DE2319208C3 - Apparatus and method for casting composite cast rolls - Google Patents

Description

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The invention relates to the casting of composite cast rolls made from a hard shell material and a soft core material.

By the German patent 17 58 526 is already one Device known in which the mold from a lower box forming the lower roll neck with a roller chill resting on it and an inserted into it, forming the upper roller journal Molded part, with the lower box laterally in the tangential cut the pouring pipe (funnel pipe) opens and wherein the lower box has a slide at the bottom, through which the still liquid, remaining Co Jacket material is drained into a pouring ladle, after which with the slide closed by the Funnel tube the core material is filled.

This has the advantage that the excess, high-quality jacket material remains completely separated from the core material, which is subsequently refilled, and does not as with other methods, it is degraded by mixing at the interface so that it is separated collected and can be used again immediately without reprocessing except for post-heating. In addition, the slide that is used allows unhindered draining of the jacket material and then perfect closing the form.

Practice has now shown that when casting extremely large (long and thick rolls) z. B. from Heavy plate rolling according to this method has difficulties in that it takes time for drainage of the excess sheath material and the filling of the core material in this case proportionally is long, so that there is no longer a sufficient bond between the cladding layer and the core under uniforms It is guaranteed that the draining and filling process can be accelerated, for example by enlarging the openings in the slide, for reasons of casting technology (see below) large flowing mass) and on the whole not justifiable for reasons of economic operation. Another disadvantage is that the entire casting device by the longer roller and the lower The collecting pan located in the casting mold reaches a very large overall height

So far one saw in such cases prompted such rolls by the overflow method z. B. according to the German patent 4,77,287, in which the excess jacket material is flushed out of the casting mold upwards by the core material, which is filled in from below through the funnel tube. The disadvantage of this method is that a relatively large amount of core material must be flushed through until it is mixed with the Sheath material the desired composition of the core material is achieved. This is e.g. B. at It is necessary to manufacture high-chromium-hall rollers, in which the chromium has to be largely removed from the core material.

It is also already known from German Patent 6 56 221 to cast composite cast rolls in a mold, the lower box of which is provided with a stopper is provided, which is actuated with a stopper rod penetrating the entire shape. It will after the desired jacket layer has solidified, the remaining jacket material that has not yet solidified through Open the stopper and let it go downwards and from above onto the jacket material underneath simultaneous automatic sinking soft core material filled up, however, the drained jacket material does not flow freely into a pouring ladle, but in a bucket located under the lower box, which after pulling out the stopper rod the Form seals downwards. The disadvantage here is that the drained jacket material solidifies and does not can be used further without further ado, there are many ways to work with a stopper rod Reasons very disadvantageous.

The invention has set itself the task of eliminating the disadvantages of the known methods and to create a device and a method that also for the casting of large rolls, in particular whose heavy plate rolls are suitable

It is based on the device and the method according to the German patent 17 58 526 from which the excess sheath material is in a ladle is drained.

The device according to the invention consists in that a teapot-like siphon is attached to the slide.

is closed, the outflow cross-section is variable

When the slide valve is open, the siphon keeps the outflow velocity of the jacket material constant held and reduced so far by the choice of appropriate outflow cross-sections that in Inside the form a slow and steady fall of the metal level occurs without any signs of turbulence

This enables the separate, complete drainage of the excess jacket material to avoid and to carry out the method according to the invention according to the German patent 17 58 526 so that in a manner known per se on the casing material sinking in the casting mold steadily from Core material is filled up above, with almost no mixing compounds in the separation zone occur more between the two materials.

The drained jacket material is recovered in the liquid state in a pouring ladle placed under the siphon, the particular advantage being that this no longer adversely affects the height of the pouring device due to its height

Another embodiment of the invention is that the height of the siphon is the length of the rollers or the mold is adapted in such a way that the distance of the upper edge of the siphon neck from the The upper edge of the casting mold is constant for all rollers by changing the length of the siphon standpipe is held. This means that when the jacket material is drained, rolls of various lengths are used Constant pressure conditions are created, which also result in constant outflow conditions.

The invention also consists in that a further slide is arranged behind the slide, which as an alternative or always to complete the mold after the excess jacket material has been drained off serves

The second slide ensures that the mold can be closed in any case, even if the first slide is due to the high ferrostatic pressure - Formliöhe z. B. 10 m - and possible solidification of material between the movable slide parts result in malfunctions should.

S The drawing shows a schematic representation of an embodiment of a casting device according to the invention.

It denotes 1 the roll coke with the molded part 2 forming the upper roll neck. 3 is the

ίο lower roll neck forming lower box, which on the drain stand 4 rests. The funnel tube 5 through which the jacket material opens laterally in the lower chamber is poured into the mold.

At the bottom of the lower box 3 is the following lined drain block 10 and then the also following lined slide 11, the is operated by a hydraulic cylinder.

The teapot-like siphon 12 is arranged next to the slide 11, which extends upwards.

ao stretches and its downwardly directed outflow end with an outflow stone 13 of certain cross-section is provided. Of course, the entire neck of the siphon can also have one instead of the outflow stone have reduced cross-section. The top of the

»5 siphon neck is made by changing the length of the siphon standpipe held at a certain distance 15 from the upper edge of the molded part 2. Between the slide 11 and the siphon 12 can also have a further slide (not shown) arranged

to be used as an emergency slide or, in principle, always to shut off the mold after the jacket material has been drained serves.

The pouring ladle 14 is located under the mouth of the siphon to catch the excess jacket

j5 material.

16 is the pouring ladle, with the liquid core material from above on the slowly sinking down Mirror of the through the open. Slider 11 and the siphon 12 draining jacket material continuously refilled is, the interface 17 between the two materials remains completely at rest.

1 sheet of drawings

Claims (4)

Patent claims: 1. Device for casting composite cast rolls, especially of extremely large composite cast roll with a hard shell material and a soft core material consisting of a the lower case forming the lower roll neck, a roll chill resting on it and an in these inserted, the upper roll neck forming part, with the side in the lower box the pouring pipe in the tangential cut (Funnel tube) for the casting material opens and the lower box at the bottom with a Slider is provided and placed on a drainage block, characterized in that on the slide (11) is connected to a teapot-like siphon (12), the outflow cross-section of which is variable 2. Device according to claim 1, characterized marked ao shows that the distance (15) of the upper edge of the siphon neck from the upper edge of the casting mold is kept constant by changing the length of the siphon standpipe for all rollers. 3. Device according to claim t and 2, characterized as that behind the slide (U) still another slide is arranged, the auxiliary or always to complete the mold after Drainage of the excess jacket material is used 4. A method for casting composite cast rolls with a device according to claims 1 to 3, characterized in that in a known manner with the slide (11) closed through the pouring tube (5), the roller shape with jacket material is filled, then after the desired jacket thickness has solidified, the slide (ti) is opened and the still liquid, remaining part of the alumina material is drained via the siphon (12) into the pouring ladle (14), in a manner known per se The shell material, which sinks into the casting mold, is continuously filled up with the core material from above will.