DE1558292A1 - Method for producing a press plate from cast iron with cast-in steel tubes - Google Patents

Description

1558292 Andrejewslei & Honke patent attorneys

Physicist

Dr. Walter Andrejewski

«- * ■. ·. ~~ η / graduate engineer

Lawyer file: 2? 899 / mra. _Dr _ _{| ng Manfred Ho ||| w}

Essen, September 3, 1969 Kettwiger Strasse 36 Patent application Siempelkamp Foundry K.G. K r e f e 1 d, Benrader Strasse 45

Method for producing a press plate from cast iron with cast-in steel tubes

The invention relates to a method for producing a heatable and / or coolable press plate made of cast iron Cast steel pipes to form channels for the heating and / or coolant.

Cast press plates with cast steel tubes are known in vulcanizing presses. The panels are merely heated and have a relatively large plate thickness of 100 mm and more in order to ensure that they keep the heat as long as possible during the vulcanization process. To the

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BADORIGiMAL 009812/0717

Patent attorneys Dr. W. Andrejewski, Dr. M. Honlce, 43 Es $ en, Ketrwiger StraBe 36

Casting such "thick" press plates, the steel pipes are first sandblasted outside the mold to their surface to be cleaned, pickled if necessary, and then inserted into the mold. The mold filling time during the casting process is because of the large Plate thickness correspondingly long, so that there is enough time available stands so that the steel pipes can set themselves in temperature equilibrium with the cast iron, which causes the cast iron to dance The surface film on the pipe surface can be broken down and the temperature movements of the steel pipes can subside, before the cast iron begins to solidify. As a result, the steel pipes connect perfectly with the cast iron can. In order to avoid impairment of the pipe cross-section under the usually occurring welding through of the pipe wall to report, the pipes are tightly filled with quartz sand in the sense of a casting core. This is the temperature compensation between the steel pipes and the cast iron is not affected.

Presses * are particularly important for the production of Kunetoff panels Multi-daylight presses are known whose press plates are heated and cooled in rapid succession of temperatures are, for which the plates also have channels through which a heating and a coolant are passed alternately. Such plates must therefore have the lowest possible thermal inertia and are therefore as thin as possible, at most in a thickness of 60 mm. The production of such "thin" press plates with inserted steel pipes by casting however, presents particular difficulties which have hitherto prevented the casting of "thin" press plates. That's how it is

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009812/0717

Patent attorneys Dr. W. Andrejewski, Dr. M. Honke, 43 Essen, Kettwiger Strasse

Pouring "thin" press plates the mold filling time is very short (5 to 8 see.) »The casting solidifies accordingly quickly. In this short time, the steel pipes can meet the required Do not perform temperature equalization so that the pipes still work while the casting is solidifying, in addition, the surface film on the pipes will not removed in a sufficient way, all of which leads to a poor connection between the pipe and cast plate as a result.

Incidentally, a method of casting around is tubular, in particular Body that is bent several times or has a small internal width and is made of metal with the same or higher melting point known as passing gases or liquids through the pipe, gas or liquid under controllable back pressure is passed through the pipe, which approximates the deformation resistance of the pipe at its expansion temperature holds the scales. Furthermore, one has for the production of finned tubes, in particular for feed water preheaters and pre-evaporators, Measures are implemented, according to which the dissipation of the heat absorbed by the casting as required by using more or less good heat conductor regulated as a filler and the steel pipe is preheated before casting. - These known ones Processes move to a different field of technology and have the problems of producing "thin" heating and / or coolable press plates made of cast iron with cast-in steel pipes were not significantly influenced.

The invention is based on the object of a method of the above called type in such a way that the casting is "thinner"

0098 12/07 17

Patent attorneys Dr. W, Andrefewski, Dr. M. Honke, 43 Essen, Kettwiger Strasse

Press plates with cast steel tubes without occurrence the disadvantages described is possible.

This object is achieved according to the invention in that the steel pipes, after being inserted into the casting mold, are heated to temperatures above 150 ⁰ 0 , then poured around them and immediately thereafter cooled from the inside by means of a gas stream. The heating of the steel pipes before casting can take place electrically by means of an electric current passed through the pipe wall or by means of a heating gas passed through the pipes. In a preferred embodiment, the steel tubes are pressed into an oval cross-section before casting and arranged with the larger cross-sectional axis in the direction of the plane of the press plate.

By stringing together these two process stages, the invention achieves a thoroughly surprising effect. In fact, it has been shown that heating the pipes to at least 150 ° C. before casting is sufficient to remove surface films on the pipes to be poured which are harmful to the pouring process and which have always been a problem within the framework of known measures. As a result of the cooling that starts immediately after the pipes have been poured around the pipe, the inner surfaces of the pipes are kept at a relatively low temperature, which does not prevent the pipes from welding on the outside of the pipe to the Gußelsen, but on the whole apparently the temperature of the pipe during the entire pouring and solidification process Cast iron holds so largely that the bond between pipe and cast iron impairing thermal movements of the pipe can no longer occur. 3o show according to the method according to the invention

BATH ORIGINAL

0 0 9812/0717

Patent Attorneys Or. Wo Androjewski, Dr ₉ Mo Henke, 43 Ess @ m _; SC®ttwig @ r street

Elimination of disruptive surface films and etosYes avoidance

between pipe and plate, whereby DurohschweSn the pipe no longer occurs due to its cooling from the inside. The structure of the cast is very finely crystalline in the area of the pipe surface, which is an advantage because the GnS stays in place due to this fine structure, even if the pipe wall should self-destruct. In addition _, the thermal conductivity of such a structure is better than that of a coarsely crystalline structure, so that, as a result, when the method according to the invention is implemented, the thermal conductivity of the press plate produced is also improved. ·

The advantages achieved by the invention are % ahlv® ± ®fo _a On the one hand, the "thorn" press plates produced by the method according to the invention - with a considerably large channel cross-section and very small channel spacing compared to the plate Mioke - can be made. This not only results in a very even temperature distribution over the flat surface, but also enables the production of press plates with a very low mass compared to the volume and the surface, the duct system and therefore very little heat transfer, so that short heating and cooling times for the press plate © can be achieved. In addition, extremely thin plates, especially with an oval shaped cross-section of the steel tubes, can be produced. In the case of the press plate produced according to the invention, the tubes can run in any desired guidance over the plate surface and can be rounded off, especially in the deflection points, see above

0098 12/0717

Patent attorneys Dr. W. Andrejewski, Dr. M. Honke, 43 Essen, Kettwiger Strasse

that sharp edges and the signs of wear that tend to occur thereon are avoided. In addition, there is the possibility of providing the pipes at least in the curves of the pipe run made of stainless steel, which further contributes to reducing wear. Finally, the casting material itself in the area of the pipe walls is very wear-resistant due to its fine crystalline structure due to the cooling of the pipes during the pouring process, so that the plate can continue to be used if the pipe wall itself should be worn away in places. In addition, cast iron shows a much better temperature change behavior than steel and, under strong local temperature differences, which ^{are unavoidable in the temperature play between heating and cooling in "thin 1} 'press plates, tends to form far less than steel.

In the following the invention is explained in more detail with reference to an embodiment shown in the drawing; the only Figure shows a detail of a cross section through a press plate produced according to the invention.

The press plate 1 shown in the figure consists of cast iron with steel pipes 2 cast therein to form channels 3 for a heating and / or coolant, with the help of which the plate as a whole can be heated or cooled. Before casting, the steel pipes 2 are heated to temperatures after being placed in a casting mold heated above 130 ° C, then without prior cooling encapsulated and immediately afterwards from the inside by means of a gas stream chilled. The heating of the steel pipes 2 before casting can be

BATH ORIGINAL 009812/0717

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0098 12/0717

Claims (1)

Patent attorneys Dr. W. Andrejewski, Dr. M. Honke, 43 Essen, Kettwiger Strasse - 8 claims 1 «Process for producing a heatable and / or coolable Press plate made of cast iron with cast-in steel tubes to form channels for the heating and / or coolant, characterized ^ that the steel pipes after insertion in the cast iron mold is heated to temperatures above 150 ° C, then poured over and. immediately thereafter cooled from the inside by means of a gas stream will. 2, method according to claim 1, characterized in that the Steel pipes in the form of electric cables by means of a gas flow be cooled. 3. The method according to claim 1 and 2, characterized in that the steel pipes are pressed into an oval cross-section prior to casting and with the larger cross-sectional axis in the direction of the plane of the press plate be placed in the mold. PAe Dr Andrejewski, Dr Honke Inferior (Art. 7 § 1 Ats. 2 \ _r 1 ^ - _ä ■ BATH ORIGINAL 009812/0717