WO2012159898A1

WO2012159898A1 - Casting method for permanent moulds

Info

Publication number: WO2012159898A1
Application number: PCT/EP2012/058703
Authority: WO
Inventors: Hans Mikota; Markus Bühringer; Werner Menk
Original assignee: Georg Fischer Automobilguss Gmbh
Priority date: 2011-05-24
Filing date: 2012-05-11
Publication date: 2012-11-29
Also published as: EP2527060A1

Abstract

The invention relates to a novel permanent mould casting method with which the cycle time can be significantly reduced. Furthermore, a casting mould for carrying out the method is proposed.

Description

Casting method for permanent molds

The present invention relates to a casting method with permanent molds according to the preamble of claim 1 and a casting apparatus according to the

Preamble of claim 4.

The glazing in metallic permanent molds is known that solidification conditions with rapid heat removal can be achieved by the solidification of the liquid metal in a metal mold. Metallic permanent molds have in the

Unlike the sand molds used in sand casting, the advantage of much higher thermal conductivity. This can be a higher

Solidification velocity, finer microstructure (smaller so-called DAS - dendrite arm distances) and thus shorter cycle times (number of produced

Castings per unit time) can be achieved.

The solidification in sand molds proceeds more slowly, whereby the formation of the microstructure matrix in sand molds is coarser (higher DAS) and lower mechanical properties are achievable compared to mold casting. Metallic permanent molds (such as chill molds) are thus very well suited for the glazing of heavy-duty castings such as chassis components, since the fast cooling conditions (for example in aluminum chill casting) allow very fine microstructures to be achieved. In particular, the edge shells (i.e.

first solidified areas of castings, which are in direct contact with the

Metal mold stand) by particularly fine microstructure. To maintain a rapid heat dissipation during the entire solidification is to strive for the expression of a fine microstructure. However, this can not be achieved in the current state of the art in Kokillenguss- or die-casting. When Glessen in permanent molds, the heat dissipation of the solidifying metal over several phase boundaries takes place. The heat must be from the solidifying component away over several, partly heat-insulating layers (eg heat-insulating

Plain, air gap) are transported through the mold.

Equation 1 describes the heat flow per unit time over these phase boundaries.

Equation 1: Q point = k ^* A ^* AT [W]

Q point: heat flow per unit time [W]

k total heat transfer coefficient [W / m ^{2 *} K]

A heat exchanger surface [m ² ]

AT ... temperature difference [K]

In order to improve the heat dissipation are known in the art

various measures possible:

A Enlarging the heat exchanger surface

e.g. Cooling ribs on the mold outer wall AT Increasing the temperature difference between the cooling medium and the component e.g. Ice water instead of water for heat dissipation

The heat transfer coefficient is, depending on the structure of the permanent form of several individual resistors assembled, which limit the heat transfer. The decisive factor is always the greatest single resistance, which is the

Total resistance determined.

Equation 2: 1 / k = 1 / a1 + s / λ + 1 / a2 cd: Heat transfer coefficient for the heat transfer from the casting to the permanent form

For example, in order to maximize cd, chill casting attempts to use thermally conductive sizing or to minimize the air gap when solidified by high feed pressures.

Thermal resistance through the mold wall of a permanent mold. The mold wall is made of a material with the specific thermal conductivity λ [W / m ^* K] and has the wall thickness s [m]

To minimize this resistance was tried better

to use thermally conductive tool materials or to reduce the wall thickness of these materials.

Heat transfer coefficient for heat transfer from

Formaussenwand on the cooling medium

In order to improve the heat transfer on the mold outer wall water cooling circuits were used.

After the formation of a solid peripheral shell, the volume contraction of the solidifying metal comes into play. The solidified metal is no longer in contact with the mold wall, an air gap is formed. The heat transfer coefficient between the casting and the metallic permanent mold drops sharply, slowing down the solidification. This slowed-down heat removal leads to a coarser formation of the microstructure in the solidifying metal, resulting in poorer mechanical properties. The formation of the heat-insulating gap between casting and permanent mold can not be prevented by the current state of the art.

In order to keep the solidification speed higher, strong ones can be used

Cooling can be used to reduce the temperature of the permanent mold and to keep the heat flow high through a strong temperature gradient between the casting and the mold. However, these complex but effective cooling measures have the disadvantage that the temperature of the permanent mold for the next filling is lowered too much. To avoid filling errors (such as cold runs) must the

Therefore, the tool temperature must be raised again before the next casting: this requires the use of a burner or requires tempering measures, for example via heating / cooling units. The additional, energetically unfavorable effort reduces the efficiency of the casting process and extends the cycle time. In order to accelerate the cycle time and the complete cooling of the cast pieces produced, it is known to partially open permanent molds after complete through-solidification of the cast parts produced and to apply a cooling medium to the cast parts produced at the exposed locations (JP 2009 2551 18 A or JP 10 005966 A ). In contrast, JP 57 109559 A uses an additional heat sink provided especially for this purpose, which is partially demoulded and cooled. In another known variant (JP 2007 270195 A) solidified castings are cooled at different speeds. Again, after Dauererstarrung the cast part, the Dauerform partially opened. The permanent portion of the casting continues to cool slowly, while the exposed portion of the casting remains cool

Casting air-cooled and thus hardened.

This above-mentioned method has its disadvantage in common: the additional cooling only starts after complete solidification, i. that I

Intermediate structure is coarse and their mechanical

Properties in need of improvement. The provision of a special heat sink (JP 57 109559 A) is also consuming and v.a. not economical.

A special variant of sand casting is described in the literature under the name "ablation" and is published, for example, in WO 2004/026504 A1 or WO 2004/004948 A2, which is a sand casting method, more specifically a core package method through several sand cores leading to a core package to be assembled.

After filling the Sandkernpaketform with liquid metal is the

Edge shell formation due to the heat transfer of the liquid metal to the sand mold. Once a self-supporting edge shell has formed, the core shape can be resolved by a jet of water. During and after the rinsing of the core sand from the already partially solidified casting follows the initially slow edge shell solidification by heat transfer casting on the sand mold a phase fast solidification progress in the interior of the component. This is caused by the strong cooling effect of the water jet applied directly to the surface of the solidifying component.

The products produced by this process are characterized by a coarse structure on the outer skin of the component that becomes finer on the inside.

A disadvantage of the ablation-casting process is the initial - in

Comparison to die casting - slower edge shell solidification and thus the coarser texture near the surface. On the surface of the component, this method thus achieves the structure typical for sand casting processes. Thanks to the ablation-casting process, it is only in the interior of the component that the high material properties achievable by direct cooling can be achieved. However, this is disadvantageous, in particular in the case of component applications which are subject to static and dynamic strength, because here, in most cases, the peripheral fibers or

Edge regions of the components are subjected to the highest static and dynamic load and thus require the best solidification conditions and lowest DAS with the best mechanical properties.

Another disadvantage is the relatively worse

Economics of the ablation process due to the complex production of the required molds. Each individual component of the core package is to be produced via a core to be produced in a core shooting process. Furthermore, these individual cores must be laboriously assembled to the core package before each casting.

Furthermore, the core package is destroyed during casting by flushing with water and can only be used once. The core sand is after unpacking with water only in poorly processed further form of turbidity. The sand can thus, in contrast to the widespread dry coring processes in the ablation process only after consuming and energy-intensive

Reprocessing processes are returned to the casting process.

Other disadvantages of the Ablationsgiessverfahrens exist in the classic, also known from other Sandgiessverfahren weaknesses: The

Surface quality of the components produced in the ablation process is limited by the fineness (or coarseness) of the sand used and in the

Generally worse than when using metallic permanent molds. The geometrical dimensional accuracy of the components produced in the ablation process is compared to the mold casting by the dimensional accuracy of the

Casting process preceding processes at a disadvantage. Inaccuracies in the

Core shooting, core distortion during storage of the cores and process-related

Inaccuracy in the subsequent joining of the cores to a core package lead to a poor dimensional stability of the products produced in comparison to conventional die casting or die casting. Semi-continuous casting processes are also used for the production of semi-finished products such as continuous cast ingots or sheets. A widely used process variant of continuous casting is known as direct chili casting process. This (semi-) continuous casting process is characterized by excellent material properties. As with the ablation process, a phase of very rapid heat removal follows here on the edge shell solidification due to the direct effect of the water jet on the surface of the solidifying layer

Aluminum. However, in contrast to the ablation process, the first phase of continuous casting, i. the solidification and the formation of the

Edge shell, characterized by very fast cooling conditions, since the liquid metal is in direct contact with a metal mold and thus the

Edge fibers are strongly cooled. A disadvantage of the continuous casting process or the direct chilli casting process is that it has so far been available only as a (semi) continuous casting process for the production of semi-finished products such as bolts, profiles, sheets or slabs. The production of geometrically complex components from materials produced with Direct Chili Casting is so far only through subsequent joining processes

(Welding, gluing, mounting) and forming processes (for example, forging process) possible and correspondingly very expensive.

The present invention is therefore based on the object to improve the cooling process during molding with permanent molds such that higher

Freezing speeds are made possible, which on the one hand significantly reduces the cycle time and on the other hand, castings can be made with a finer microstructure. This object is achieved by the casting method according to the invention and its features listed in claim 1. To solve the problem, a casting device and a permanent mold according to the further independent claims is preferably used. According to the prior art, a permanent mold is made up of at least two molded parts. Non-demoulding undercut areas of components can be realized via additional attached to the mold movable slides or sand cores. According to the well-known casting process, the phase of mold filling is followed by a phase of very good heat removal by wetting the permanent mold with liquid metal. As soon as a solid edge shell of solidified metal has formed, a phase of lower heat transport sets in, since the edge shell separates from the permanent shape due to the volume contraction and a heat-insulating air gap is formed, which causes rapid solidification with the disadvantages described above for the

Component quality (coarser matrix) and cost-effectiveness (long cycle time) prevented. The casting method according to the invention, however, makes use of the effect of the formation of a rim shell: after local formation of a

Edge shell on the casting, the corresponding mold segment is lifted from the component and partially demolded. Simultaneous with local demolding, direct cooling of the exposed component surface via cooling media, such as e.g. by directly sprayed water, water spray or by flooding the entire exposed area with cooling medium.

According to the solidification progress further mold segments can be removed from the mold locally to the exposed edge shell of the component directly

To cool cooling medium and to accelerate the solidification. This results in a significant cycle time reduction and improvement of the

mechanical properties realized thanks to the accelerated solidification (finer structure).

Another advantage is the fact that the formation of a

heat-insulating air gap between the cooling medium and casting is actually pre-empted. For the first time in the process of glazing with permanent molds, the negative effects of the insulating air gap between the casting and the permanent mold can be eliminated on the heat dissipation.

In order to use the method according to the invention, the permanent form is divided into several movable segments. This division is not used

necessarily the formation of undercut areas on the component, but this does not exclude.

According to the invention can be achieved by accelerating the solidification a significant cycle time reduction and increase in productivity. Furthermore, due to the partial demolding and subsequent direct cooling of the

Cast surface The insulating effect of molding materials between cooling medium and solidifying casting. The above-mentioned Equation 2 is thus simplified to Equation 3.

Equation 3: 1 / k = 1 / a3

The total heat transfer coefficient k is thus only more dependent on a3 (heat transfer coefficient cast on the cooling medium). Two of the formerly three individual resistors are 0 and thus no longer affect the heat flow.

At the beginning of solidification, the solidification rate can be maintained even for the phase of edge shell formation by the use of permanent metal molds instead of sand molds. Thus finer structures can be achieved in the edge shell area than in the case of processes which use sand molds

(especially during the ablation process in the sand casting process). Furthermore, as already mentioned, a better dimensional stability is achieved by the use of a segmented permanent mold than with sand casting.

Likewise, in contrast to the ablation process in the sand casting process, the time-consuming production process for the preforms (cores) and the processing of the waste sludge are eliminated.

According to the invention, several cooling systems are conceivable and possible for the cooling design: Both open-type cooling systems, e.g. operated in the evaporator mode, as well as closed cooling circuits, e.g. with flooding of the exposed casting surface. The inventive cooling design can be designed such that the cooling device with the cooling medium first forms a closed cooling circuit as a mold cooling device and the cooling medium is applied directly to the partially exposed Gußstückoberfläche at full or partial moving away a Kokillensegmentes, it can be an open cooling (the cooling medium is washed away or evaporated) or one more

closed cooling is formed (the exposed casting surface is flooded, but the cooling medium can not drain and continues to form a closed cooling circuit with the cooling medium inflow and outflow.

In the following, the invention and its mode of action will be explained in more detail with reference to figures and a schematic embodiment.

The casting method for permanent molds according to the invention will first be explained by means of an example with the schematic figures 1 to 10. The permanent mold from which the mold is shaped, according to the invention consists of several mold segments. In the present example, the permanent form consists of three shape segments. In the figure 1, the two mold halves 1 and 2 are shown (upper mold part 1 and the lower mold part 2), wherein the upper mold part 1 according to the invention still comprises the mold segment 4 in contrast to conventional permanent mold halves. Of course, in a real implementation of the invention, the permanent mold may consist of 4 or more mold segments.

For example, it is quite conceivable that the upper mold part 1 consists of more than 2 mold segments or that the lower mold part 2 more

Permanent shape segments has.

Are the two half-molds 1 and 2 (including the associated

Kokillensegmente) closed, the actual mold or cavity 5 is formed in which the liquid metal is to solidify into a casting.

As usual in a casting process, follows the process step of

Closing of the mold (FIG. 1) the filling of the casting mold or cavity 5 shown in FIG. 2 with a molten metal (shown in a wavy hatching). Immediately after or simultaneously with the filling of the casting mold 5 with the molten metal, cooling 3 of the permanent mold segments can be switched on.

The individual Kokillenkühlungen can all at the same time or, as from the

Transition from Figure 2 to Figure 3 recognizable, are switched on sequentially. As also shown schematically in FIG. 3, the liquid metal begins by the inevitably occurring heat transfer or heat removal from solidify the liquid molten metal on the mold or permanent mold. The first areas of solidifying metal arise in the areas of the mold with a large surface to volume ratio, since in these areas the heat dissipation is greatest. Typically, these are thin-walled areas of the casting or of the subsequent casting. In a casting mold, the metal usually also initially solidifies on the outer edge of the casting mold, while the inner region initially remains liquid or soft. Thus, so-called first edge shells 6 are formed, or the process step of edge shell formation begins (see marginal shell 6 in FIG. 3). Even if the solidification process thanks to the usually made of metal

Permanent forms (good heat transfer and thus -abfuhr) is already favored, the solidification process and thus the edge shell formation by the

Use of one or more Kokillenkühlungen 3 are of course much faster.

Essential for the method according to the invention are the steps now shown in FIGS. 4 and following:

As soon as areas with a solid edge shell of solidified metal form in the casting mold, a local partial demolding of the casting mold takes place in these areas. For this purpose, the permanent mold segment 4 is removed from the mold, so that the solidified edge shell 6 is exposed (see Figure 4). Simultaneously with this local demolding, or (immediately) thereafter, the exposed casting surface is treated directly with a cooling medium, e.g. Water (directly

sprayed, as water spray or by flooding the entire exposed area with the cooling medium), cooled (see Figure 5). This component cooling is shown schematically in FIG. 5 by the reference numeral 7. As cooling media, of course, other liquids can be used. Also, an injection with air, another gas or the use of a

Gas mixture as a cooling medium would be conceivable (however, the use of a gaseous cooling medium is less efficient than a liquid

Cooling medium).

In the figure 6, the much faster cooling and solidification of resulting casting thanks to the inventive cooling method by the growing marginal shell 6 schematically indicated. Of course, the cooling process according to the invention is also further supported by the mold cooling 3 which preferably continues to operate in this process stage.

The cooling process according to the invention is preferably continued until edge shells have formed around the entire casting 8 (FIG. 7). The aforementioned Kokillenkühlung 3 can from a certain time in

Solidification process of the casting also prematurely turned off (see Figure 7 with mold cooling 3 out of service, while the direct component cooling 7 is still in operation). This can be particularly advantageous if it can be prevented that the permanent mold halves or permanent mold segments cool down too much. An additional heating process in preparation for the next casting process can be avoided in whole or in part.

Once edge shells have formed around the entire casting 8 and the casting 8 is self-supporting (i.e., no longer deformed), the

Permanent mold halves open (see Figure 8) and the casting 8 are removed (see Figure 9). The casting process is completed and can begin anew for the production of another casting (see Figure 10).

In the other figures 1 1 to 21 are different, especially for the

Application of the inventive casting process developed permanent molds shown. These are of particular suitability for the implementation of the casting method according to the invention and enable the efficient implementation or

Realization of the inventive idea.

FIGS. 11 and 12 show a first variant of a permanent mold specially developed for the implementation of the casting method according to the invention. The permanent mold shown in these figures is represented by 2 permanent mold segments 9 and 9 ^'. (Segment 9 ^' is not shown) and two slides 10 and 1 1 formed. These parts together form the cavity or mold 5. The slide 10 is a cooled slide, ie it has a built-in cooling device 12. This

Cooling device consists in the present example of several cooling channels 13, 14. The cooling channel 14 forms the coolant flow, the two outer cooling channels

13 the coolant drain. The cooling channels of the cooling device 12 in the slide 10 are configured in the present embodiment such that the cooling channel

14 are connected to the two cooling channels 13 via the short connection channels 15 in the slide 1 1. The openings of the cooling channels 13 and 14 are arranged in alignment with the openings of the two connecting channels 15 so that they - as shown in Figure 1 1 - in the state of a closed mold (closed permanent mold segments or slide) together form a positive, dense cooling circuit.

In a further, not shown variant, the short connecting channels 15 contained in the slide 1 1 is dispensed with. Instead, the slider 10 may be in contact with the second slider 11

Surface have one or more grooves. These grooves would be in

closed state (both slide) with the in contact

Surface of the slide 1 form 1 form-fitting, dense channels and thus take over the function of the short connection channels 15, i. connect the cooling channel 14 with the other cooling channels 13. Through this simplified

By design, the manufacturing costs of the slider 1 1 can be reduced. In the cooling circuit can be used as a cooling medium, for example, water, oil or a water-oil mixture. Of course, the cooling circuit of the cooling device 12 with an external (not shown here)

Heat exchanger connected.

Of course, the illustration in FIG. 11 shows the cooling device 12 only schematically. It is therefore quite conceivable that a plurality of cooling channels 14 are provided for the coolant flow and above all a plurality of cooling channels 13 for the coolant outflow. Thus, the coolant channels, for example, evenly distributed for optimum cooling below the surface of the slider 10 in Be arranged portion of the cavity 5.

Analogous to the preceding figures and as is usual in a casting process, the mold cavity 5 is initially filled with liquid metal (shown hatched in FIGS. 11 and 12) for the casting process. Immediately after or at most simultaneously with the filling of the casting mold 5 with the molten metal, the cooling device 12 of the slide 10

be switched, which - as shown in Figure 1 1 - forms a closed cooling circuit. The switched on cooling device 12 causes increased heat dissipation, so that the liquid metal in the region of the cooled slide 10 solidifies faster and thus relatively quickly forms a region with a solid edge shell of solidified metal. Once this formed peripheral shell around the slider 10 is stable enough, the slider can be partially moved away from the hitherto closed state, i. be partially demolded (see Figure 12). By this Teilentformung an area with a solid peripheral shell of the casting surface is exposed and now according to the present invention directly with the

Cooling medium 21 of the cooling device 12 - e.g. Water - applied, i. the demolded area or the exposed casting surface is flooded directly with the cooling medium.

During this process step according to the invention of the partial demolding and simultaneous flooding, the closed cooling circuit of the cooling device 12 preferably still remains in operation, of course. This is shown in FIG. 12

schematically represented by the arrows on the cooling channels 13 and 14 of the cooling device 12 of the slider 10.

Due to the direct loading of the casting with the cooling medium, the solidification process according to the invention is substantially accelerated. This results in the above-mentioned better microstructural properties in the cast component and a considerable cycle time reduction (higher productivity of the casting device). Figures 13 and 14 show a further variant of a specially for the

Implementation of the inventive casting process developed Dauerform. The operation and operation of the permanent mold shown in these figures is up to two differences analogous to the permanent mold of Figures 1 1 and 12: In Figures 13 and 14, the slider 16 on the one hand during the

it is provided with integrated nozzle openings 25 for the application of a cooling medium 21 to the casting surface. On the other hand, the cooling circuit in the permanent variant of Figures 13 and 14 is open and not closed.

The permanent mold is formed here essentially by the two permanent mold segments 17 and the slide 16, which define the cavity or casting mold 5. The slider 16 has integrated cooling channels 18, which may be configured, for example, as simple holes. The cooling channels are pressurized via an external - not shown - device with a suitable cooling medium under pressure. The permanent mold is in the closed state, so are the openings 25 of the cooling channels 18 which are located on the surface of the slide 16, positively sealed by the permanent mold segments 17. That in the closed state of the permanent mold according to FIG. 13, no cooling medium flows and there is no additional cooling through the

Cooling channels 18 instead.

Also in the casting process with this second variant of the permanent mold according to the invention, the cavity 5 formed in a form-fitting manner is first filled with liquid metal (shown hatched in FIGS. 13 and 14). As soon as the

Solidification process has progressed far enough that has formed a solid edge shell made of solidified metal in the mold in the area around the slide 16 and this trained edge shell is stable enough around the slider 16, the slider 16 can partially moved away from the previously closed state and the Mold are partially demoulded with a fixed peripheral shell (see Figure 14). By this Teilentformung the previously closed openings 25 of

Cooling channels 18 exposed in the slide 16 and the cooling medium 21 contained therein under pressure can escape. The cooling channels 18 with the openings 25 are arranged in such a way that the cooling medium 21 exiting, for example as a spray jet or spray mist, impinges on the exposed casting surface (see schematic representation in Figure 14) and thus the latter immediately cooled, thereby significantly accelerating the solidification process. In contrast to the permanent mold in the two preceding figures, this second variant of the permanent mold according to the invention has no closed cooling circuit but an open cooling circuit. That is to say, the cooling medium 21 in FIG. 14 exits, possibly evaporates partially and has to be removed. The cooling device shown by the two cooling channels 18 in this second variant also does not work as long as the permanent mold is shot, because the openings 25 are positively closed in this state.

An advantage of this second variant of the permanent mold according to the invention is its simpler construction method and, in particular, that its cooling circuit is open and uses it virtually automatically during part removal.

In a sub-variant of this second permanent mold according to the invention, the cooling channels 18 are not bores in the slide 16, but rather as holes

Hose connections (for example made of metal) executed, the outlet openings are preferably closed in a form-fitting manner, as long as the permanent mold is closed. The provision of hose connections instead of holes in the slide 16 allows u.a. a more favorable production of the permanent mold and a lighter orientation of the exiting cooling medium jet 21 at the openings 25th

Even with the second variant results in a direct loading of the casting with the cooling medium 21st This results in the aforementioned better structural properties in the cast component and a significant cycle time reduction (higher productivity of the casting apparatus).

Of course, combinations of the two variants of the permanent mold according to the invention just described are also conceivable. Thus, e.g. of the

Slider 16 of the second variant shown in Figures 13 and 14 have an additional cooling circuit, which forms a closed cooling circuit, as long as the permanent mold is closed or the openings 18th

are positively locked. For this one would have in slide 16 only an additional (not shown) connection or bore between the Provide cooling channels 18, as well as one of the two cooling channels 18 as Kühlmediumzu- and convert the other as Kühlmediumabfluss. When the slide 16 is moved away from the closed position, the cooling medium exits in the manner described above and cools the exposed casting surface in an open cooling circuit, while the additionally provided connection or bore in the slide 16 becomes ineffective.

FIGS. 15 and 16 show a further variant of a permanent mold according to the invention. Here are easily by moving away of the

Slider 19, the openings 25 of the cooling channels 20 sequentially -. depending on the position of the slide 19 - put into operation. This may be advantageous if one wants to control the cooling effect exerted on the casting over the amount of the exiting cooling medium 21. By providing many cooling channels 20 with corresponding openings 25 in the permanent mold segments 1, 2, the casting to be cooled is also better wetted with the cooling medium 21 or

sprayed.

Figures 17 to 21 show the typical process steps, which with the inventive casting method and a novel

Be passed through casting or permanent mold. In the cited figures, for example, a mold casting apparatus is shown. FIG. 17 shows the permanent mold consisting essentially of two permanent mold segments 17 and a slide 22 in the closed state. The slider 22 has inter alia a temperature sensor 23 which serves to determine the surface temperature in the adjacent region of the casting mold 5. The temperature sensor 23 is metrologically connected to a controller 24 which cooperates with a mechanism (not shown) for removing the slider 22. In particular, the controller 24 is intended to partially or completely move the slider 22 partially or completely out of the closed state as a function of the surface temperature of the casting-piece surface produced in the cavity 5, as a function of the surface temperature produced by the temperature sensor 23 move away and so release a part of the Gusstückoberfläche for direct cooling medium loading.

In the device according to FIGS. 17 to 21, the slide 22 also has a cooling device 12 with a closed cooling circuit, which functions analogously to the above description of the cooling device of FIG. However, the cooling circuit of the cooling device 12 in Figures 17 to 21 remains closed at all times, so that the cooling medium used therein never comes into direct contact with the casting surface.

The casting device according to the invention of FIGS. 17 to 21 has in its two permanent mold segments 17 and in the slide 22 cooling channels 20 which function analogously to the embodiment of FIGS. 15 and 16. The cooling channels 20 may - but need not - already be filled with a pressurized cooling medium in the state of the closed permanent mold. If the permanent mold is in the aforementioned closed state, then the outlet openings 25 of the cooling channels 20 are closed in a form-fitting manner, as in the preceding examples.

In the casting apparatus shown in Figs. 17 to 21, by moving the slider 22, cooling channels 20 are sequentially - i.e., analogously to the embodiment of Figs. depending on the position of the slide 22 - released and put into operation. As a result, it is possible to control the cooling effect exerted on the casting mold 5 via the number of released cooling passages 20 or via the quantity of the cooling medium 21 emerging thereby. In the closed state of the permanent mold according to FIG. 17, the liquid metal is filled in the cavity 5 in a conventional manner as a first method step. The actual mold filling process of the permanent mold with liquid metal is state of the art and takes place as in the preceding examples. Thanks to the temperature sensor 23 and the associated controller 24, however, it is possible here to measure the complete filling of the cavity 5 with liquid metal as an increase in temperature and thus to confirm that the temperature measured by the temperature sensor 23 exceeds a minimum temperature

Tvoii, (see arrow in the controller 24 of Fig. 17) so this may be from the controller 24 as proof of the complete filling of the mold 5. In the second, shown in Figure 18, process step is started with the forced cooling of the melt in the cavity 5: The cooling device 12 of the slider 22 is put into operation and the temperature profile of the present in the cavity 5 melt is via the temperature sensor 23 and measured and controlled by the controller 24 (see arrow in the controller 24 of FIG. 18).

Thanks to the provided cooling device 12, the melt or the metal in the cavity 5 cools relatively quickly. If the measured temperature falls below a predetermined value T _En tform - as shown in Figure 19 - so gives the

Control 24 of the slide actuator or the mechanism for moving the slider 22 in a second method step, the signal to pull the slider 22. The value T _En tform must in this case naturally corresponding to a temperature range, can be provided in which that a sufficiently stable edge shell has formed for the partial removal from the mold of the casting behind the direct casting surface. With the moving away of the slide 22, not only a part of the casting surface is exposed, but also the openings 25 of the cooling channels 20. If the cooling channels 20 are filled with a cooling medium under pressure, the cooling medium occurs simultaneously with the

Exposing the openings and thus directly cools the exposed casting surface. According to the illustrated casting apparatus it is

in principle possible to release the openings of the cooling channels 20 sequentially and thereby gradually increase the cooling effect. Of course, the cooling channels 20 need not be filled with a cooling medium all the time and be under pressure. It is also conceivable that the cooling channels 20 are empty in the first method step and are flooded only with the second method step according to FIG 19 with an externally supplied cooling medium for the purpose of cooling the exposed casting surface. The controller 24 may be designed accordingly.

The following figure 20 already shows a third process step, in which the temperature measured by means of sensor 23 (see arrow in the control 24) at the Surface of the slider 22 has _fallen below a certain value T _min . If the controller 24 determines that this value T _{min is} undershot, it takes the cooling device 12 of the slide 22 out of operation. By this measure, it is prevented that the slider 22 cools down too much. If, for example, continuous-form segments are cooled too much, mold-filling problems or casting defects can occur during the next casting process. However, while the cooling device 12 is turned off, the casting is still cooled directly with the cooling medium 21. The cooling circuit of the cooling medium 21 is open here, ie the

Cooling medium 21 runs out of the casting device and must - what is not evaporated - are dissipated.

FIG. 21 shows the last method step: If the casting has cooled sufficiently and thus solidifies, the further charge of the casting with the cooling medium 21 can be turned off from the cooling channels 20. The two permanent mold segments 17 can be opened and the casting removed. The casting device is thus ready for a new casting process.

It should be pointed out that the aforementioned control 24 of the casting device according to the invention according to FIGS. 17 to 21 can also be made simpler. So it would be e.g. conceivable the

Omit temperature sensor 23 and the device or controller 24 only time-dependent control based on previously determined values.

It should also be explicitly stated at this point that the

previously described slide also permanent form segments.

The present invention therefore comprises a casting method with or for

Permanent molds. These may be in particular metallic or ceramic permanent molds for the glazing of metal. Preferably, the

Casting according to the invention used in mold or die casting. The casting mold is made from one or more

Formed permanent shape segments. The casting method according to the invention has following steps:

- Close the continuous form segments

Filling the permanent mold with liquid metal,

- After formation of a region with a solid edge shell made of solidified metal, a Teilentformung the resulting casting in the fixed area

Edge shell by removal of one or more permanent shape segments

- And that the exposed portion of the casting surface is applied with a fixed edge shell with a cooling medium.

Preferably, for the coolant admission to water or a

Used spray of water and air. The cooling medium impingement can also be done by flooding the entire exposed casting surface with the cooling medium, thereby accelerating the solidification process of the casting. According to the casting method according to the invention with or for permanent molds, further permanent mold segments can be locally removed from the mold according to the solidification progress. The thus additionally exposed, solid edge shells of the casting can also be acted upon by the cooling medium to further accelerate the solidification process of the casting.

In a possible embodiment of the invention, individual

Permanent mold segments - in particular so-called slides - have a cooling device. According to the inventive method they are

Cooling devices after filling the permanent mold or its cavity turned on with liquid metal.

If several cooling devices are provided, they can be used individually or

be switched on sequentially. Preferably, the cooling devices of those Dauerformsegmente be switched on first, which in a later

Step moved or should be removed (so-called slide). In addition to the casting method, the invention also includes a casting device which is suitable for the application of the casting method. For this purpose, a plurality of permanent mold segments forming a casting mold are used. The

According to the invention, the casting apparatus has a mechanism for removing individual permanent mold segments or slides, which serve for local premature demolding of solidified casting mold areas.

These permanent mold segments or sliders, which can be removed by the mechanism or slider actuator system, can have one or more

Have temperature sensors for determining the surface temperature in the mold.

Preferably, the slider or permanent mold segment, which is removable by the mechanism, has its own cooling device. In this cooling device is preferably used as a cooling medium water, oil or a water-oil Geschmisch.

Particularly preferred, in addition to the slider and others

Dauerformsegmente cooling devices, which preferably also use as a cooling medium water, oil or a water-oil Geschmisch.

In a preferred embodiment, the casting apparatus may also include a controller which controls the mechanism for removing individual

Continuous shape segments controls.

Thus, this control, for example, the mechanism or the actuators for the removal of individual Dauerformsegmente (slider) as a function of a measured surface temperature or time-dependent control. In addition to the casting method, the casting device also includes a permanent mold according to the invention, which is essentially formed from at least two permanent mold segments forming the permanent mold. In at least one of the permanent mold segments, preferably a so-called slider, a

Cooling device provided. Among other things, this can consist of one or more cooling channels assigned to the permanent mold segment or integrated therein for the transport of a cooling medium. Preferably, the openings of these cooling channels are arranged such that they are positively and thus close in the closed state, as long as the Dauerformsegmente or the slide with the other

Permanent mold segments are in the closed and permanent forming state and that the openings of these cooling channels are exposed as soon as one of the permanent mold segments or the slide from the closed

Condition is moved.

Preferably, the cooling channels in the permanent mold segment or introduced in the slider holes. In this case, the openings of these cooling channels can be so on the surface of the permanent mold segment or the slider

be arranged that with exposed opening and pressurized

Charging the cooling channels with a cooling medium that conveys cooling medium towards the casting surface or cavity, e.g. is sprayed on.

The cooling channels can also be located on or in the surface of the

Dauerformsegmentes introduced lines, preferably hoses, or

Grooves are formed. The openings of these lines can in this case be arranged on the surface of the permanent mold segment such that, with the opening exposed and pressurized transport of a cooling medium in the lines or grooves, the cooling medium is conveyed in the direction of the casting or cavity for the purpose of direct cooling.

Structurally, it can also be provided that, when partially lifting one of the permanent mold segments or the slide, the openings of the cooling channels are exposed on the permanent mold segment surface or slide and the area of the casting surface thus exposed is directly flooded with the cooling medium. In this case, both a closed and an open cooling circuit can be formed.

The cooling device in the slide or in the permanent mold segments consists of at least two cooling channels. This is certainly a cooling channel as Kühlmedium- inflow and certainly a cooling channel as a cooling medium outflow. The cooling channels may be arranged such that when the permanent mold segments or the

Slider with the other permanent mold segments in positively closed and the permanent mold forming state, said cooling channels in or on the permanent mold segments form a closed cooling circuit.

Another variant of the inventive casting method is the

Use of one or more so-called "lost mold segments" instead of the individual permanent mold segments to be removed. "Lost mold segments are preferably sand casting segments

Area with fixed marginal shell of solidified metal the so-called "lost

Mold segment "at this point simply washed away with the cooling medium.

This gives a particularly simple casting device, because this requires no special mechanism for the removal of individual

Permanent mold segments as in the aforementioned variants of the invention. The premature, local partial removal occurs simply by flushing away the (lost) mold segments to be removed. In contrast to the ablation process, where the entire sand mold is washed away, however, it can continue to be used here

Permanent molds are worked.

The present invention is not limited to those explicitly described

Limited embodiments. These variants are intended rather as a suggestion for the expert to implement the idea of the invention as low as possible. From the described embodiments, therefore, further advantageous applications and combinations are readily derivable, which also reflect the inventive concept and should be protected by the following claims. Legend

1 permanent mold half, mold top

2 permanent mold half, lower mold part

3 cooling, chill cooling

4 mold segment, permanent mold segment, mold segment

5 cavity, mold

6 marginal shell

7 Direct component or casting cooling

8 cast

9 permanent shape segment

10 cooled slide

1 1 slider

12 cooler slider

13 Cooling channel for the coolant outflow

14 Cooling channel for the coolant inflow

15 connecting channel

16 slides with integrated coolant inflow or nozzle openings

17 permanent shape segment

18 cooling channel

19 pushers

20 cooling channel

21 cooling medium

22 slides

23 temperature sensor

24 control

25 openings

Claims

claims

1 . Casting method for permanent molds, in particular metallic or ceramic permanent molds, for the glazing of metal, preferably by the mold or die casting method, into one of a plurality of permanent mold segments (1, 2, 4, 9, 10,

1 1, 16, 17, 19, 22) formed casting mold (5), wherein the casting method comprises the following steps:

Closing the permanent mold segments (1, 2, 4, 9, 10, 11, 16, 17, 19, 22)

Filling the permanent mold with liquid metal,

characterized in that

immediately after the formation of a region having a solid peripheral shell (6) made of solidified metal, a partial removal of the resulting and partly still liquid or soft casting (8) in the area with a fixed peripheral shell (6) by removal of one or more permanent-mold segments (4, 10, 16, 19, 22) happens

and that the exposed area of the casting surface is firmer

Peripheral shell (6) is acted upon with a cooling medium (21), wherein for this purpose preferably water or a spray of water and air is used, and wherein the cooling medium loading is particularly preferably done by flooding the entire exposed casting surface with the cooling medium,

to accelerate the solidification process of the casting.

2. casting method with permanent molds for the glazing of metal according to claim 1, characterized in that according to the solidification progress further permanent mold segments are removed from the mold locally,

and that the additionally exposed solid edge shells of the component are also acted upon by the cooling medium to the

Solidification process of the casting to further accelerate.

3. casting method with permanent molds for the glazing of metal according to claim 1 or 2, characterized in that individual Dauerfornnsegnnente (4, 10, 22) a cooling device (3, 12), which after filling the

Permanent form be turned on with liquid metal.

Casting method with permanent molds for the glazing of metal according to claim 3, characterized in that

the cooling devices (12, 20) of individual continuous-form segments (2, 19, 22) are switched on sequentially, wherein preferably the cooling devices of those permanent-form segments are first switched on, which are to be removed in a later method step.

Casting device suitable for the application of a casting method according to one of the preceding method claims, comprising a plurality of permanent mold segments forming a casting mold (1, 2, 4, 9, 10, 11, 16, 17, 19, 22), characterized in that the casting device has a mechanism for removing individual Dauerformsegmente (4, 10, 16, 19, 22) for local premature demolding of solidified casting sections.

Casting device according to claim 5, characterized in that the

Permanent mold segment (4, 10, 16, 19, 22), which is removable by the mechanism, temperature sensors (23) for determining the

Surface temperature in the region of the mold (5).

Casting device according to claim 5 or 6, characterized in that the permanent mold segment (4, 10, 16, 19, 22), which is removable by the mechanism, has its own cooling device (3, 12), preferably in the cooling device (3 , 12) used as a cooling medium (21) water, oil or a water-oil Geschmisch. Casting device according to claim 5, characterized in that the permanent mold segments (4, 10, 16, 19, 22) cooling devices (3, 12, 18) preferably, water, oil or a water-oil mixture is used as the cooling medium (21).

9. Casting device according to one of claims 5 to 7, characterized

in that the casting device has a control (24) which controls the mechanism for removing individual permanent mold segments (4, 10, 16, 19, 22).

10. Casting device according to claim 9, characterized in that the

Control (24) the mechanism for removing individual

Permanent shape segments (4, 10, 16, 19, 22) depending on a measured surface temperature or time-dependent controls.

1 1 .Dauernform for use in a casting device or with a

A permanent mold casting method according to one of the preceding claims, comprising at least two permanent mold segments (1, 2, 4, 9, 10, 11, 16, 17, 19, 22) forming the permanent mold, characterized in that

at least one of the continuous shape segments (1, 4, 10, 11, 16, 19, 22) has one or more associated ones, preferably integrated in the duration segment,

Cooling channels (3,13, 14, 15, 18, 20) for the transport of a cooling medium (21),

wherein the openings (25) of the cooling channels (13, 14, 15, 18, 20) are arranged such that they are positively in the closed state, as long as the Dauerformsegmente (10, 1 1, 16, 19, 22) in the closed and the permanent form forming state and that the openings (25) of this

Cooling channels (13, 14, 15, 18, 20) are exposed as soon as one of

Permanent mold segments (10, 1 1, 16, 19, 22) is moved from the closed state. 12. permanent mold according to claim 1 1, characterized in that the

Cooling channels (13, 14, 15, 18, 20) introduced in Dauerformsegment bores represent and that the openings (25) of these cooling channels (13, 14, 15, 18, 20) are arranged on the surface of the Dauerformsegmentes (10, 1 1, 16, 19, 22) that with an exposed opening (25) and pressurized transport of a cooling medium (21) in the exposed cooling channels (13, 14, 15, 18, 20), a cooling medium in the direction of casting or cavity (5) is conveyed.

13.Dauerform according to any one of claims 1 1 or 12, characterized in that the cooling channels are formed by introduced on or in the surface of the permanent mold segment lines, preferably hoses, or grooves and in that the openings of these lines on the surface of the

Dauerformsegmentes are arranged, that when exposed opening and pressurized transport of a cooling medium in the lines or grooves, the cooling medium is conveyed in the direction of casting or cavity. 14. permanent mold according to one of claims 1 1 to 13, characterized in that when partially lifting a Dauerformsegmentes (10) the openings (25) of the cooling channels (13, 14, 18, 20) are exposed on the Dauerformsegmentoberfläche and thereby exposed thereby Field of

Casting surface with the cooling medium (21) is flooded directly, thereby forming a closed or an open cooling circuit.

15. permanent mold according to one of claims 1 1 to 14, characterized in that the permanent mold segments (10) at least two cooling channels (13, 14), wherein at least one cooling channel (14) as a cooling medium inflow and at least one cooling channel (13) as Cooling medium drain serves, and the

Cooling channels (13, 14, 15) are arranged such that when the

Permanent mold segments (9, 1 1, 10) are in the positively closed and forming the permanent shape state, said cooling channels (13, 14, 15) in or in the permanent mold segments (10) form a closed cooling circuit (12).

.Gießverfahren according to one of claims 1 to 4 or casting device according to one of claims 5 to 10, characterized in that

the permanent mold segments to be removed are replaced by lost mold segments, preferably sand casting segments, and the partial demoulding takes place by flushing away these lost mold segments with the cooling medium (21).