Patents Assigned to Nippon Tungsten Co., Ltd.
  • Patent number: 4430440
    Abstract: A material for magnetic head sliders comprises a mixed powder consisting of 40 to 80% by weight of Al.sub.2 O.sub.3 and 20 to 60% by weight of TiO.sub.2, and further contains, per 100 parts by weight of the Al.sub.2 O.sub.3 and TiO.sub.2 mixture, 0.5 to 5 parts by weight of at least one of CaO, MgO and Y.sub.2 O.sub.3, and 0.5 to 10 parts by weight of ZrO.sub.2.
    Type: Grant
    Filed: May 28, 1982
    Date of Patent: February 7, 1984
    Assignees: Sumitomo Special Metal Co. Ltd., Nippon Tungsten Co., Ltd.
    Inventors: Toshiaki Wada, Mitsuhiko Furukawa, Michito Miyahara, Masaharu Shiroyama, Kiyohito Misumi, Takashi Kitahira
  • Patent number: 4422874
    Abstract: The present invention relates to a method for producing golden sintered alloys for ornamental purposes and suitable for use in watches. They are mainly composed of 10-40 percent by weight of titanium nitride, 10-30 percent by weight of nickel and valanced niobium carbide. Less than 40 percent by weight of the nickel may be substituted by at least one member from the group of chromium, molybdenum, tungsten and titanium. The alloys have a high degree of hardness (Rockwell A scale), excellent corrosion resistance and a beautiful gold color.
    Type: Grant
    Filed: January 6, 1982
    Date of Patent: December 27, 1983
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Tomio Nishimura, Hiraku Yoshino, Kosei Takao, Yuuji Masumoto
  • Patent number: 4356272
    Abstract: Sintered bodies having improved sinterability and toughness consist essentially of: (1) 100 parts by weight of titanium carbide, titanium oxide and aluminum oxide, the titanium carbide and titanium oxide accounting for 15 to 60 percent by weight and the aluminum oxide accounting for 85 to 40 percent by weight, the amount of titanium oxide relative to the titanium carbide and titanium oxide being 5 to 15 percent by weight, and (2) 0.039 to 1.575 parts by weight of yttrium. Sintering aids may include at least one of the oxides of magnesium, nickel, molybdenum, chromium, cobalt, iron and manganese.
    Type: Grant
    Filed: March 24, 1981
    Date of Patent: October 26, 1982
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Yutaka Kanemitsu, Takehiko Hagio, Mitsuhiko Furukawa, Michito Miyahara, Yoshimichi Hara, Takashi Kitahira
  • Patent number: 4292078
    Abstract: Electrical contact material of this invention consists of 10 to 20 percent by weight of nickel, 0.05 to 2 percent by weight of titanium boride and the balance tungsten. Conventionally, nickel-tungsten alloy shows poor mechanical properties (e.g. brittleness) although the alloy shows high oxidation resistance and can be produced in an inexpensive way. Inclusion of titanium boride greatly improves the mechanical properties of such alloy, thereby enabling the cheap production of electrical contact material which has sufficient practical use.
    Type: Grant
    Filed: November 5, 1979
    Date of Patent: September 29, 1981
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Sinya Honda, Takeshi Komura, Naomi Sugita, Tatuya Okamoto
  • Patent number: 4280841
    Abstract: This invention relates to the manufacture of a mechanical seal ring provided with a cemented carbide hardened layer or ring which is firmly bound to a substrate of a mechanical seal ring and is of sufficient hardness.The method is substantially characterized by the use of Ni--P alloy as a binder between the cemented carbide layer and the substrate.In the manufacturing process, after a presintered carbide compact made of hard carbide powder such as tungsten carbide powder is applied to a groove of the substrate, the Ni--P alloy in either paste form or compacted and sintered compact form is applied onto the presintered carbide compact and finally is sintered in a non-oxidizing furnace. In the above sintering process, Ni and P infiltrates and diffuses into the substrate and the presintered carbide compact whereby the cemented carbide hardened layer and the substrate can be firmly bound to each other due to the metallurgical bonding therebetween.
    Type: Grant
    Filed: September 6, 1978
    Date of Patent: July 28, 1981
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Hiroshi Ito, Shigeya Sakaguchi
  • Patent number: 4249914
    Abstract: The powder mixture consisting of 0.5 to 5 percent by weight of TiN and 99.5 to 95 percent by weight of Al.sub.2 O.sub.3 is first presintered and is subsequently subjected to a hot isostatic pressing so as to produce a sintered product which has the maximum grain size of 2 .mu.m and the hardness of more than H.sub.R A 94.Such sintered product is used as a cutting tool for a high-speed continuous cutting operation.
    Type: Grant
    Filed: April 18, 1978
    Date of Patent: February 10, 1981
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Kazuki Ogawa, Mitsuhiko Furukawa, Yoshimichi Hara, Takashi Kitahira
  • Patent number: 4108652
    Abstract: A new hot isostatic pressing method produces sintered material having a very fine structure as well as uniform properties by forming a unique capsule such as a titanium capsule of metal over a presintered material for sintering a ceramic cutting tool material is disclosed.
    Type: Grant
    Filed: August 17, 1976
    Date of Patent: August 22, 1978
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Kazuki Ogawa, Mitsue Koizumi, Mitsuhiko Furukawa, Yoshimichi Hara, Takashi Kitahira
  • Patent number: 4063908
    Abstract: Sintering of a mixture of alumina and titanium carbide has been difficult heretofore, but by the intermediary action of titanium oxides, sintering of a powder mixture consisting of alumina and titanium carbide by hot-pressing at a comparatively lower temperature than that used in conventional processes becomes possible. Various procedures in which the above principle is applied, the powder mixture to be used therein and the materials produced thereby which are to be used for manuacturing cutting tools are disclosed.
    Type: Grant
    Filed: January 21, 1976
    Date of Patent: December 20, 1977
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Kazuki Ogawa, Michito Miyahara, Mitsuhiko Furukawa
  • Patent number: 4044217
    Abstract: There is disclosed a sliding surface working method using wire-explosion spray coating according to which the inner surface of an aluminium alloy cylinder is wire-explosion spray coated using a molybdenum wire, molybdenum-tungsten alloy wire, or tungsten wire. Next, the inner surface is alternately and repeatedly wire-explosion spray coated by alternately wire-explosion spraying a carbon steel wire and a wire of a material having good seizure resistance and wear resistance characteristics. Finally, the inner surface thus coated is ground and finished.
    Type: Grant
    Filed: May 7, 1975
    Date of Patent: August 23, 1977
    Assignees: Kawasaki Jukogyo Kabushiki Kaisha, Nippon Tungsten Co., Ltd.
    Inventors: Yukio Otsuki, Hiroyuki Matsumoto, Hiroshi Ito, Shusuke Takezaki
  • Patent number: 4014140
    Abstract: Apparatus and method for automatically chamferring edges and corners of rectangular articles. According to the invention, an article blank is subjected, under control of a guiding means, to a grinding wheel for grinding the edges of the blank. A turning means is provided to change the orientation of the blank as the grinding means grinds a corner of the blank, the turning means adapted to give a complete revolution to the blank for chamferring all its edges and corners. A discharge device discharges the finished blank out of the apparatus.
    Type: Grant
    Filed: February 17, 1976
    Date of Patent: March 29, 1977
    Assignee: Nippon Tungsten Co., Ltd.
    Inventors: Sueo Aoki, Nobumasa Amamoto