EP1144339B1 - Method and device for producing a composite element from a ceramic inner part and a metal jacket - Google Patents

Abstract

According to known methods for producing a composite element from a truncated cone-shaped, fire-proof ceramic insert which is enclosed by a metal jacket, the outer jacket is-heated separately and shrunk on the cold ceramic insert. Alternatively, after inductive heating of the outer jacket the ceramic insert, which is heated at the same time, is positioned in the metal jacket using a mechanical device. The invention aims to provide a new method which avoids the disadvantages associated with shrinking a separately heated hot metal jacket on to a colder ceramic insert and to provide a simple method which without inductive heating of the metal jacket and the use of mechanical devices for joining said jacket to the ceramic insert achieves an even bond between the metal jacket and ceramic insert. To this end the fire-proof insert is first introduced into the metal jacket and the conical metal jacket, which rests on a support such that its opening having the smaller diameter points downwards, is then heated from the outside. During heating the ceramic insert and metal jacket remain in constant contact. After they have been heated to a sufficiently high temperature the ceramic insert slides down by force of gravity in such a way that it expands the metal jacket and moves into the bonded position. The above composite elements are used in gas stirring systems during the production of pig iron and steel.

Description

The invention relates to a method for manufacturing a composite element made of a truncated cone ceramic refractory insert made by a Sheet metal jacket is enclosed, and a device for Execution of the procedure.

Such composite elements can be used in gas purging systems Pig iron and steel production are used. In the Treatment of metallic melts in the Secondary metallurgy are considered more important Process step inert gases such as argon or nitrogen blown into the melt by gas purging systems. By the light to intensive flushing of the melt added alloys are better dissolved and it will even out the composition and the Melt temperature reached. The gas purging systems can be in the bottom or in the side wall of the metallurgical vessel, for example one Steel treatment pan. For Gas flushing systems are known in numerous embodiments.

Gas purging plugs usually consist of one Gas supply device, a gas distribution room, a ceramic flushing cone and, if applicable, one Sheet metal jacket. The installation of the Gas purging stones in a perforated brick in the refractory Lining, for example in the pan bottom or in one Sleeve, which in turn walled in the refractory lining or are stamped out. So that the sink during the Pan trip can be replaced from the outside usually a frusto-conical sink cone used, where the face with the smaller Diameter is directed towards the inside of the pan.

To increase the flow of gases through the sink allow, there are in principle different Embodiments. Changes in the Structure of the ceramic part made or it burn-out substances are added to the ceramic Or cause an increased porosity Ceramic insert is made with fine gaps or channels provided in an otherwise dense ceramic body or the gas is supplied through an annular gap between a dense ceramic cone and an enveloping one Sheet metal jacket. Combinations of different Embodiments are possible.

To fine gas bubbles to stir the molten metal generate, are embodiments of gas purging stones preferred, in which the ceramic insert made of porous made of refractory material or with fine channels has a small diameter or slits ("directed Porosity "). It is required that the sheet metal jacket over the entire circumference and its entire length lies evenly close to the ceramic insert. On Gas passage between the sheet metal jacket and the wall of the ceramic use should be avoided as far as possible. Even with one that progresses over time Wear the gas passage should be as defined as possible Distribution through the interior of the ceramic insert respectively. An uneven gas passage on the edge of the ceramic use should be avoided as far as possible.

DE 196 53 747 A1 discloses the sheet metal jacket by means of one installed in a hood furnace To heat induction coil and then on the shrink ceramic insert. The disadvantage is that putting the glowing sheet metal jacket on the ceramic use with excessive temperature differences lead to crack formation in the structure of the ceramic insert can. On the other hand, the temperature difference also not to be too small, since it shrinks securely of the sheet metal jacket on the ceramic insert should be guaranteed. DE 196 53 747 suggests this A1 before that in a hood furnace with induction coil Sheet metal jacket with the ceramic insert without contact Distance enveloped and heated by radiant heat. The merging of sheet metal jacket and ceramic Use should be immediately after the heating of the Sheet metal jacket.

Also in the method known from DE 40 21 259 A1 heating takes place in the interior of an inductor by means of inductive heating. It can only be heated inductively the outer jacket. The positioning of the ceramic Inside in the sheet metal jacket is done by means of a Lifting device.

The object of the invention is to overcome the disadvantages Shrinking a separately heated hot one Sheet metal jacket towards a colder ceramic insert avoid and in a simple process without inductive Heating of the sheet metal jacket and without mechanical niches Means for merging with the ceramic Use an even bond between the sheet metal jacket and ceramic use.

According to the invention, the object in a method of initially mentioned type in that first the refractory insert is pushed into the sheet metal jacket, the conical sheet metal jacket with the opening that the lesser Diameter down on a pad standing is heated from the outside, being more ceramic Insert and sheet metal jacket always remain in contact and that the heating takes place to such a high temperature that the ceramic insert solely because of its Weight force with expansion of the sheet metal sheath moves down to the compound position.

It has been found that there is no additional Forces required by means of a mechanical device to the ceramic insert in the sheet metal jacket Widening it. This is done alone under the influence of the weight of the ceramic Insert.

This ensures that the sheet metal jacket after the Cool down to a particularly even compressive stress exercises the ceramic insert. This is beneficial because so the sheet metal sheathing during use Gas flushing stone can support the refractory ceramics that Reduced susceptibility to cracking of the sink and therefore ensures that the purge gas only through the intended path the stone gets into the melt.

An advantageous embodiment of the method can characterized in that the sheet metal jacket with the ceramic insert inside during the Heating up a rotational movement around the vertical axis performs. By even rotation in one a defined distance from the heating device particularly uniform heating of the sheet metal jacket achieved. The heating device is expediently from a plurality of burner flames that span the height of the sheet metal jacket can be distributed. In addition, you can also burner flames over the circumference of the sheet metal jacket be distributed.

Fig. 1

zeigt in schematischer Ansicht die Vorrichtung.

Fig. 2

zeigt einen Längsschnitt durch die Anordnung von Drehteller, Blechmantel und darin eingesetztem keramischem Einsatz vor Beginn der Wärmebehandlung.

Fig. 3

zeigt im Längsschnitt den Zustand nach der Wärmebehandlung.

Fig. 4

zeigt ein Detail am unteren Ende des Spülsteins.

The device according to the invention is explained below using an exemplary embodiment.

Fig. 1

shows the device in a schematic view.

Fig. 2

shows a longitudinal section through the arrangement of the turntable, sheet metal jacket and ceramic insert used therein before the start of the heat treatment.

Fig. 3

shows in longitudinal section the state after the heat treatment.

Fig. 4

shows a detail at the bottom of the sink.

On the base plate of the work table (1) is in the View of Fig. 1 on the left about the vertical axis rotatable turntable (2) arranged. On the turntable (2) the conical composite element (7) stands vertically, the face with the smaller diameter after shows below. The composite element (7) consists of the Sheet metal jacket (8) and the ceramic insert (9). On the The work table (1) has a tripod (4) on the right. On the vertical stand rod is adjustable in height further rod (5) arranged horizontally. At this horizontal cross bar (5) is on the turntable (2) facing the end of a burner strip (3) attached. The Torch bar (3) can be adjusted using the side adjustment the crossbar (5) can be moved horizontally around the Set the distance to the turntable (2). Since she is at the Cross bar (5) via a joint (6) is attached she also in her inclination to the vertical be adapted to the cone of the composite element (7).

The fuel is supplied, for example as natural gas via the connection (3.1). On the composite element (7) facing side is the burner strip (3) with numerous gas outlet openings, one Variety of over the entire length of the burner strip (3) allow distributed burner flames (3.3). The The burner strip (3) can also be connected via the connection (3.2) be exposed to oxygen.

The conical ceramic insert (9) has, as in FIG. 2 shown the same taper as the sheet metal jacket (8). The ceramic insert (9) is shorter than that Sheet metal jacket (8) so that the ceramic insert (9) the sheet metal jacket (8) protrudes from both ends. The The face with the smaller diameter shows below towards the turntable (2). In the initial state before the Heat treatment is the face with the smaller one Diameter with distance "b 1" from the lower edge. At the top is the face with the larger diameter protrudes from the sheet metal jacket (8) at a distance "a 1". The Connection of ceramic insert (9) and sheet metal jacket (8) is done by gravity.

At the beginning of the manufacture of the composite element (7) the turntable (2) with the one standing on it Sheet metal jacket (8) in which the ceramic insert (9) is set in rotation. Then the Burner ignited. The burner flames (3.3) heat the Sheet metal jacket (8) evenly. The burner flame (3.3) must be set so that the sheet metal jacket (8) reached a uniformly high temperature to get under the influence of the weight of the ceramic Insert (9) to expand.

The ceramic insert (9) changes its position in the Composite element (7). The distance to the bottom decreases. 3 is the state after the Heat treatment of the sheet metal jacket (8) schematically shown. The distance from the lower edge "b 2" is now smaller than "b 1" before the heat treatment. In the same The distance "a 2" at the top edge is opposite "a 1" enlarged in the initial state.

Cooling begins immediately when the burner is switched off of the sheet metal jacket (8), which is then a compressive stress on the ceramic insert (9) exercises. Result of the The inventive method is a composite component, at which the sheet metal jacket (8) the ceramic insert (9) closely encloses and fixed in its position.

Characteristic for a according to the invention Process-produced composite component is the grooving at the lower edge of the rotary table (2) Sheet metal jacket (8), which is shown in Fig. 4. Below the ceramic insert (9) is the Sheet metal jacket (8) slightly inwards towards Center axis retracted. The difference "b 3" between that Radius at the point up to which the ceramic insert (9) is sufficient, and the radius at the bottom on which Rotary part (2) rising edge of the sheet metal jacket (8) is about 1.5 to 2%.

The usual design of the finished gas purging plug. Usually on the cone the larger diameter when used in the pan base or in the pan wall facing outwards, a bottom plate welded on, with a connecting piece for the Gas supply is provided.

Practical experience has shown that the temperature on which the sheet metal jacket, for example a stainless steel sheet, should be heated, is about 900 ° C. At a is a powerful burner Heating time of about 20 seconds as a more characteristic Value quite sufficient. If desired, can by Visual check to see if the heating is even. The ceramic insert then moves about 10 mm down. The expansion of the sheet metal jacket is 1%.

Claims (3)

1. A process for manufacturing a composite element out of a truncated cone shaped, fire-proof ceramic insert (9), which is enclosed by a metal jacket (8), characterized in that the fire-proof insert (9) is first inserted into the metal jacket (8), the conical metal jacket (8) standing on a base with the opening having the smaller diameter facing down is heated from outside, wherein the ceramic insert (9) and the metal jacket (8) always remain in contact, and the heating-up is performed up to a high temperature that the ceramic insert (9) shifts downward into the composite position solely under its own weight with the metal jacket (8) expanding.
2. The process according to claim 1, characterized in that the metal jacket (8) accommodating the ceramic insert (9) performs a motion of rotation around the vertical axis during the heating-up.
3. Apparatus for manufacturing a composite element out of a truncated cone shaped, fire-proof ceramic insert, which is enclosed by a metal jacket, for performing the process according to one of claims 1 or 2, characterized by a rotary plate (2), on which the metal jacket (8) with the ceramic insert (9) incorporated therein stands, with a burner strip (3) and means for adjusting the inclination of the burner strip (3) and the distance between the metal jacket (8) and burner flames (3.3).

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