DE1483653B1 - Process for casting tubular metal hollow bodies - Google Patents

Claims (3)

1 2 The invention relates to a method for casting the molten metal during the ervon tubular metal hollow bodies after the rigid on the wall of the casting mold to a hollow low-pressure casting process, in which the molten body is the described advantageous »washing metal from a closed crucible In one effect at each stage of the wall thickness build-up, the casting mold is pressed upwards, the metal being achieved 5, whereby the product formed becomes homogeneous over its entire cross-section in the casting mold for a sufficient time and of let-in to be on the wall of the casting mold finally has a free grain structure,
a solid hollow body of the desired strength.This axial oscillation of the molten Mezu solidifies and then the remaining molten tail in the casting mold can best be drained through fort metal from the solidified metal hollow body into the io while the gas pressure changes on the bath crucible will. mirror in the closed crucible. It is known in continuous casting processes (British The invention also consists in the metal patent 793 356) to apply oscillations between pressure oscillations by a superimposed alternating oscillation in an axial oscillation of a frequency, which is 0.2 and 1 period per second and an amplitude a continuous manufacturing process 15 is offset by approximately 15 cm,
cast metal ingot or the like, with molten The method according to the invention is carried upwards through a casting mold with a zenes metal, low-pressure casting device known per se. The product is carried out by suitable means and subsequently by means of a scheder mold, e.g. B. by rolling, pulled. The geometric drawing is described, for example,
Molten metal is according to and through the 20 In the drawing has a crucible 1, the example casting mold can be heated by the combined action of gas, a lining 2 and, under static pressure and under pulsing, holds molten metal 3 in one perpendicular λ led to intermittent pressure. The latter is superimposed on the tubular shape 4. A pressurized gas inlet 7 ™ controls the static pressure and ensures that this does not stick to a space above the bath level in the tie metal in the casting mold. 25 gel 1 completed above. Form 4 In the case of tubular hollow bodies, which after running through a stuffing box 8 in order to Low-pressure casting processes are produced, have zene metal 3 to achieve. the bores often have irregularities such as In use the pressure of the through Peaks, holes or coarse toothed grain structure the inlet 7 entering gas that the metal in on, which only increases through relatively expensive post-processing 3 ° of form 4. Metal is made in the form can be removed so that the hollow body can be left for such a period of time that is sufficient as a starting product for the production of highly qualified in order to keep the metal in contact with the casting mold ter tubes can be used. To allow a hollow body to solidify, This is important in the production of steel that has a desired wall thickness. The pressure tubes made of steel alloys, especially stainless steel. 35 on the molten metal in the furnace 2 This problem is of particular concern, then drained and the remaining molten if thick-walled pipes with small bores he metal in the casting mold is generated in the furnace body should be. given and leaves in the mold a tubular The object of the invention is to provide a method for producing hollow bodies of the desired wall thickness. The casting mold, after the tubular metal hollow body 4 ° form, is removed from the stuffing box 8 and the low-pressure casting process with a perfect metal hollow body is removed from the casting mold.
Crystal structure and a smooth inner surface. The mold 4 can be placed at its upper end with a. refractory lining sleeve 10 of low grade - To achieve this goal, the molten conductivity is provided to reduce the heat loss so \ zene metal in the time in which the solid tube 45 that the formation of a cap or shaped hollow body on the wall of the casting mold bridge made of solid metal at the upper end of the deformed metal hollow body standing in the mold several times in the axial direction is prevented,
moves up and down. The method has produced significant technical and economic advantages for the implementation of the invention, driving is a suitable vibration pressure because now there is no costly reworking of the drilling 50 the metal 3 in the furnace body 1 through the grooves in the tubes produced in this way. let 7 be applied, this vibration When carrying out the supply pressure according to the invention superimposed on a static pressure The method has shown that, for example, is that has been applied through the inlet 7. the production of thick-walled hollow bodies with relatively small bore a factor that makes 55 claims:
is the speed at which the molten metal is made the bore of the resulting hollow body from the 1st process for casting tubular Form is drained into the crucible because of the metal hollow bodies after the low pressure rapid Reflux of the molten metal from casting processes, in which the molten metal the bore of the resulting hollow body is a 60 from a closed crucible into a casting mold "Washing effect" exerts, the weak dendritic is pushed upwards, whereby the metal in the Excesses and other protruding parts on the mold for a sufficient amount of time left the bore wall removed and so the remaining is sen to a solid hollow body of the desired on the wall of the casting mold from pockets and droplets of molten metal and to solidify irregularities at and near the upper thickness and then the rest of the surface the wall of the bore of the finished molten metal from the solidified hollow metal body prevented. Hollow body is drained into the crucible, d a - Characterized by the relatively slow axial oscillation, that the molten metal several times during the time in which the solid tubular hollow body is formed is moved up and down in the axial direction in the mold. 2. The method according to claim 1, characterized in that the axial vibration of the molten Metal is generated by continually changing the gas pressure on the bath level in the closed crucible. 3. The method according to claim 1 or 2, characterized in that the metal in an axial Oscillation with a frequency between 0.2 and 1 period per second and an amplitude of is offset about 15 cm. 1 sheet of drawings