摘要:
A cBN sintered body superior in chipping resistance. The cBN sintered body is a sintered body in which cBN particles are bonded through a bonding phase. The bonding phase has a two-dimensionally continuous structure. The bonding phase comprises at least one kind selected from the group consisting of (a) carbide, nitride, carbonitride, or boride of a 4a-, 5a-, or 6a-group transition metal in the periodic table; (b) nitride, boride, or oxide of Al; (c) at least one kind of carbide, nitride, carbonitride, and boride of Fe, Co, or Ni; and (d) a mutual solid solution of those. The percentage of cBN content is 45 to 70% in volume. The bonding phase has the thickness of which the average value is 1.5 &mgr;m or less and the standard deviation is 0.9 &mgr;m or less with the cBN particles having an average particle size of 2 to 6 &mgr;m inclusive. The bonding phase has the thickness of which the average value is 1.0 &mgr;m or less and the standard deviation is 0.7 &mgr;m or less with the cBN particles having an average particle size of not less than 0.01 &mgr;m and less than 2.0 &mgr;m.
摘要:
A high-pressure phase boron nitride-based high-hardness high-strength sintered body for cutting tools represented by a milling tool and an end mill etc., which is improved in wear resistance and chipping resistance, is obtained. The high-pressure phase boron nitride-based sintered body according to the present invention comprises a plurality of grains (1) of high-pressure phase boron nitride and a binder phase (2, 3), and the content of the aforementioned grains (1) is at least 20.0 volume % and not more than 99.7 volume %. The aforementioned binder phase (2, 3) includes a first binder phase (2) enclosing the aforementioned grains (1) and a second binder phase (3) other than that. The first binder phase (2) consists of the form of at least either a nitride of at least one of Ti, TiAl, Zr and Hf or a solid solution thereof. The aforementioned second binder phase (3) includes a grain growth suppressive binder phase (4) between a plurality of the aforementioned grains (1) enclosed with the aforementioned first binder phase (2).
摘要:
A sintered body consists of high-pressure phase boron nitride, a residual binder phase and an unavoidable impurity, and contains high-pressure phase boron nitride powder which is previously coated with a binder before sintering. The coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and has an average thickness of 5 to 300 nm. Binder powder other than the coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and a contact ratio of high-pressure phase boron nitride particles in surface-to-surface contact with each other is at least 20% and less than 50%. The resulting high-pressure phase boron nitride-based hard and tough sintered body for a cutting tool is improved in wear resistance and chipping resistance.
摘要:
A sintered body contains a high pressure form boron nitride in the range of 20 to 70% by volume, a first binding material surrounding the high pressure form boron nitride with a thickness in the range of 5 nm to 300 nm and a second binding material of the balance. The first binding material is composed of at least one of nitride and boride of Ti and Al. The second binding material is composed of at least one selected from the group consisting of nitride, carbide, carbonitride, boride and oxide of Al and transition metals belonging to the group 4a, 5a and 6a in the periodic table and mutual solid solution thereof. Supposing that X is the amount of Al contained per unit volume in the first binding material and Y is the amount of Al contained per unit volume in the second binding material, the ratio X/Y is not less than 1.
摘要:
A sintered material containing high-pressure phase-type boron nitride and a binder is provided. The high-pressure phase-type boron nitride is contained in an amount of from 50% to 78% by volume, and the balance is a binder phase. The binder phase comprises at least one selected from the group consisting of nitride, carbide, carbonitride, and boride of Ti, nitride, boride and oxide of Al, carbide and boride of W, nitride, carbide, carbonitride and boride of Co, and carbide and boride of Ni, or a mutual solid solution thereof. The binder phase forms a binder phase which is continuous in a sintered material texture. The weight of metal components Al, W, Co and Ni which are present as compounds in the sintered material is from 3% to 20% based on the sintered material. The sintered material is excellent in crater resistance and capable of realizing a long tool life, even under the condition that the temperature of the cutting edge becomes high and the impact is large, as in high-speed interrupted cutting of hardened steel where the cutting speed V becomes at least 150 m/min.
摘要:
In a pilot hole of a workpiece made of a difficult-to-cut cast iron, a cutting tool having a leading end to which a cutting insert is attached is inserted to cut the surface of the wall of the pilot hole. At this time, the cutting tool rotates about an axis (α) and also revolves about another axis (β), so that contouring is performed on the workpiece by the tool. The cutting insert is formed of a sintered body having a CBN content of not less than 85% by volume, and the cutting insert has a thermal conductivity of not less than 100 W/(mK).
摘要:
A surface-covered CBN sintered body tool includes a base material formed with a cubic boron nitride (CBN) sintered body and a surface covering film covering a surface of the base material, and has a nega-land exposing the CBN sintered body in at least a portion thereof and a flank having the surface covering film formed thereon. With this, the surface-covered CBN sintered body tool having high defect resistance and wear resistance can be provided. The surface covering film preferably includes a nitride or a carbonitride of a compound including at least one element selected from the group consisting of Ti, Cr, Zr, and V and at least one element selected from the group consisting of Al, Si and B, or a nitride or a carbonitride of Ti.
摘要:
It is an object to provide a cutting tool which can perform high-quality, high-efficiency machining of a workpiece such as hardened steel.The cutting tool includes a finishing cutting edge 6 which initially cuts into the workpiece, and superfinishing cutting edges 7 for finishing the workpiece cut by the finishing cutting edge. The superfinishing cutting edges 7 project from the finishing cutting edge by a predetermined amount B in such a direction that the depth of cut of the superfinishing cutting edges increases. Each superfinishing cutting edge includes a burnishing portion 7a having a predetermined width L in the feed direction of the tool, and a wiper portion 7b. The superfinishing cutting edges 7 burnish the finished surface formed by the finishing cutting edge, while removing a affected layer formed by the finishing cutting edge.
摘要:
A composite sintered body according to the present invention contains at least cubic boron nitride and a binder. Cubic boron nitride has a continuous skeleton structure as a result of bonding of a plurality of first cubic boron nitride particles to each other. The binder has a continuous structure as a result of bonding of a plurality of binder particles to each other, that are present in a region except for a bonding interface where the first cubic boron nitride particles are bonded to each other. Second cubic boron nitride particles isolated from the first cubic boron nitride particles forming the skeleton structure are dispersed in the continuous structure of the binder particles.
摘要:
The present invention provides a cubic boron nitride sintered body, which achieves both of superior chipping resistance and wear resistance.In accordance with a first aspect of the present invention, a cubic boron nitride (cBN) sintered body contains cubic boron nitride particles and a bonding material used for bonding the cBN particles to one another. This sintered body is constituted by cBN particles in a range from 70 vol % to 98 vol % and a residual bonding material made from a Co compound, an Al compound and WC and a solid solution of these. Moreover, the cBN particles in the sintered body contain 0.03 wt % or less of Mg and 0.001 wt % or more to 0.05 wt % or less of Li.In accordance with a second aspect of the present invention, the cubic boron nitride sintered body has a composition in which the bonding material of the first aspect is changed to an Al compound.