Abstract: A method for manufacturing an austempered ductile cast iron and a product made from the austempered ductile cast iron manufactured by the method are disclosed. In the method for manufacturing an austempered ductile cast iron, spheroidizing agent and primary inoculant are added to a raw molten metal to create homogeneous spheroidal graphite creation in a deep part of a matrix and the raw molten metal to which the spheroidizing agent and the primary inoculant are added is injected into a mold to which secondary inoculant is locally applied, to micronize spheroidal graphite of a local structure coated with the secondary inoculant into fine graphite that is easy to machine, thereby enhancing workability as compared with a conventional austempered ductile cast iron.

Abstract: A method for manufacturing an austempered ductile cast iron and a product made from the austempered ductile cast iron manufactured by the method are disclosed. In the method for manufacturing an austempered ductile cast iron, spheroidizing agent and primary inoculant are added to a raw molten metal to create homogeneous spheroidal graphite creation in a deep part of a matrix and the raw molten metal to which the spheroidizing agent and the primary inoculant are added is injected into a mold to which secondary inoculant is locally applied, to micronize spheroidal graphite of a local structure coated with the secondary inoculant into fine graphite that is easy to machine, thereby enhancing workability as compared with a conventional austempered ductile cast iron.

Abstract: A method for manufacturing an austempered ductile cast iron and a product made from the austempered ductile cast iron manufactured by the method are disclosed. In the method for manufacturing an austempered ductile cast iron, spheroidizing agent and primary inoculant are added to a raw molten metal to create homogeneous spheroidal graphite creation in a deep part of a matrix and the raw molten metal to which the spheroidizing agent and the primary inoculant are added is injected into a mold to which secondary inoculant is locally applied, to micronize spheroidal graphite of a local structure coated with the secondary inoculant into fine graphite that is easy to machine, thereby enhancing workability as compared with a conventional austempered ductile cast iron.

Abstract: A method for manufacturing an austempered ductile cast iron and a product made from the austempered ductile cast iron manufactured by the method are disclosed. In the method for manufacturing an austempered ductile cast iron, spheroidizing agent and primary inoculant are added to a raw molten metal to create homogeneous spheroidal graphite creation in a deep part of a matrix and the raw molten metal to which the spheroidizing agent and the primary inoculant are added is injected into a mold to which secondary inoculant is locally applied, to micronize spheroidal graphite of a local structure coated with the secondary inoculant into fine graphite that is easy to machine, thereby enhancing workability as compared with a conventional austempered ductile cast iron.

Abstract: Disclosed herein is a high strength special steel including, by weight %: carbon (C): from about 0.1 to 0.5%; silicon (Si): from about 0.1 to 2.3%; manganese (Mn): from about 0.3 to 1.5%; chromium (Cr): from about 1.1 to 4.0%; molybdenum (Mo): from about 0.3 to 1.5%; nickel (Ni): from about 0.1 to 4.0%; vanadium (V): from about 0.01 to 0.50%; boron (B): from about 0.001 to 0.010%; niobium (Nb): from about 0.05 to 0.50%; and the balance of iron (Fe) and inevitable impurities.

Abstract: Disclosed herein is a high strength special steel including, by weight %: carbon (C): from about 0.1 to 0.5%; silicon (Si): from about 0.1 to 2.3%; manganese (Mn): from about 0.3 to 1.5%; chromium (Cr): from about 1.1 to 4.0%; molybdenum (Mo): from about 0.3 to 1.5%; nickel (Ni): from about 0.1 to 4.0%; vanadium (V): from about 0.01 to 0.50%; boron (B): from about 0.001 to 0.010%; niobium (Nb): from about 0.05 to 0.50%; and the balance of iron (Fe) and inevitable impurities.

Abstract: The present invention relates to an alloy steel for a mold tool and a mold using the same. The steel for the mold tool comprises iron (Fe) as a main component, an amount of about 0.35 to 0.45 wt % of carbon (C), amount of about 0.80 to 1.20 wt % of silicon (Si), amount of about 0.20 to 0.50 wt % of manganese (Mn), amount of about 6.00 to 8.00 wt % of chromium (Cr), amount of about 1.50 to 3.00 wt % of molybdenum (Mo), and amount of about 0.80 to 1.20 wt % of vanadium (V) based on the total weight of the tool steel. Accordingly, the mold tool have improved physical properties at high temperature and extended life span.

Abstract: Disclosed is a high-strength hollow steel pipe material. The high-strength hollow steel pipe material includes Fe as a main ingredient, 0.30 to 0.40% by weight of C, 0.10 to 0.40% by weight of Si, 1.10 to 1.60% by weight of Mn, 0.20 to 0.40% by weight of Cr, 0.50 to 1.00% by weight of Ni and 0.001 to 0.005% by weight of B, the high-strength hollow steel pipe material having increased material corrosion fatigue life, compared to conventional steel pipe materials, by enhancing elongation and corrosion resistance while reinforcing strength through increase of the amounts of C and Ni conventionally added and addition of Nb and Mo as new materials.