Daido Tokushuko Kabushiki Kaisha

Daido Tokushuko K.k.

Daido Tokushuko Kaisha

Noboru Demukai

Saburo Sugiura

Kenji Kanada

Junji Yamada

Tetsuo Okamoto

Kiyohide Hayashi

Senji Fujita

Sabro Sugiura

Masanobu Ikeda

Masayuki Yamamoto

Junichi Tsubokura

Tetuo Okamoto

Shingo Hitotsuyanagi

A melting apparatus having a compact structure, of economical equipment cost, enabling to vacuum melting and refining at high productivity. A metal melting apparatus has a structure in which a refractory furnace wall is furnished on an outer circumference thereof with a seal jacket of air tight and non-electrical conductivity, and disposed with vertical water cooling copper pipes along the inner circumference of the seal jacket at predetermined space, and the furnace casing is arranged at the outer part to encircle the furnace casing with an induction heating coil , and the furnace casing is secured to a frame by means of the seal jacket for reinforcing the structure. The seal jacket of the furnace casing is fixed to the frame via an upper flange and a lower flange

Metal melting apparatus

Disclosed is a levitation melting method comprising applying a high-frequency current to a high frequency induction coil wound around a melting crucible to induction-heat a material introduced to the melting crucible; and erecting the resulting molten metal to be in no contact with the inner wall surface of the melting crucible with the bottom of the material being maintained in the solidified state; wherein a power input P of a high-frequency power source to the high-frequency induction coil, an inner radius R at the bottom of the crucible and super heat .DELTA.T of the molten metal satisfy the relationship of P/R2=.DELTA.T.multidot.(0.0008 to 0.002), as well as, a melting and casting method for casting the molten metal prepared by the levitation melting method described above into a mold using a snout suspended above the melting crucible such that the lower end of the snout may be submerged in the molten metal.

Levitation melting method and melting and casting method

A levitation melting method and device through which a material having various configurations can be melted through efficient induction heating. First, a starting material(WB), whose outer diameter has been adapted to the inner diameter of a crucible(13), is inserted in crucible(13). The crucible(13) is shielded with argon gas, thereby starting the melting of the material(WB) to molten metal(WM). Subsequently, a suction tube(33) of a mold(31) is inserted into the molten metal(WM) for drawing a part of molten metal(WM) up into the mold(31) for casting. After part of the molten metal(WM) is drawn up, a sliding cover(15) is slid such that a material holder(19) is positioned right above the crucible(13). By opening a sliding plate(35) of the material holder(19), material pieces(WS) are inserted from the material holder(19) into the molten metal(WM) left in the crucible(13). Since gaps in the material pieces(WS) are filled with the molten metal(WM), a dense bulk is formed which is to be melted through induction heating.

Levitation melting method and a levitation melting and casting device

Molten metal melted in a levitation melting furnace is cast through a suction pipe immersed therein from above into a mold having a gas permeability in a double-structure mold chamber arranged directly above the melting furnace. The metal is levitation-melted in an inert atmosphere under atmospheric pressure. An outer mold chamber of the double-structure mold chamber is joined to the levitation melting furnace. Pressure in the outer mold chamber and in an inner mold chamber of the double-structure mold chamber and in an upper space in the levitation melting furnace is reduced to below atmospheric pressure. The suction pipe arranged in the inner mold chamber and communicating with the mold therein is immersed into the molten metal. The molten metal is cast into the mold under an increased pressure by blowing an inert gas into the upper space in the melting furnace. The inner mold chamber is raised, thereby pulling out the suction pipe from the molten metal. The outer mold chamber is raised after being returned to atmospheric pressure to separate from the melting furnace.

Method for casting metal and apparatus therefor

Disclosed is a levitation melting crucible which can facilitate penetration of magnetism into the crucible and which can prevent a molten metal from being contaminated by an insulating material. The levatation melting crucible comprises a cylindrical main body having a closed bottom, a plurality of slits defined vertically in the circumferential wall of the main body to open inward and outward at predetermined intervals in the circumferential direction and an insulating material filled in each of the slits; wherein each slit is designed to have an inner opening width smaller than its outer opening width, with respect to the radius of the main body, for example, 1.5 A&gt;B.

Levitation melting crucibles

Precision casting of titanium or titanium alloy includes establishing molten metal by induction heating in an assembly formed with water cooled copper segments disposed circlewise on the inside of an induction coil in a state insulated from each other and casting the molten metal into a permeable mold by vacuum casting. The precision casting method uses apparatus including an induction coil, an assembly formed with the aforementioned copper segments, an arrangement for feeding a base metal from the under side thereof and a permeable mold into which the molten base metal in the assembly is transferred by vacuum casting. It is possible to obtain precision castings of metal having high melting points and high actvitiy such as titanium, titanium alloy or the like.

Method for precision casting of titanium or titanium alloy

An apparatus is disclosed for producing metal powder having a molten metal holding vessel with a generally cylindrical shaped bottom portion, a molten metal discharging runner located at the bottom portion of the holding vessel, a spraying chamber connected at a lower end of the discharging runner, a first induction heating coil having a diameter and surrounding the holding vessel, a second induction heating coil surrounding the discharging runner, and a ring-shaped magnetic shielding plate disposed between the second induction heating coil and the sliding gate. The discharging runner has a nozzle portion which includes a sliding gate made of ceramic. The sliding gate is movable for controlling the flow of the molten metal through the nozzle portion of the discharging runner. The spraying chamber has gas-jetting nozzles. The second induction heating coil has a diameter smaller than a diameter of the first induction heating coil.

Apparatus for production metal powder having a shielded runner nozzle

A reactor for iron making having an upper gas blowing nozzle, a lower gas blowing nozzle, and an iron scrap charging inlet. A vertical shaft is installed directly above the inlet at the top part of the reactor. A mechanism is provided in the lower end of the vertical shaft for controlling charging of the iron scrap to the reactor. A by-pass tube is connected between the top part of the reactor and a gas inlet in the vertical shaft directly above the mechanism for controlling the charging of iron scrap and permits exit of high temperature exhaust gases from the reactor and introduces the exhaust gases to flow through the iron scrap in the vertical shaft to pre-heat the same. Structure is provided in the by-pass tube for introducing oxygen gas or air into the high temperature exhaust gases to react therewith and generate further heat. The structure can comprise a nozzle. The mechanism for controlling charging of iron scrap can include a damper positioned immediately above the inlet in the top part of the reactor which is movable to open and close the vertical shaft together with a stopper positioned above the damper and movable to open and close the vertical shaft. Certain amounts of iron scrap can thereby be charged to the reactor by sequential openings and closings of the damper and the stopper.

Reactor for iron making

An improvement to a scrap melting method employing an electric arc furnace, which comprises the step of heating the scrap by a powdered coal burner prior to the step of heating the scrap by the electric arc. The burning conditions are controlled so as to reduce the amount of oxidized Fe as well as the amount of NO.sub.x contained in the exhaust gases. In preferred embodiments, a pair of furnaces are employed to heat the scrap alternately by the powdered coal burner and by the electric arc.

Scrap melting method

An improved apparatus for reactor iron making has a furnace body to melt raw material, typically as scrap, a shaft to heat the raw material, and a raw material supply bucket, these three components being arranged vertically, with an exhaust gas combustion tower positioned close to the shaft. Raw material is supplied to the shaft with this apparatus by the bucket, and, after being heated by exhaust gas from the furnace body, the raw material is charged into the furnace body by the opening/closing operation of a shaft damper and a furnace body cover. Exhaust gas is introduced from the furnace body into the combination tower, air is supplied in stages, the temperature of the gas is gradually raised through combustion of CO, and the gas is used to heat the raw material in the shaft.

Apparatus for reactor iron making

A powdered coal burner used for directly heating an object to be heated, particularly iron scrap, in a heating vessel. The burner is composed of an oxygen nozzle, a powdered coal nozzle, an air nozzle, disposed concentrically from the center, and a cone which is provided at the end of the opening part of the oxygen nozzle in such a way as to disperse oxygen in a radial direction and burn powdered coal. The burner burns with shortened length of flame, and temperature of the flame is not excessively high.

Powdered coal burner

During the heating of scrap in a container using sulfur-containing fuels for combustion, CaO, Ca(CO).sub.2, or CaCO.sub.3 powder is injected into the container to fix sulfur oxides generated during the combustion mainly as CaSO.sub.4. There is no need for special exhaust gas desulfurization, and, at the same time, slag formation is possible.

Scrap heating method

Method of reactor iron making without using electric power in the reactor. Iron scrap and a solid non-petroleum carbonaceous material, i.e., powdery coal or coke, are continuously charged from above into molten iron in the reactor with a space over the molten iron. The carbonaceous material is charged by injecting it with a stream of nitrogen or air. Oxygen gas is simultaneously blown into molten iron below its surface so as to stir it and oxidize the carbonaceous material mainly to CO and blown into the space over the iron to oxidize the CO to CO.sub.2. The amount of oxygen is increased as the amount of molten iron increases. The iron scrap melts from the heat generated by the oxidation. The high temperature exhaust gas is used to preheat scrap to be charged. When the amount of molten iron reaches a predetermined level, it is tapped off until a lower predetermined level is reached. The above steps are repeated. Twin reactor iron making can use the method. Only part of the CO produced in one reactor is oxidized and high temperature exhaust gas is passed to the other reactor while oxygen is added thereto to oxidize the remainder and generate more heat. The heat of the gases and the additional heat of oxidation preheats scrap and carbonaceous material in that reactor.

Reactor iron making

A method of melting iron scrap using an arc furnace with reduced electric power consumption. In one of a pair of vessels which are arc furnace bodies, melting of the scrap by heat of arc is carried out while a carbonaceous material and oxygen-containing gas are introduced therein to cause oxidation of C to CO to make use of the oxidation heat. Thus formed hot exhaust gas containing CO is introduced to the other vessel of the pair and oxygen-containing gas is added thereto to cause oxidation of CO to CO.sub.2 thereby heating the scrap loaded in the vessel. Melting is further continued by changing the roles of the two vessels to each other. Generation of the CO-containing hot gas can be performed in a separately installed gasification furnace.

Growing community of inventors

Gifu, Japan

Noboru Demukai