FR2611525A1 - CRYSTALLIZER - Google Patents

Abstract

THE INVENTION RELATES TO A CRYSTALLISER. ACCORDING TO THE INVENTION, IT INCLUDES A COPPER BUSH 1 PROVIDED WITH STEEL RIGIDITY RIBS 2 AND A STEEL SHIRT 3 ARRANGED COAXIAL WITH THE BUSH 1 AND WITH IT FORMING A COOLING CAVITY 4 DIVIDED INTO CHANNELS 5 BY THE RIBS OF RIGIDITY 2, THESE RIBS 2 PENETRATING IN THE BUSH 1 AND WITH IT FORMING A BIMETALLIC COUPLING FOLLOWING THE CONTACT SURFACE. THE INVENTION APPLIES IN PARTICULAR TO STEEL INDUSTRY.

Description

The invention relates to iron and steel and more particularly to

  crystallizing. The invention can be

  used for remelting the electroslagged metal

  conductor, arc vacuum and electron beam and is applied to different branches of the steel industry, in mechanical engineering, aviation, shipbuilding, to obtain high quality ingots to

given structure of the metal.

  There is a crystallizer (see Medovar BN et al., "Electroslag slag furnaces", Kiev, "Naukova dumka", 1976, page 91) for remelting, which comprises a copper or alloy bushing and a steel jacket arranged coaxially with the socket and

  forming therewith a closed cooling cavity.

  Such a construction of the crystallizer has a low rigidity to exploitation because the copper of the sleeve is insufficiently rigid, which puts quickly

  the crystallizer out of service because during use

  sation, the copper bushing is subject to strong thermal stresses on the wall. In the thickness of the

  copper wall, strong temperature gradients are observed

  from 5 to 10 C / mm. This causes the appearance of strong thermal stresses in the wall and, therefore,

  its deformation. This is why the construction of the crystal-

  reflow is subject to very high demands. There is also a crystallizer (see US Pat. No. 3,899,017, published Aug. 12, 1975) which comprises a copper bushing with stiffness ribs and a steel jacket arranged coaxially with the sleeve and forming with it a divided cooling cavity. channels through stiffness ribs. Each rib is fixed along its length, for example by welding, to the outer wall of the sleeve of the crystallizer. The known crystallizer is characterized by the insufficient rigidity of the copper sleeve. The thermal stresses appearing in its walls cause deformation of the copper bushing and its decommissioning before term because the welds of the ribs to the wall of the sleeve do not have a sufficient resistance to prevent the separation of the ribs and the wall of the socket. Therefore, during the heating of the sleeve at the time of reflow, it is subject to thermal expansion, is deformed and, therefore, the coupling between the stiffness ribs and the wall of the sleeve is destroyed. If the deformations are notable, it is impossible to remove the ingot of the crystallizer which must be repaired.

  The object of the invention is to create a crystalline

  which has high reliability and good rigidity as a result of the improved coupling of the

  copper bushing with stiffness ribs.

  The goal is obtained because, in the crystalli-

  evening with a copper bushing with ribs

  steel stiffness and a steel jacket arranged

  axially to the copper bushing and forming with it a cooling cavity divided into channels by the steel stiffness ribs, according to the invention, the stiffness ribs of steel penetrate the copper bushing and form with it a bimetallic coupling

following the contact surface.

  Thus, the stiffness and reliability of coupling the bushing with the stiffness ribs are increased, which increases the rigidity and the resistance of the bushing, during use, and the crystallizer itself. In addition, this construction saves non-ferrous metals (copper, chrome bronzes) because

  it is possible to make a thin-walled socket.

  The invention will be better understood, and other purposes, features, details and advantages thereof

  will become clearer during the description

  explanatory text which will follow with reference to the accompanying schematic drawings given solely by way of example illustrating an embodiment of the invention and in

26 1525

  which: - Figure 1 shows a crystallizer, in vertical section through the pipes, according to the invention; and

  - Figure 2 shows a horizontal section.

  The crystallizer has a copper sleeve 1

  (FIG. 1) provided with rigidity ribs 2 made of steel,

  What is welded is a 3 'steel sleeve arranged

  axially with respect to the copper sleeve 1 and forming with it a cooling cavity 4 divided by the

  stiffness ribs 2 in channels 5 for the coolant

  sor. The stiffness ribs 2 penetrate into the sleeve 1, as shown in Figure 2, and form with it a bimetallic coupling along the entire contact surface. The cooling agent is introduced into the cavity 4 by means of tubings 6 (FIG. 1) and is evacuated via tubings 7. The remelting of the consumable electrodes 8 is done in a slag bath 9 with subsequent formation.

  10. The stiffness ribs 2 can penetrate

  tren in socket 1 at different depths. The

  maximum stiffness of sleeve I corresponds to the penetration

  2 in the sleeve 1, equal to the thickness of the wall of the sleeve 1. However, for certain refusals, for example, the melting in a vacuum arc furnace highly reactive metals (titanium,

  zirconium), the presence in the useful space of the crystalline

  evening, steel elements, is undesirable because it can deteriorate the quality of the metal obtained. Besides this,

  the penetration value depends on the thermo-

  concrete physics of the melting process and cooling conditions. This is why the depth of penetration of the stiffness rib 2 into the wall of the sleeve 1 is chosen for each specific case and lies within the limits of 0.3 to 1.0 of the thickness of

the wall of the socket 1.

  The crystallizer works as follows.

  The crystallizer is installed on a cheese (which is not shown in the drawing). The cooling liquid is fed into the channels 5 through the pipes 6 and is discharged through the pipes 7. In the lower part of the sleeve 1 installed on the cheese is formed a slag bath 9 into which the electrode 8 is introduced. A tension is applied to the slag bath 9 and the heating and remelting of the consumable electrode 8 is begun. The molten metal passes through the slag bath 9 and forms, in the lower part

of the sleeve 1, the ingot.

  During electroconductive slag remelting, the crystallizer elements are subjected to high thermal stress due to liquid slag and metal.

6 2

  which reach (0.5 to 1.5) - 10 W / m2. In this case, in the thickness of the wall of the sleeve 1, there are high thermal stresses which can lead to irreversible deformations. The presence of stiffness ribs 2 penetrating into the copper bushing 1 and forming a bimetallic coupling therewith substantially increases the rigidity of the construction and provides the desired rigidity and reliability of the crystallizer. In the present construction are missing the rubber sealing elements of the steel jacket 3 and the sleeve 1

  which, in the crystallizers, are rapidly out of order.

  In addition to this, the bimetallic coupling of the stiffness ribs with the sleeve 1 makes it possible, while preserving the same rigidity of the crystallizer, to reduce the thickness of the copper wall of the sleeve 1 which, in turn, makes it possible to reduce the Copper consumption and erosion of the socket 1. All this gives the possibility of raising the reliability of the crystallizer, one of the main organs

for remelting processes.

R E V E N D I CA T I O N

  Crystallizer of the type comprising a copper bushing provided with ribs of steel rigidity and a steel jacket disposed coaxially with respect to the copper bushing and forming with it a cooling cavity divided by the channel stiffness ribs in steel, characterized in that the stiffening ribs (2) made of steel penetrate into the copper bushing (1) and form with it a bimetallic coupling

following the contact surface.