Patents Assigned to Yoshiwa Kogyo Kabushiki Kaisha
  • Patent number: 4000011
    Abstract: A method of surface hardening for forming a hardened layer of cemented carbide, including cementite, on a local surface area of cast iron by rapidly melting the local surface by means of a rapid melting process such as the electron bombardment melting process to form a molten pool thereon, then rapidly cooling the molten pool by the chilling effect of the non-molten portion of cast iron and finally finishing the cast iron having the hardened layer thus formed to a desired shape. To this end, the cast iron used contains therein one or a mixture of deoxidizing agents such as aluminum, magnesium and calcium.
    Type: Grant
    Filed: September 7, 1972
    Date of Patent: December 28, 1976
    Assignees: Toyo Kogyo Co., Ltd., Yoshiwa Kogyo Kabushiki Kaisha
    Inventors: Nobuaki Sato, Katsuro Yamasaki