles with 12 to 30% by area of an iron group metal, The brazing material side of the backing plate is made of a cemented carbide in which WC particles having a corner radius of curvature of 0.1 μm or more are combined with WC particles of 20% by area or less of the total WC particles by 8-30% by area of iron group metal. It is characterized by becoming.

また、本発明の他のロウ付けｃＢＮ工具は、切刃を有するｃＢＮ焼結体からなる繊維状の芯材の周囲を硬質焼結体にて結合したｃＢＮ複合焼結体の下面に接合した裏打板を超硬合金製の台金の所定位置にロウ付け接合したロウ付けｃＢＮ工具において、前記裏打板の前記ｃＢＮ複合焼結体側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の５０面積％以上を含むＷＣ粒子を鉄族金属１２〜３０面積％で結合した超硬合金からなり、該裏打板の前記ロウ材側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合した超硬合金からなることを特徴とする。 Another brazing cBN tool of the present invention is a backing bonded to the lower surface of a cBN composite sintered body in which the periphery of a fibrous core made of a cBN sintered body having a cutting edge is bonded with a hard sintered body. In a brazing cBN tool in which a plate is brazed and joined to a predetermined position of a cemented carbide base metal, the WC particles having a corner radius of curvature of 0.1 μm or more are all WC on the cBN composite sintered body side of the backing plate. WC particles comprising a cemented carbide in which WC particles containing 50% by area or more of particles are bonded with 12 to 30% by area of iron group metal, and the brazing material side of the backing plate has a corner radius of curvature of 0.1 μm or more. Is composed of a cemented carbide in which WC particles of 20% by area or less of all WC particles are bonded with 8 to 30% by area of iron group metal.

ここで、上記構成において、前記台金が、角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合している超硬合金からなることが望ましい。 Here, in the above configuration, the base metal is formed by binding WC particles having a corner radius of curvature of 0.1 μm or more to 20% by area or less of the total WC particles by 8 to 30% by area of the iron group metal. It is desirable to be made of a cemented carbide.

本発明によれば、ｃＢＮ焼結体、またはｃＢＮ焼結体からなる繊維状の芯材の周囲を硬質焼結体にて結合したｃＢＮ複合焼結体と前記ロウ材との間に配設する超硬合金製の裏打板として、ｃＢＮ焼結体側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の５０面積％以上を含むＷＣ粒子を鉄族金属１２〜３０面積％で結合した超硬合金からなり、ロウ材側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合した超硬合金からなる構成とすることによって、ｃＢＮ焼結体およびｃＢＮ複合焼結体と裏打板との界面において超高圧焼成時に発生する残留応力を吸収することができてｃＢＮ焼結体およびｃＢＮ複合焼結体と裏打板との界面にクラックが発生することを抑制できるとともに、超高圧焼成における加圧圧力ムラによってもｃＢＮ焼結体またはｃＢＮ複合焼結体にクラックが発生することなく安定した工具性能を発揮する。 According to the present invention, a cBN sintered body or a fibrous core material made of a cBN sintered body is disposed between the cBN composite sintered body obtained by bonding the periphery of the fibrous core material with a hard sintered body and the brazing material. As a backing plate made of cemented carbide, WC particles containing 50% by area or more of WC particles having a radius of curvature of the corner portion of 0.1 μm or more on the cBN sintered body side are 12-30 area% of iron group metal. It is made of cemented cemented carbide, and the brazing material side is a super WC particle having a corner radius of curvature of 0.1 μm or more and WC particles of 20% by area or less of all WC particles combined with 8-30% by iron group metal. By adopting a structure made of a hard alloy, it is possible to absorb the residual stress generated at the time of ultra-high pressure firing at the interface between the cBN sintered body and the cBN composite sintered body and the backing plate, and the cBN sintered body and the cBN composite sintered body. Cracks at the interface between the bonded body and the backing plate In addition to being suppressed, the cBN sintered body or the cBN composite sintered body exhibits stable tool performance without generating cracks due to uneven pressure applied during ultra-high pressure firing.

ここで、台金が、角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合している超硬合金からなることが、台金の塑性変形を抑制できるとともに、ロウ材との密着力が高い点で望ましい。 Here, the base metal is made of a cemented carbide in which WC particles having corner radii of curvature of 0.1 μm or more are bonded with WC particles of 20% by area or less of all WC particles with 8 to 30% by area of iron group metal. This is desirable in that it can suppress plastic deformation of the base metal and has high adhesion to the brazing material.

以下、本発明のロウ付けｃＢＮ工具の一実施態様について図面を基に詳細に説明する。 Hereinafter, an embodiment of the brazing cBN tool of the present invention will be described in detail with reference to the drawings.

図１、２はそれぞれｃＢＮ焼結体とｃＢＮ複合焼結体を切刃部に用いた切削工具を示し、図１、２（ａ）は概略斜視図、図１、２（ｂ）は部分断面図である。 1 and 2 show a cutting tool using a cBN sintered body and a cBN composite sintered body as a cutting edge part, respectively, FIGS. 1 and 2 are schematic perspective views, and FIGS. FIG.

図１、２の切削工具１、２１は、平板状をなし、台金２の角部に形成された取付座３には、裏打板４、２４とｃＢＮ焼結体５またはｃＢＮ複合焼結体２５とが一体化された切刃チップ６、２６がロウ材７にて台金２にロウ付けされている。また、この切削工具１、２１によれば、すくい面８、２８と横逃げ面９、２９との交差稜線部に切刃１０、３０が構成されている。さらに、切削工具１、２１の中央部には、バイトなどの工具に取り付けるためのクランプねじ等が挿通される取付孔１１が形成されている。すなわち、切刃チップ６、２６はｃＢＮ焼結体５またはｃＢＮ複合焼結体２５を超硬合金からなる裏打板４、２４の表面に接合したものである。 The cutting tools 1 and 21 of FIGS. 1 and 2 have a flat plate shape, and the mounting seat 3 formed at the corner of the base metal 2 has the backing plates 4 and 24 and the cBN sintered body 5 or the cBN composite sintered body. Cutting blade tips 6, 26 integrated with 25 are brazed to the base metal 2 with a brazing material 7. Moreover, according to this cutting tool 1,21, the cutting blades 10 and 30 are comprised in the intersection ridgeline part of the rake surfaces 8 and 28 and the side flank surfaces 9 and 29. FIG. Further, an attachment hole 11 through which a clamp screw or the like for attaching to a tool such as a cutting tool is inserted is formed at the center of the cutting tools 1 and 21. That is, the cutting edge tips 6 and 26 are obtained by bonding the cBN sintered body 5 or the cBN composite sintered body 25 to the surfaces of the backing plates 4 and 24 made of a cemented carbide.

ここで、図３にｃＢＮ焼結体５およびｃＢＮ複合焼結体２５とロウ材７との間に配設する裏打板４、２４の構成を示す。裏打板４、２４をなす超硬合金３１、３６は、ＷＣ粒子３２を鉄族金属３３で結合した構成からなる。そして、図３によれば、裏打板４、２４のｃＢＮ焼結体５およびｃＢＮ複合焼結体２５側（以下、裏打板ｃＢＮ側４ａ、２４ａと称す。）は角部の曲率半径が０．１μｍ以上のＷＣ粒子３４が全ＷＣ粒子３２の５０面積％以上を含む（以下、この比率を丸いＷＣ粒子３４の比率と称す。）ＷＣ粒子３２を鉄族金属３３の１２〜３０面積％で結合した超硬合金３１で構成されており（図３（ａ）参照）、裏打板４、２４のロウ材７側（以下、裏打板ロウ材側４ｂ、２４ｂと称す。）は丸いＷＣ粒子３４の比率が２０面積％以下のＷＣ粒子３２を鉄族金属３３の８〜３０面積％で結合した超硬合金３６で構成されている（図３（ｂ）参照）。 Here, FIG. 3 shows the configuration of the backing plates 4 and 24 disposed between the cBN sintered body 5 and the cBN composite sintered body 25 and the brazing material 7. The cemented carbides 31 and 36 forming the backing plates 4 and 24 have a structure in which the WC particles 32 are bonded with the iron group metal 33. 3, according to the cBN sintered body 5 and the cBN composite sintered body 25 side of the backing plates 4 and 24 (hereinafter referred to as the backing plate cBN side 4a and 24a), the corner has a radius of curvature of 0. The WC particles 34 of 1 μm or more include 50 area% or more of the total WC particles 32 (hereinafter, this ratio is referred to as the ratio of the round WC particles 34). The WC particles 32 are combined with 12 to 30 area% of the iron group metal 33. 3 (see FIG. 3A), and the brazing material 7 side of the backing plates 4 and 24 (hereinafter referred to as the backing plate brazing material sides 4b and 24b) is formed of round WC particles 34. It is composed of a cemented carbide 36 in which WC particles 32 having a ratio of 20 area% or less are bonded with 8 to 30 area% of the iron group metal 33 (see FIG. 3B).

これによって、ｃＢＮ焼結体５と裏打板４との界面およびｃＢＮ複合焼結体２５と裏打板２４との界面において焼成収縮時および冷却時に発生する残留応力を吸収することによってこれらの界面にクラックが発生することを抑制できるとともに、超高圧焼成による加圧圧力ムラを低減して焼結ムラによるクラックの発生も抑制できる。 As a result, the interface between the cBN sintered body 5 and the backing plate 4 and the interface between the cBN composite sintered body 25 and the backing plate 24 absorb residual stress generated at the time of firing shrinkage and cooling, thereby cracking these interfaces. The generation of cracks due to sintering unevenness can be suppressed by reducing pressurization pressure unevenness due to ultra-high pressure firing.

すなわち、裏打板ｃＢＮ側４ａ、２４ａにおいて丸いＷＣ粒子３４の比率が５０面積％未満であると、残留応力を吸収する働きが弱くてクラックの進展を抑制する効果がなく、切刃チップ６、２６のチッピングや剥離につながる。また、裏打板ｃＢＮ側４ａ、２４ａにおいて鉄族金属３３の含有比率が１２面積％よりも少ないと、ｃ裏打板ｃＢＮ側４ａ、２４ａ付近の界面にＣｏ欠乏層が形成されてしまい、これらの界面からチッピングや剥離が発生するおそれがある。さらに、裏打板ｃＢＮ側４ａ、２４ａにおいて鉄族金属３３の含有比率が３０面積％よりも多いと、鉄族金属３３の拡散がｃＢＮ焼結体５およびｃＢＮ複合焼結体２５全体へ進行し、焼結体５、２５の耐摩耗性を低下させるという不具合がある。一方、裏打板４、２４のロウ材７側において丸いＷＣ粒子３４の比率が２０面積％より多い割合で存在すると超高圧焼成時の圧力ムラによって裏打板４、２４の変形が発生してしまい、鉄族金属３３の含有割合が８〜３０面積％から外れると熱膨張係数差による残留応力が大きくなり、裏打板４、２４内にクラックが発生する。 That is, if the ratio of the round WC particles 34 on the backing plate cBN side 4a, 24a is less than 50% by area, the function of absorbing the residual stress is weak and there is no effect of suppressing the progress of cracks, and the cutting edge tips 6, 26 Leading to chipping and peeling. Further, if the content ratio of the iron group metal 33 is less than 12 area% in the backing plate cBN side 4a, 24a, a Co-deficient layer is formed at the interface in the vicinity of the c backing plate cBN side 4a, 24a. There is a risk of chipping and peeling. Furthermore, when the content ratio of the iron group metal 33 is larger than 30 area% on the backing plate cBN side 4a, 24a, the diffusion of the iron group metal 33 proceeds to the entire cBN sintered body 5 and the cBN composite sintered body 25, There is a problem that the wear resistance of the sintered bodies 5 and 25 is lowered. On the other hand, if the ratio of the round WC particles 34 is larger than 20 area% on the brazing material 7 side of the backing plates 4 and 24, deformation of the backing plates 4 and 24 occurs due to pressure unevenness during ultra-high pressure firing, When the content ratio of the iron group metal 33 deviates from 8 to 30 area%, the residual stress due to the difference in thermal expansion coefficient increases, and cracks are generated in the backing plates 4 and 24.

なお、本発明における超硬合金３１と３６中のＷＣ粒子３２の角部の曲率半径とは、図３に示すように、裏打板４、２４の逃げ面側の表面または逃げ面に平行な断面に位置する超硬合金３１、３６の走査型電子顕微鏡観察において、それぞれのＷＣ粒子３２を横切る線分のうち最も長い線分ＬがＷＣ粒子の外周両端部と交わる２点、すなわち２つの角部におけるそれぞれの曲率半径ｒを指し、超硬合金３１と３６におけるＷＣ粒子３２の角部の曲率半径を算出する際には、任意のＷＣ粒子５個の平均値で指す。 In addition, the curvature radius of the corner | angular part of the WC particle | grains 32 in the cemented carbides 31 and 36 in this invention is a cross section parallel to the surface by the side of the flank of the backing plates 4 and 24, or a flank as shown in FIG. In the scanning electron microscope observation of the cemented carbides 31 and 36 located at the two, the longest line segment L among the line segments crossing each WC particle 32 intersects with the two outer peripheral ends of the WC particle, that is, two corners When calculating the radius of curvature of the corners of the WC particles 32 in the cemented carbides 31 and 36, the average value of five arbitrary WC particles is used.

また、鉄族金属の好ましい含有量は、ｃＢＮ焼結体５の裏打板４においては１２〜２２面積％であり、ｃＢＮ複合焼結体２５の裏打板２４においては１８〜２８面積％である。 Further, the preferable content of the iron group metal is 12 to 22 area% in the backing plate 4 of the cBN sintered body 5 and 18 to 28 area% in the backing plate 24 of the cBN composite sintered body 25.

ここで、台金２は、丸いＷＣ粒子３４の比率が２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合している構成からなることが、台金２の塑性変形を抑制できるとともに、ロウ材７との密着力が高い点で望ましい。 Here, the base metal 2 has a configuration in which WC particles having a ratio of the round WC particles 34 of 20 area% or less are combined with 8 to 30 area% of the iron group metal, thereby suppressing plastic deformation of the base metal 2. In addition, it is desirable in that it has high adhesion to the brazing material 7.

また、ｃＢＮ複合焼結体２５は、図４（ａ）に示すような超高圧焼結体からなる繊維状の芯材５１単芯の周囲を硬質焼結体からなる被覆層５２にて結合した単芯繊維体５３ｓ、または図４（ｂ）に示すような超高圧焼結体からなる繊維状の芯材５１複数本の周囲を被覆層５２にて結合した多芯繊維体５３ｍを、例えば、図５（ａ）に示すように一方向に並べて整列させたものからなり、またそのシートを図５（ｂ）、（ｃ）に示すように複合繊維体５３の軸方向をシート間で任意の角度（例えば０°、４５°、９０°等）に変化させて積層することも可能である。さらに、図５（ｄ）のように、複合繊維体５３を断面方向にスライスしたものであってもよい。 In addition, the cBN composite sintered body 25 is obtained by bonding the periphery of a fiber core material 51 made of an ultrahigh pressure sintered body as shown in FIG. 4A with a coating layer 52 made of a hard sintered body. For example, a single-core fiber body 53s or a multi-core fiber body 53m in which a plurality of fibrous core materials 51 made of an ultrahigh-pressure sintered body as shown in FIG. As shown in FIG. 5 (a), the sheets are aligned in one direction, and the sheet is arranged in any axial direction between the sheets as shown in FIGS. 5 (b) and 5 (c). It is also possible to stack by changing the angle (eg, 0 °, 45 °, 90 °, etc.). Further, as shown in FIG. 5D, the composite fiber body 53 may be sliced in the cross-sectional direction.

繊維の配列方向は、図５（ａ）に示すように単層のシート状であってもよいが、単層のシートを厚み方向に複数層積層した多層の複合シートであることが超高圧複合焼結体１６中でより高い応力分散効果がある点で望ましい。また、本発明によれば、図５（ｃ）に示すように、多層シート状については、シート同士の向きが隣接するシート内の複合繊維体５３，５３の向きが異なるように積層することが望ましく、これによって切刃チップ２６の靭性をさらに高めることができる。繊維の配列方向のその他の例として、異方性をなくすために繊維体をランダムに混合して押し固めたランダムな配置であってもよい。 The arrangement direction of the fibers may be a single-layer sheet as shown in FIG. 5 (a), but it is an ultra-high pressure composite that is a multilayer composite sheet in which a plurality of single-layer sheets are laminated in the thickness direction. This is desirable in that there is a higher stress dispersion effect in the sintered body 16. Further, according to the present invention, as shown in FIG. 5 (c), in the multilayer sheet shape, the laminates may be laminated so that the directions of the composite fiber bodies 53, 53 in the adjacent sheets are different. Desirably, this can further enhance the toughness of the cutting edge tip 26. As another example of the arrangement direction of the fibers, a random arrangement in which fiber bodies are randomly mixed and consolidated in order to eliminate anisotropy may be used.

また、複合繊維体５３のサイズは、裏打板２４との密着性向上および工具２１としての耐欠損性を高めるために、芯材５１の直径が５〜３００μｍ、被覆層５２を含めた複合繊維体５３の１本の直径が６〜５００μｍであることが望ましい。 The size of the composite fiber body 53 is such that the core material 51 has a diameter of 5 to 300 μm and includes the covering layer 52 in order to improve the adhesion to the backing plate 24 and to improve the fracture resistance as the tool 21. It is desirable that the diameter of one of 53 is 6 to 500 μm.

本発明において、ｃＢＮ焼結体５またはｃＢＮ複合焼結体２５中のｃＢＮ焼結体は、立方晶窒化ホウ素（ｃＢＮ）を５０面積％以上含有してなり、コバルト（Ｃｏ）を必須として、所望によりニッケル（Ｎｉ）を含有せしめた結合金属にて結合させた超高圧材料からなる。なお、ｃＢＮ焼結体材料中に適宜周期表４、５および６族金属の炭化物、窒化物および炭窒化物の１種以上からなる硬質粒子を含有することが、ｃＢＮ焼結体の焼結性を改善できる点で望ましい。 In the present invention, the cBN sintered body in the cBN sintered body 5 or the cBN composite sintered body 25 contains 50% by area or more of cubic boron nitride (cBN), and contains cobalt (Co) as an essential component. It is made of an ultra-high pressure material bonded with a bonding metal containing nickel (Ni). It should be noted that the cBN sintered body preferably contains hard particles composed of one or more of carbides, nitrides, and carbonitrides of periodic table 4, 5 and 6 metals in the cBN sintered body material. It is desirable in that it can be improved.

一方、芯材５１の周囲に存在して芯材５１を結合する被覆層５２をなす硬質焼結体は、周期表４、５および６族金属の炭化物、窒化物および炭窒化物からなる群より選ばれる硬質粒子を結合金属にて結合した硬質焼結体または周期表４、５および６族金属、ＡｌおよびＳｉの酸化物、炭化物、窒化物、炭窒化物および硼化物からなる群より選ばれるセラミック粒子を焼結助剤にて結合したセラミックスにて構成される。 On the other hand, the hard sintered body that forms the coating layer 52 that exists around the core material 51 and bonds the core material 51 is made of a group consisting of carbides, nitrides, and carbonitrides of the periodic tables 4, 5 and 6 metals. Selected from the group consisting of a hard sintered body obtained by bonding selected hard particles with a bonding metal, or periodic table 4, 5 and 6 metals, Al and Si oxides, carbides, nitrides, carbonitrides and borides. It is composed of ceramics in which ceramic particles are bonded with a sintering aid.

具体的には、被覆層５２を構成する材質としては、周期表４、５および６族金属の炭化物、窒化物および炭窒化物の１種以上の硬質粒子として、特に炭化タングステン、炭化チタン、炭窒化チタン、窒化チタン、炭化タンタル、炭化ニオブ、炭化ジルコニウム、窒化ジルコニウム、炭化バナジウム、炭化クロムおよび炭化モリブデンの群から選ばれる少なくとも１種、さらには炭化タングステン、炭化チタンまたは炭窒化チタンの群から選ばれる少なくとも１種を５０〜９７面積％を、コバルトを必須として所望によりニッケルを含有せしめた結合金属３〜５０面積％にて結合してなる硬質焼結体が好適に使用可能である。 Specifically, the material constituting the coating layer 52 is one or more hard particles of carbides, nitrides, and carbonitrides of periodic table 4, 5 and 6 metals, particularly tungsten carbide, titanium carbide, and carbon. At least one selected from the group consisting of titanium nitride, titanium nitride, tantalum carbide, niobium carbide, zirconium carbide, zirconium nitride, vanadium carbide, chromium carbide and molybdenum carbide, and further selected from the group of tungsten carbide, titanium carbide or titanium carbonitride A hard sintered body obtained by bonding 50 to 97 area% of at least one selected from the above, and 3 to 50 area% of a bonding metal containing cobalt as an essential component and nickel as required is suitably used.

ここで、被覆層５２が超硬合金からなる場合、ｃＢＮ複合焼結体２５と裏打板２４との密着性がさらに高い点で望ましい。また、被覆層５２としては芯材とは異なる組成のｃＢＮ焼結体であってもよい。 Here, when the coating layer 52 consists of a cemented carbide, it is desirable at the point which the adhesiveness of the cBN compound sintered compact 25 and the backing plate 24 is still higher. The covering layer 52 may be a cBN sintered body having a composition different from that of the core material.

なお、本発明によれば、切削工具としてはソリッドタイプの工具であっても良いが、低コスト、製造の容易さ等の点で図１、２のようにスローアウェイ式の工具１，２１であることが望ましい。また、図１〜２では切削工具について例示したが、本発明はこれに限定されるものではなく、掘削工具や刃物等の他の工具への応用も可能である。 According to the present invention, the cutting tool may be a solid type tool, but in terms of low cost and ease of manufacture, the throwaway type tools 1 and 21 as shown in FIGS. It is desirable to be. 1 and 2 exemplify a cutting tool, the present invention is not limited to this, and application to other tools such as an excavation tool and a cutting tool is also possible.

（製造方法）
次に、本発明のロウ付けｃＢＮ工具の製造方法について説明する。 (Production method)
Next, the manufacturing method of the brazing cBN tool of this invention is demonstrated.

まず、超硬合金製の台金２および裏打板ロウ材側４ｂ、２４ｂを作製する。具体的には、平均粒径０．１〜１０μｍのＷＣ粉末と、平均粒径０．５〜１０μｍの少なくともＣｏを含有する鉄族金属粉末を５〜２０面積％、さらに必要に応じてＷ以外の周期表第４、５および６族金属の群から選ばれる少なくとも１種の炭化物、窒化物、炭窒化物を添加した混合粉末を調整する。次に、この混合粉末を所定の形状に成形し、１３５０〜１６００℃の温度域において０．５〜２時間焼成する。この際、窒化物およびまたは炭窒化物を添加して焼成の雰囲気を制御することもできる。その後、所望により研削加工を施して裏打板ロウ材側板状体４１を作製する。 First, the base metal 2 made of cemented carbide and the backing plate brazing material side 4b, 24b are prepared. Specifically, WC powder having an average particle diameter of 0.1 to 10 μm and iron group metal powder containing at least Co having an average particle diameter of 0.5 to 10 μm are contained in an amount of 5 to 20 area%, and if necessary, other than W A mixed powder to which at least one kind of carbide, nitride, and carbonitride selected from the group of metals of Group 4, 5 and 6 of the periodic table is added is prepared. Next, this mixed powder is formed into a predetermined shape and fired in a temperature range of 1350 to 1600 ° C. for 0.5 to 2 hours. At this time, the firing atmosphere can be controlled by adding nitride and / or carbonitride. Thereafter, grinding processing is performed as desired to produce the backing plate brazing material side plate-like body 41.

また、平均粒径０．１〜５μｍのＷＣ粉末を所定量と、平均粒径０．１〜３μｍのＣｏ粉末を７〜２０質量％との割合で調合、混合して、裏打板ｃＢＮ側用混合粉末４２を準備する。 Also, for the backing plate cBN side, a predetermined amount of WC powder having an average particle size of 0.1 to 5 μm and a Co powder having an average particle size of 0.1 to 3 μm are mixed and mixed at a ratio of 7 to 20% by mass. A mixed powder 42 is prepared.

一方、ｃＢＮ焼結体５を用いる場合には、ｃＢＮ焼結体５を作製するための原料粉末を混合し、所定の成形した図６（ａ）のｃＢＮ成形体４０を作製する。他方、ｃＢＮ複合焼結体２５を用いる場合には、以下の方法により図６（ｂ）のｃＢＮ複合成形体６１を作製する。図７、図８は、図４の複合繊維体５３の製造方法を説明するための工程図である。 On the other hand, when the cBN sintered body 5 is used, the raw material powder for producing the cBN sintered body 5 is mixed to produce a predetermined shaped cBN compact 40 of FIG. 6A. On the other hand, when the cBN composite sintered body 25 is used, the cBN composite molded body 61 shown in FIG. 6B is produced by the following method. 7 and 8 are process diagrams for explaining a method of manufacturing the composite fiber body 53 of FIG.

複合繊維体５３を作製するにあたり、まず、芯材用成形体５１ａを作製する。芯材用成形体５１ａを作製する方法は基本的には公知の粉末冶金法、つまり原料粉末と結合剤（バインダ）とを混合して成形する方法によって作製することができる。 In producing the composite fiber body 53, first, the core material molded body 51a is produced. The core material molded body 51a can be basically manufactured by a known powder metallurgy method, that is, a method in which raw material powder and a binder (binder) are mixed and molded.

具体的な方法として、まず、原料粉末として０．２〜３μｍの平均粒径を有するｃＢＮ原料粉末、平均粒径０．２〜３μｍの周期表第４、５および６族金属から選ばれる１種または２種以上の元素の炭化物粉末、窒化物粉末、および必要により平均粒径０．５〜５μｍのＡｌあるいは鉄族金属の内の少なくとも一種の原料粉末を特定の組成に秤量し粉砕混合する。この混合粉末を用いて芯材用成形体５１ａ形状に成形する。 As a specific method, first, a cBN raw material powder having an average particle size of 0.2 to 3 μm as a raw material powder, one selected from Group 4, 5 and 6 metals of the periodic table having an average particle size of 0.2 to 3 μm. Alternatively, carbide powder of two or more elements, nitride powder, and, if necessary, at least one raw material powder of Al or iron group metal having an average particle size of 0.5 to 5 μm is weighed to a specific composition and pulverized and mixed. Using this mixed powder, the core material is formed into a shape 51a.

一方、芯材用成形体５１ａとは異なる組成の被覆層をなす材料を前述したバインダとともに混錬してプレス成形、押出成形または鋳込み成形等の成形方法により半割円筒形状の２本の被覆層用成形体５２ａを作製し、この被覆層用成形体５２ａを芯材用成形体５１ａの外周を覆うように配置した成形体５３ａを作製する（図７（ｂ）および（ｃ）参照）。 On the other hand, two half-cylindrical coating layers are formed by kneading a material having a coating layer having a composition different from that of the core molding 51a together with the above-described binder by a molding method such as press molding, extrusion molding or casting. A molded body 52a is produced, and a molded body 53a is produced in which the covering layer molded body 52a is arranged so as to cover the outer periphery of the core material molded body 51a (see FIGS. 7B and 7C).

そして、押出機１００を用いて芯材用成形体５１ａと被覆層用成形体５２ａとからなる上記成形体５３ａを共押出成形することにより、芯材用成形体５１ａの周囲に被覆層用成形体５２ａが被覆され、細い径に伸延された図４（ａ）のシングルタイプの単芯繊維体５３ｓを作製することができる（図７（ｄ）参照）。 Then, by using the extruder 100 to co-extrusion the molded body 53a composed of the core body molded body 51a and the coating layer molded body 52a, the coated body molded body is formed around the core material molded body 51a. A single-type single-core fiber body 53s shown in FIG. 4A that is covered with 52a and extended to a thin diameter can be manufactured (see FIG. 7D).

また、複合繊維体５３の形成にあたり、図８に示すように、上記共押出した長尺状の単芯繊維体５３ｓを複数本集束した集束体５４を再度共押出成形することによって、図４（ｂ）に示すような繊維密度の高いマルチタイプの多芯繊維体５３ｍを作製することができる。なお、複合繊維体５３ｓ、５３ｍの断面は、円形のみならず、四角形、三角形でもよい。 Further, in forming the composite fiber body 53, as shown in FIG. 8, the bundling body 54 obtained by focusing a plurality of the coextruded long single-core fiber bodies 53s is again coextruded to form FIG. A multi-type multi-core fiber body 53m having a high fiber density as shown in b) can be produced. The cross sections of the composite fiber bodies 53s and 53m may be not only a circle but also a square or a triangle.

そして、図５（ａ）〜（ｃ）に示したように、この長尺状の複合繊維体５３を２列〜１００列に整列させて型内で加熱加圧して複合シート５５を得て、所望によりさらにこの複合シート５５の複数枚を、隣接する複合シート５５、５５の複合繊維体５３同士の向きが異なる角度となるように複合シート５５を厚み方向に複数枚積層して多層構造の複合構造成形体５６を得る。また、この複合構造体を必要に応じ、図５（ｄ）に示すように、複合繊維体５３の断面方向に切断することもできる。または、複合繊維体５３を整列させずにランダムに配列することも可能である。 And as shown to Fig.5 (a)-(c), this long composite fiber body 53 is aligned in 2 rows-100 rows, and it heat-presses in a type | mold, and obtained the composite sheet 55, If desired, a plurality of the composite sheets 55 may be laminated in the thickness direction so that the directions of the composite fiber bodies 53 of the adjacent composite sheets 55 and 55 are different from each other. A structural molded body 56 is obtained. Further, the composite structure can be cut in the cross-sectional direction of the composite fiber body 53 as shown in FIG. Alternatively, the composite fiber bodies 53 can be arranged randomly without being aligned.

次に、単層の複合シート５５、多層の複合構造成形体５６を超硬合金製の裏打板２４上に載置して、３００〜７００℃、１０〜２００時間で昇温または保持させて脱バインダ処理を行ってｃＢＮ複合焼結体用成形体６１を作製する。 Next, the single-layer composite sheet 55 and the multilayer composite structure formed body 56 are placed on the cemented carbide backing plate 24, and the temperature is increased or maintained at 300 to 700 ° C. for 10 to 200 hours. Binder processing is performed to produce a compact body 61 for a cBN composite sintered body.

そして、図６（ａ）（ｂ）に示すように、裏打板４、２４のロウ材７側となる上記板状の超硬合金の表面に、ｃＢＮ複合焼結体２５側を形成するための混合粉末をプレス成形によって敷き詰めて、さらに、ｃＢＮ成形体４０または脱バインダ処理したｃＢＮ複合焼結体用成形体６１（複合構造成形体５５、５６）を載置した状態で超高圧装置内にセットして加圧圧力４〜６ＧＰａ、温度１２００〜１６００℃、時間１０〜３０分で焼成して一体化することにより裏打板４、２４と接合一体化する。その後、これを、ワイヤ放電加工機、切削、研磨等で切刃チップ形状に加工して切刃チップ６、２６を得る。 Then, as shown in FIGS. 6A and 6B, the cBN composite sintered body 25 side is formed on the surface of the plate-shaped cemented carbide which is the brazing material 7 side of the backing plates 4 and 24. The mixed powder is spread by press molding, and further set in the ultrahigh pressure apparatus in a state where the cBN compact 40 or the binder-decomposed cBN composite sintered compact 61 (composite structure compacts 55, 56) is placed. Then, it is bonded and integrated with the backing plates 4 and 24 by baking and integrating them at a pressure of 4 to 6 GPa, a temperature of 1200 to 1600 ° C., and a time of 10 to 30 minutes. Thereafter, this is processed into a cutting edge tip shape by a wire electric discharge machine, cutting, polishing or the like to obtain cutting edge chips 6 and 26.

本発明によれば、裏打板ロウ材側４ｂ、２４ｂの超硬合金は無加圧状態で焼成されるためＷＣ粒子は粒成長によって角ばった形状となり、裏打板ｃＢＮ側４ａ、２４ａは超高圧状態で焼成されるためＷＣ粒子は角が丸い形状となる。 According to the present invention, the cemented carbide on the backing plate brazing material side 4b, 24b is fired in a non-pressurized state, so that the WC particles have an angular shape due to grain growth, and the backing plate cBN side 4a, 24a is in an ultra high pressure state. The WC particles are rounded at the corners.

さらに、裏打板４、２４と上記ｃＢＮ焼結体５またはｃＢＮ複合焼結体２５とが一体化された切刃チップ６、２６を、台金２の角部に形成された取付座３に銀ロウ７などを用いてロウ付け接合する。また、所望により、得られた工具に対してＣＶＤ法やＰＶＤ法によって工具１、２１の表面にコーティング層を形成してもよい。 Further, the cutting edge tips 6 and 26 in which the backing plates 4 and 24 and the cBN sintered body 5 or the cBN composite sintered body 25 are integrated are attached to the mounting seat 3 formed at the corner of the base metal 2 with silver. Brazing and joining is performed using brazing 7 or the like. If desired, a coating layer may be formed on the surfaces of the tools 1 and 21 by CVD or PVD with respect to the obtained tool.

以下、実施例を挙げて本発明を詳細に説明するが、本発明は以下の実施例のみに限定されるものではない。 EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.

裏打板のロウ材側をなす超硬合金を作製するために、ＷＣ原料粉末と、平均粒径０．８μｍの金属Ｃｏ原料粉末と、平均粒径１．５μｍのＣｒ_３Ｃ_２粉末、ＶＣ粉末、ＴｉＣ粉末、ＴａＣ粉末を用いて表１に示す比率となるように調合・成形し、表１に示す条件で焼成した。そして、得られた超硬合金を片面のみ研削加工し、厚み３ｍｍの板状体とした。また、表１に示すｃＢＮ焼結体側の裏打板を作製するために、ＷＣ原料粉末と、平均粒径０．８μｍの金属Ｃｏ原料粉末と、平均粒径１．５μｍのＣｒ_３Ｃ_２粉末、ＶＣ粉末、ＴｉＣ粉末、ＴａＣ粉末を用いて表１に示す割合の混合粉末を調整した。なお、ＷＣ原料粉末の平均粒径は後述する超高圧焼成後の裏打板が表１に示す平均粒径となるように調整した。 In order to produce a cemented carbide forming the brazing material side of the backing plate, a WC raw material powder, a metallic Co raw material powder having an average particle size of 0.8 μm, a Cr ₃ C ₂ powder having an average particle size of 1.5 μm, and a VC powder , TiC powder and TaC powder were prepared and molded so as to have the ratio shown in Table 1, and fired under the conditions shown in Table 1. Then, the obtained cemented carbide was ground on only one side to obtain a plate-like body having a thickness of 3 mm. Moreover, in order to produce the backing plate on the cBN sintered body side shown in Table 1, a WC raw material powder, a metal Co raw material powder having an average particle size of 0.8 μm, a Cr ₃ C ₂ powder having an average particle size of 1.5 μm, The mixed powder of the ratio shown in Table 1 was adjusted using VC powder, TiC powder, and TaC powder. The average particle size of the WC raw material powder was adjusted so that the backing plate after the ultra-high pressure firing described later has the average particle size shown in Table 1.

また、平均粒径０．５μｍのｃＢＮ原料粉末、平均粒径１．０μｍのＴｉＣ原料粉末、平均粒径１．０μｍのＴｉＮ原料粉末、平均粒径１．５μｍの金属Ａｌ原料粉末を用いて、焼結体の組成が表１に示す組成となるように調合し、この粉体を、アルミナ製ボールを用いてボールミルで１５時間混合した。この混合した粉体を圧力９８ＭＰａでプレス成形してｃＢＮ成形体を作製した。

Also, using a cBN raw material powder having an average particle size of 0.5 μm, a TiC raw material powder having an average particle size of 1.0 μm, a TiN raw material powder having an average particle size of 1.0 μm, and a metal Al raw material powder having an average particle size of 1.5 μm, The composition of the sintered body was prepared so as to have the composition shown in Table 1, and this powder was mixed for 15 hours with a ball mill using alumina balls. The mixed powder was press-molded at a pressure of 98 MPa to prepare a cBN compact.

そして、上記超硬合金製の板状体を超高圧焼成用の冶具であるＭｏ製のカプセル中に挿入した状態で、超硬合金製の板状体の表面にｃＢＮ焼結体側の裏打板用の混合粉末を敷き詰め、プレス成形機を用いて０．０５ＭＰａ程度の低圧で混合粉末を加圧することによって混合粉末を平坦に均し、その上に上記ｃＢＮ成形体を載置した。 Then, in the state where the cemented carbide plate is inserted into a Mo capsule which is a jig for ultra-high pressure firing, the cBN sintered body side backing plate is placed on the surface of the cemented carbide plate. Then, the mixed powder was flattened by pressurizing the mixed powder at a low pressure of about 0.05 MPa using a press molding machine, and the cBN compact was placed thereon.

そして、このカプセルを超高圧焼成装置に配置し、５．５ＧＰａ、１４５０℃で２０分焼成し、ｃＢＮ焼結体と裏打板が一体化した焼結体を作製した。その後、この構造体の上下面のカプセルを研削除去し、さらに、作製したｃＢＮ焼結体に対してワイヤ放電加工によって所定の寸法に切り出し、図１に示されるようなＣＮＧＡ１２０４０８の形状の表３に示す超硬合金からなる台金の切り込み段部である取付座に銀ロウにてロウ付けを行ってスローアウェイチップ型の切削工具を作製した。そして、この切削工具の切刃に対してダイヤモンドホイールを用いて刃先処理（チャンファホーニング）を施した。 And this capsule was arrange | positioned to an ultrahigh pressure baking apparatus, and it baked at 5.5 GPa and 1450 degreeC for 20 minutes, and produced the sintered compact with which the cBN sintered compact and the backing plate were integrated. Thereafter, the capsules on the upper and lower surfaces of this structure are ground and removed. Further, the produced cBN sintered body is cut into a predetermined size by wire electric discharge machining, and the shape of CNGA120408 as shown in FIG. A throw-away tip type cutting tool was produced by brazing a mounting seat, which is a cut-in step portion of a base metal made of cemented carbide, with a silver solder. Then, the cutting edge of the cutting tool was subjected to blade edge processing (changing honing) using a diamond wheel.

得られた切削工具の断面を走査型電子顕微鏡にて５０００倍の倍率で観察し、裏打板のｃＢＮ側とロウ材側それぞれの組織について、ＷＣ粒子の面積比率、曲率半径ｒが０．１μｍ以上であるＷＣ粒子の面積比率、結合相の面積比率を画像解析装置によって測定した。結果は表２に示した。また、得られた切削工具を用いて以下の切削条件にて切削試験を行った。結果は表３に示した。 The cross section of the obtained cutting tool was observed with a scanning electron microscope at a magnification of 5000 times, and the area ratio of WC particles and the radius of curvature r were 0.1 μm or more for the structures on the cBN side and brazing material side of the backing plate. The area ratio of the WC particles and the area ratio of the binder phase were measured by an image analyzer. The results are shown in Table 2. Moreover, the cutting test was done on the following cutting conditions using the obtained cutting tool. The results are shown in Table 3.

（切削条件）
切削方法：軽断続端面加工
被削材：ＳＣＭ４３５（浸炭焼入鋼：ＨＲＣ５８〜６２）、３個穴付き
切削速度：１５０ｍ／ｍｉｎ
送り：０．１５ｍｍ／ｒｅｖ
切り込み：肩切り込み０．２ｍｍ、深さ切り込み０．４ｍｍ
切削状態：乾式
評価方法：欠損するまで加工を実施し、欠損までの衝撃回数により優劣を判断した。また、衝撃回数３００回毎にチッピングなどの有無を顕微鏡にて確認した。

(Cutting conditions)
Cutting method: Light interrupted end face processed work material: SCM435 (carburized and hardened steel: HRC58-62), cutting speed with 3 holes: 150 m / min
Feeding: 0.15mm / rev
Cut: Shoulder cut 0.2mm, depth cut 0.4mm
Cutting state: Dry evaluation method: Processing was carried out until the chip was damaged, and the superiority or inferiority was judged by the number of impacts until the chip was broken. Further, the presence or absence of chipping or the like was confirmed with a microscope every 300 shocks.

表１〜３より、裏打板として裏打板ロウ材側板状体のみを用い、裏打板全体の超硬合金において、丸いＷＣ粒子の比率５０面積％未満となった試料Ｎｏ．１２では、裏打板とｃＢＮ焼結体との界面にクラックが発生して早期に欠損した。また、試料Ｎｏ．１１は超高圧焼成条件によって裏打板ｃＢＮ側の超硬合金が過焼結になってしまい、裏打板ｃＢＮ側の超硬合金における丸いＷＣ粒子の比率が５０面積％未満となったが、これも裏打板とｃＢＮ焼結体との界面にクラックが発生して早期に欠損した。さらに、裏打板として裏打板ｃＢＮ側用混合粉末のみを用い、裏打板ロウ材側の超硬合金において、角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％より多い試料Ｎｏ．１３では、超高圧焼成時に裏打板が変形してしまい切削試験においてもクラックが発生して早期に欠損した。また、鉄族金属量が１２面積％より少ない試料Ｎｏ．９では、切削時に裏打板とｃＢＮ焼結体との界面にクラックが発生して早期に欠損した。さらに、鉄族金属量が３０面積％より多い試料Ｎｏ．１０では、cＢＮ焼結体との熱膨張係数差が大きくなり、ロウ付け時にマイクロクラックが発生して、そのクラックをもとに早期に欠損した。 From Tables 1 to 3, only the backing plate brazing material side plate was used as the backing plate, and in the cemented carbide of the entire backing plate, the sample No. 1 was less than 50 area% of the round WC particles. In No. 12, cracks occurred at the interface between the backing plate and the cBN sintered body, resulting in early chipping. Sample No. In No. 11, the cemented carbide on the backing plate cBN side was oversintered due to the ultra-high pressure firing conditions, and the ratio of round WC particles in the cemented carbide on the backing plate cBN side was less than 50 area%. Cracks occurred at the interface between the backing plate and the cBN sintered body and were lost early. Further, only the mixed powder for the backing plate cBN side is used as the backing plate, and in the cemented carbide on the backing plate brazing material side, the WC particles having a corner radius of curvature of 0.1 μm or more are more than 20 area% of the total WC particles. Sample No. In No. 13, the backing plate was deformed at the time of ultra-high pressure firing, and cracks occurred in the cutting test, resulting in early chipping. In addition, Sample No. with an iron group metal content of less than 12 area%. In No. 9, cracks occurred at the interface between the backing plate and the cBN sintered body at the time of cutting, resulting in early chipping. Furthermore, Sample No. with an amount of iron group metal greater than 30 area%. In No. 10, the difference in thermal expansion coefficient from the cBN sintered body was increased, microcracks were generated during brazing, and the chip was lost early based on the cracks.

これに対して、本発明の範囲内である試料Ｎｏ．１〜６は、いずれも工具寿命が長いものであった。 On the other hand, sample No. which is within the scope of the present invention. 1 to 6 all had a long tool life.

実施例２
実施例１のｃＢＮ焼結体に代えて次のｃＢＮ複合焼結体を作製した。実施例１で用いた原料粉末を用いて焼結体中の芯材と被覆層の組成が表４となるように粉末を調合し、これに有機バインダとしてセルロース、ポリエチレングリコールを、溶剤としてポリビニルアルコールを総量で１００体積部加えて混錬して、実施例１と同じ形状の芯材用成形体と被覆層用成形体を作製し、芯材用成形体の外周を被覆層用成形体が覆うように配置して複合繊維体を作製した。 Example 2
The following cBN composite sintered body was produced instead of the cBN sintered body of Example 1. Using the raw material powder used in Example 1, a powder was prepared so that the composition of the core material and the coating layer in the sintered body was as shown in Table 4, and cellulose and polyethylene glycol were used as an organic binder, and polyvinyl alcohol was used as a solvent. 100 parts by volume in total is added and kneaded to produce a core material molded body and a coating layer molded body having the same shape as in Example 1, and the outer periphery of the core material molded body covers the outer periphery of the core layer molded body. Thus, a composite fiber body was produced.

次に、上記複合繊維体を共押出して直径が１ｍｍの伸延された単芯繊維成形体を作製した後、この伸延された複合成形体１００本を集束して再度共押出成形し、直径が１ｍｍのマルチフィラメント構造の多芯繊維成形体を作製した。さらに、上記マルチフィラメント構造の複合繊維体を１００ｍｍの長さにカットし、並列に整列させてシート状とし、この複合シート３枚を図５（ｃ）のように積層して積層体を作製した。また、この積層体を３００〜７００℃まで１００時間で昇温することによって脱バインダ処理を行い、ｃＢＮ複合成形体（複合構造成形体５６）とした（試料Ｎｏ．１４〜２０）。 Next, the composite fiber body is coextruded to produce an elongated single-core fiber molded body having a diameter of 1 mm, and then 100 of the stretched composite molded bodies are converged and coextruded again to obtain a diameter of 1 mm. A multifilament fiber molded body having a multifilament structure was prepared. Furthermore, the composite fiber body having the multifilament structure was cut to a length of 100 mm and aligned in parallel to form a sheet, and the three composite sheets were laminated as shown in FIG. 5C to produce a laminate. . Further, the binder was subjected to binder removal treatment by raising the temperature of the laminate to 300 to 700 ° C. over 100 hours to obtain a cBN composite molded body (composite structure molded body 56) (Sample Nos. 14 to 20).

そして、このｃＢＮ複合成形体を用いて実施例１の試料Ｎｏ．６の裏打板ロウ材側用の超硬合金と表４の裏打板ｃＢＮ側用の超硬合金原料粉末を用いて実施例１と同様に超高圧焼結を行い、試料Ｎｏ．６の台金にロウ付けした後、研削加工を施してｃＢＮ複合焼結体を作製し、実施例１と同じ条件で切削評価を行った。結果は表５に示した。

And using this cBN composite molded body, the sample No. 1 of Example 1 was used. Using the cemented carbide for the backing plate brazing material side of No. 6 and the cemented carbide raw material powder for the backing plate cBN side of Table 4, ultra high pressure sintering was performed in the same manner as in Example 1, and sample No. After brazing the base metal of No. 6, a cBN composite sintered body was produced by grinding, and cutting evaluation was performed under the same conditions as in Example 1. The results are shown in Table 5.

表４、５の結果から明らかなとおり、裏打板として裏打板ロウ材側板状体のみを用い、裏打板ｃＢＮ側の超硬合金において、丸いＷＣ粒子の比率５０面積％未満となった試料Ｎｏ．２０では、裏打板とｃＢＮ焼結体との界面にクラックが発生して早期に欠損した。また、裏打板として裏打板ｃＢＮ側用混合粉末のみを用い、裏打板ロウ材側の超硬合金において、角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％より多い試料Ｎｏ．１９では、超高圧焼成時に裏打板が変形してしまい切削試験においてもクラックが発生して早期に欠損した。さらに、鉄族金属量が１２面積％より少ない試料Ｎｏ．１８では、切削時に裏打板とｃＢＮ焼結体との界面にクラックが発生して早期に欠損した。 As is apparent from the results of Tables 4 and 5, only the backing plate brazing material side plate-like body was used as the backing plate, and in the cemented carbide on the backing plate cBN side, the ratio of the round WC particles was less than 50 area%. In No. 20, cracks occurred at the interface between the backing plate and the cBN sintered body, resulting in early chipping. Further, only the mixed powder for the backing plate cBN side is used as the backing plate, and in the cemented carbide on the backing plate brazing material side, the WC particles having a corner radius of curvature of 0.1 μm or more are more than 20 area% of the total WC particles. Sample No. In No. 19, the backing plate was deformed at the time of ultra-high pressure firing, and cracks were generated in the cutting test, resulting in early chipping. Furthermore, the sample No. 1 with less iron group metal content than 12 area%. In No. 18, cracks occurred at the interface between the backing plate and the cBN sintered body at the time of cutting, resulting in early chipping.

これに対して、本発明の範囲内である試料Ｎｏ．１４〜１７は、いずれも工具寿命が長いものであった。 On the other hand, sample No. which is within the scope of the present invention. 14 to 17 all had a long tool life.

本発明のロウ付けｃＢＮ工具の一実施態様を示す（ａ）斜視図、（ｂ）切刃チップ付近の部分断面図である。It is (a) perspective view which shows one embodiment of the brazing cBN tool of this invention, (b) It is a fragmentary sectional view of cutting blade tip vicinity. 本発明のロウ付けｃＢＮ工具の他の実施態様を示す（ａ）斜視図、（ｂ）切刃チップ付近の部分断面図である。It is the (a) perspective view which shows other embodiments of the brazing cBN tool of the present invention, and (b) the fragmentary sectional view near the cutting edge tip. 図１、２の裏打板を構成する超硬合金について、（ａ）ｃＢＮ側、（ｂ）ロウ材側の組織を説明するための模式図である。It is a schematic diagram for demonstrating the structure of (a) cBN side and (b) brazing material side about the cemented carbide which comprises the backing plate of FIGS. 図２のｃＢＮ複合焼結体を構成する複合繊維体の構造を示し、（ａ）シングル構造の単芯繊維体、（ｂ）マルチフィラメント構造の多芯繊維体の一例を示す概略斜視図である。It is a schematic perspective view which shows the structure of the composite fiber body which comprises the cBN composite sintered compact of FIG. 2, and shows an example of (a) single core fiber body of a single structure, (b) multicore fiber body of a multifilament structure. . （ａ）〜（ｄ）は、本発明にかかる超高圧（複合）構造焼結体中の複合繊維体の配置方法を説明するための図である。(A)-(d) is a figure for demonstrating the arrangement | positioning method of the composite fiber body in the ultra-high pressure (composite) structure sintered compact concerning this invention. ｃＢＮ焼結体を超高圧焼成する際の成形体の配置状態を説明するための図である。It is a figure for demonstrating the arrangement | positioning state of the molded object at the time of baking a cBN sintered compact by ultra-high pressure. （ａ）〜（ｄ）は、本発明にかかる超高圧複合焼結構造体について、シングルタイプの単芯繊維成形体の製造方法を示す工程図である。(A)-(d) is process drawing which shows the manufacturing method of a single type single core fiber molded object about the ultra-high pressure compound sintered structure concerning this invention. 本発明にかかる超高圧複合焼結構造体について、マルチタイプの多芯繊維成形体の製造方法を示す工程図である。It is process drawing which shows the manufacturing method of a multi-type multi-core fiber molded object about the ultra-high pressure compound sintered structure concerning this invention.

符号の説明Explanation of symbols

１、２１切削工具
２台金
３取り付け座
４、２４裏打板
５ｃＢＮ焼結体
２５ｃＢＮ複合焼結体
６、２６切刃チップ
７ロウ材
８、２８すくい面
９、２９逃げ面
１０、３０切刃
１１、３１取付孔
４０ｃＢＮ成形体
４１裏打板ロウ材側板状体
４２裏打板ｃＢＮ側用混合粉末
５１芯材
５１ａ芯材用成形体
５２被覆層
５２ａ被覆層用成形体
５３複合繊維体
５３ａ成形体
５３ｓシングル構造単芯繊維体
５３ｍマルチフィラメント構造多芯繊維体
５５複合シート
５６複合構造成形体
６１ｃＢＮ複合焼結体用成形体 1, 21 Cutting tool 2 Base 3 Mounting seat 4, 24 Back plate 5 cBN sintered body 25 cBN composite sintered body 6, 26 Cutting edge tip 7 Brazing material 8, 28 Rake face 9, 29 Relief face 10, 30 Cutting Blades 11 and 31 Mounting hole 40 cBN molded body 41 Back plate brazing material side plate 42 Mixed powder 51 for backing plate cBN side Core material 51a Core material molded body 52 Coating layer 52a Coating layer molded body 53 Composite fiber body 53a Molding Body 53s Single structure single core fiber body 53m Multifilament structure multicore fiber body 55 Composite sheet 56 Composite structure molded body 61 Molded body for cBN composite sintered body

Claims

切刃を有するｃＢＮ焼結体の下面に接合した裏打板を超硬合金製の台金の所定位置にロウ付け接合したロウ付けｃＢＮ工具において、前記裏打板の前記ｃＢＮ焼結体側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の５０面積％以上を含むＷＣ粒子を鉄族金属１２〜３０面積％で結合した超硬合金からなり、該裏打板の前記ロウ材側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合した超硬合金からなることを特徴とするロウ付けｃＢＮ工具。 In a brazed cBN tool in which a backing plate joined to the lower surface of a cBN sintered body having a cutting edge is brazed and joined to a predetermined position of a cemented carbide base metal, the cBN sintered body side of the backing plate has corner portions. A WC particle having a curvature radius of 0.1 μm or more is made of a cemented carbide in which WC particles including 50% by area or more of all WC particles are combined with 12 to 30% by iron group metal, and the brazing material side of the backing plate is Brazing cBN characterized in that WC particles having a corner radius of curvature of 0.1 μm or more are made of cemented carbide in which WC particles of 20% by area or less of all WC particles are bonded with 8 to 30% by area of iron group metal. tool.

切刃を有するｃＢＮ焼結体からなる繊維状の芯材の周囲を硬質焼結体にて結合したｃＢＮ複合焼結体の下面に接合した裏打板を超硬合金製の台金の所定位置にロウ付け接合したロウ付けｃＢＮ工具において、前記裏打板の前記ｃＢＮ複合焼結体側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の５０面積％以上を含むＷＣ粒子を鉄族金属１２〜３０面積％で結合した超硬合金からなり、該裏打板の前記ロウ材側は角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合した超硬合金からなることを特徴とするロウ付けｃＢＮ工具。 A backing plate bonded to the lower surface of a cBN composite sintered body in which the periphery of a fibrous core material made of a cBN sintered body having a cutting edge is bonded with a hard sintered body is placed at a predetermined position of a cemented carbide base metal. In the brazed cBN tool that is brazed and joined, the cBN composite sintered body side of the backing plate includes WC particles in which the WC particles having a corner radius of curvature of 0.1 μm or more include 50 area% or more of the total WC particles. The brazing material side of the backing plate is made of cemented carbide bonded with 12 to 30 area% of metal, and WC particles having a corner radius of curvature of 0.1 μm or more are WC particles of 20 area% or less of all WC particles. A brazing cBN tool comprising a cemented carbide bonded with 8 to 30 area% of an iron group metal.

前記台金が、角部の曲率半径が０．１μｍ以上のＷＣ粒子が全ＷＣ粒子の２０面積％以下のＷＣ粒子を鉄族金属８〜３０面積％で結合している超硬合金からなることを特徴とする請求項１または２記載のロウ付けｃＢＮ工具。 The base metal is made of a cemented carbide in which WC particles having a corner radius of curvature of 0.1 μm or more are bonded with WC particles of 20% by area or less of all WC particles by 8 to 30% by iron group metal. The brazed cBN tool according to claim 1 or 2.