Loading patent…
AssigneesKabushiki Kaisha Toshiba, Toshiba Ceramics Co., Ltd.
InventorsToshio Shikata, Hirokazu Tokoro, Takanobu Nishimura, Masaharu Kinoshita, Norio Masuda
Estimating the term…
Spherical graphite cast iron utilized to prepare a lapping tool is manufactured by casting a molten composition into a mold cavity, and by chilling one side of the resulting casting thereby causing unidirectional solidification, the one side being used as the operating surface of the lapping tool. The molten composition consists essentially of 3.0-3.8 wt. % of carbon, 2.0-2.9 wt. % of silicon, 0.3-0.9 wt. % of manganese, less than 0.05 wt. % of phosphorus, less than 0.03 wt. % of sulfur, 0.2-1.0 wt. % of nickel, 0-0.8 wt. % of copper, 0.05-0.5 wt. % of molybdenum, 0.03-0.09 wt. % of magnesium and the balance of iron. The lapping tool made of this casting has a percentage of sphericity of higher than 80%, graphite particle diameter of less than 100 microns, a density of graphite particles of larger than 70/mm.sup.2, and a Vickers hardness of larger than 200.
A method of manufacturing spherical graphite cast iron suitable for preparing a lapping tool, comprising the steps of pouring into a mould cavity a molten composition to provide a form, said molten composition consisting essentially of 3.0-3.8 weight % of carbon, 2.0-2.9 weight % of silicon, 0.3-0.9 weight % of manganese, less than 0.05 weight % of phosphorus, less than 0.03 weight % of sulfur, 0.2-1.0 weight % of nickel, 0-0.8 weight % of copper, 0.05-0.5 weight % of molybdenum, 0.03-0.09 weight % of magnesium and the balance of iron;
A method of manufacturing spherical graphite cast iron suitable for preparing a lapping tool, comprising the steps of producing a casting by pouring into a mould cavity a molten composition to provide a form, wherein said composition consists essentially of 3.0-3.8 weight % of carbon, 2.0-2.9 weight % of silicon, 0.3-0.9 weight % of manganese, less than 0.05 weight % of phosphorus, less than 0.03 weight % of sulfur, 0.0.8 weight % of copper, less than 0.05 weight % of molybdenum, 0.03-0.09 weight % of magnesium and the balance of iron;
A method of manufacturing spherical graphite cast iron suitable for preparing a lapping tool, comprising the steps of producing a casting by pouring into a mould cavity a molten composition to provide a form, said molten composition consists essentially of 3-3.8 weight % of carbon,2.0-2.9 weight % of silicon, 0.3-0.9 weight % of manganese, less than 0.05 weight % of phosphorus, less than 0.03 weight % of sulfur, 0.2-1.0 weight % of nickel, 0-0.8 weight % of copper, 0.1-0.5 weight % of molybdenum, 0.03-0.09 weight % of magnesium and the balance of iron;
A method of manufacturing spherical graphite cast iron suitable for preparing a lapping tool, comprising the steps of producing a casting by pouring into a mould cavity a molten composition to provide a form, said molten composition consisting essentially of 3-3.8 weight % of carbon, 2.0-2.9 weight of silicon, 0.3-0.9 weight % of manganese, less than 0.05 weight % of phosphorus, less than 0.03 weight % of sulfur, 0.2-1.0 weight % of nickel, 0-0.8 weight % of copper, 0.1-0.5 weight % of molybdenum, 0.03-0.09 weight of magnesium, and the balance of iron;
Dependencies are inferred from the claim text.