Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
  • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
  • G01M11/30—Testing of optical devices, constituted by fibre optics or optical waveguides
  • G01M11/37—Testing of optical devices, constituted by fibre optics or optical waveguides in which light is projected perpendicularly to the axis of the fibre or waveguide for monitoring a section thereof
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/255—Splicing of light guides, e.g. by fusion or bonding
  • G02B6/2551—Splicing of light guides, e.g. by fusion or bonding using thermal methods, e.g. fusion welding by arc discharge, laser beam, plasma torch

Definitions

• the present invention relates to coated cemented carbide bodies particularly useful in tools for turning, milling and drilling of steels and stainless steels.
• Cemented carbide bodies are manufactured according to powder metallurgical methods including milling, pressing and sintering.
• the milling operation is an intensive mechanical milling in mills of different sizes and with the aid of milling bodies.
• the milling time is of the order of several hours up to days. Such processing is believed to be necessary in order to obtain a uniform distribution of the binder phase in the milled mixture, but it results in a wide WC grain size distribution.
• It is an aspect of this invention to provide a method of making a cemented carbide body comprising wet mixing without milling of at least two different WC-powders with deagglomerated powders of other carbides, binder metal and pressing agent such that the WC-powders are coated with the binder phase, said WC-grains being carefully deagglomerated before and after being coated with binder metal, the grains of the WC-powder being classified in at least two groups in which a group of smaller grains has a maximum grain size a max and a group of a larger grains has a minimum grain size b min , each group containing at least 10% of the total amount of WC grains wherein b min ⁇ a max >0.5 mm, the variation in grain size within each group being >1 ⁇ m, drying said mixture, pressing to a desired shape and sintering said pressed bodies.
• the present invention relates generally to a cemented carbide body comprising WC with an average grain size of ⁇ 10 ⁇ m in a binder phase.
• the WC grains are classified in at least two groups in which a group of smaller grains has a maximum grain size a max and a group of larger grains has a minimum grain size b min .
• Each group contains at least 10% of the total amount of WC grains.
• the cemented carbide body according to the invention is characterized in that b min ⁇ a max >0.5 ⁇ m and that the variation in grain size within each group is >1 ⁇ m.
• the WC grains have a narrow bimodal grain size distribution with grain sizes in the ranges 0-1.5 ⁇ m and 2.5-6.0 ⁇ m respectively, and with a weight ratio of fine WC particles (0-1.5 ⁇ m) to coarse WC particles (2.5-6.0 ⁇ m) in the range of 0.25-4.0, preferably 0.5-2.0.
• the amount of W dissolved in the binder phase is controlled by adjustment of the carbon content by small additions of carbon black or pure tungsten powder.
• the CW-value in inserts according to the invention shall be 0.82-1.0, preferably 0.86-0.96.
• a cemented carbide body comprising wet mixing without milling of at least two different WC-powders with deagglomerated powders of other carbides, generally TiC, TaC and/or NbC, binder metal and pressing agent, dried preferably by spray drying, pressed to inserts and sintered.
• the grains of the WC-powder are classified in at least two groups in which a group of smaller grains has a maximum grain size a max and a group of larger grains has a minimum grain size b min each group containing at least 10% of the total amount of WC grains wherein b min ⁇ a max >0.5 ⁇ m and the variation in grain size within each group is >1 ⁇ m.
• the WC grains are carefully deagglomerated before and after being coated with binder metal.
• WC-powders with two narrow grain size distributions of 0-1.5 ⁇ m and 2.5-6.0 ⁇ m respectively and a weight ratio of fine WC particles (0-1.5 ⁇ m) to coarse WC particles (2.5-6.0 ⁇ m) in the range of 0.25-4.0, preferably 0.5-2.0 are wet mixed without milling with other carbides generally TiC, TaC and/or NbC, binder metal and pressing agent, dried preferably by spray drying, pressed to inserts and sintered.
• Cemented carbide tool inserts of the type SEMN 1204 AZ, an insert for milling, with the composition in addition to WC of 8.4 wt % Co, 1.13 wt % TaC and 0.38 wt % NbC were produced according to the invention.
• Cobalt coated WC, WC-6 wt-% Co, prepared in accordance with U.S. Pat. No. 5,505,902 was carefully deagglomerated in a laboratory jetmill equipment, mixed with additional amounts of Co and deagglomerated uncoated (Ta,Nb)C and TaC powders to obtain the desired material composition.
• the coated WC-particles consisted of 50 wt % with an average grain size of 3.5 ⁇ m and 50 wt % with 1.2 ⁇ m average grain size, giving a bimodal grain size distribution.
• the mixing was carried out in an ethanol and water solution (0.25 l fluid per kg cemented carbide powder) for 2 hours in a laboratory mixer and the batch size was 10 kg. Furthermore, 2 weight-% lubricant, was added to the slurry.
• the carbon content was adjusted with carbon black to a binder phase alloyed with W corresponding to a CW-ratio of 0.89. After spray drying, the inserts were pressed and sintered according to standard practise and dense structures with no porosity were obtained.
• the inserts were coated with a 0.5 ⁇ m equiaxed TiCN-layer (with a high nitrogen content corresponding to an estimated C/N-ratio of 0.05) followed by a 4 ⁇ m thick TiCN-layer with columnar grains by using the MTCVD-technique (temperature 885-850° C. and CH 3 CN as the carbon and nitrogen sources).
• a 1.0 ⁇ m thick layer of Al 2 O 3 was deposited using a temperature 970° C. and a concentration of H 2 S dopant of 0.4% as disclosed in EP-A-523 021.
• a thin (0.3 ⁇ m) layer of TiN was deposited on top according to known CVD-technique. XRD-measurement showed that the Al 2 O 3 -layer consisted of 100% ⁇ -phase.
• the coated inserts were brushed by a nylon straw brush containing SiC grains. Examination of the brushed inserts in a light microscope showed that the thin TiN-layer had been brushed away only along the cutting edge leaving there a smooth Al 2 O 3 -layer surface.
• Coating thickness measurements on cross sectioned brush samples showed no reduction of the coating along the edge line except for the outer TiN-layer that was removed.
• Cemented carbide tool inserts of the type SEMN 1204 AZ, an insert for milling, with the composition 9.1 wt % Co, 1.23 wt % TaC and 0.30 wt % NbC and the rest WC with unimodal distribution and an average grain size of 1.2 ⁇ m were produced in the following way.
• Cobalt coated WC, WC-6 weight-% Co, prepared in accordance with U.S. Pat. No. 5,505,902 was carefully deagglomerated in a laboratory jetmill equipment, mixed with additional amounts of Co and deagglomerated uncoated (Ta,Nb)C and TaC powders to obtain the desired material composition.
• the mixing was carried out in an ethanol and water solution (0.25 l fluid per kg cemented carbide powder) for 2 hours in a laboratory mixer and the batch size was 10 kg. Furthermore, 2 weight-% lubricant, was added to the slurry. The carbon content was adjusted with carbon black to a binder phase highly alloyed with W corresponding to a CW-ratio of 0.89. After spray drying, the inserts were pressed and sintered according to standard practise and dense structures with no porosity were obtained.
• the inserts were coated in the same coating batch as the inserts A above.
• the coated inserts were brushed by a nylon straw brush containing SiC grains. Examination of the brushbed inserts in a light microscope showed that the thin TiN-layer had been brushed away only along the cutting edge leaving there a smooth Al 2 O 3 -layer surface.
• Coating thickness measurements on cross sectioned brushed samples showed no reduction of the coating along the edge line except for the outer TiN-layer that was removed.
• Two parallel bars each of a thickness of 35 mm were centrally positioned relative the cutter body (diameter 100 mm ), and the bars were placed with an air gap of 10 mm between them.
• the cutting data were:

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Mechanical Coupling Of Light Guides (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Cutting Tools, Boring Holders, And Turrets (AREA)
• Powder Metallurgy (AREA)

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• 1996
  • 1996-07-19 SE SE9602821A patent/SE511817C2/sv not_active IP Right Cessation
• 1997
  • 1997-07-08 US US11/484,834 patent/USRE41646E1/en not_active Expired - Lifetime
  • 1997-07-15 EP EP97850115A patent/EP0819958B1/de not_active Expired - Lifetime
  • 1997-07-15 DE DE69738121T patent/DE69738121T2/de not_active Expired - Lifetime
  • 1997-07-16 US US08/895,573 patent/US5850283A/en not_active Expired - Lifetime
  • 1997-07-18 JP JP9226997A patent/JPH10307227A/ja active Pending

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