DE2239059B2 - Metal mold for a centrifugal casting machine - Google Patents

Description

If the radial temperature gradient increases, the thermal stress on the outer jacket also increases forces acting on the locking wedges 4 through axial thermal expansion of the inner wall areas and the heat deformation of the whole metal mold. At high rotational speeds, there are considerable centrifugal forces in the liquid metal and the MetaUform even on the walls, so that the strength of the casting mold compared to a non-circumferential Form must be taken into account.

The in the F i g. The casting mold according to the invention shown in FIGS. 2 and 3 consists of an outer mold part 8 and an inner molded part 5. The inner metal molded part 5 has a flange 6 and at one end on its outer circumference a number of plastically deformable spacers 7, e.g. B. made of a copper alloy, of a certain height and size, which are arranged evenly distributed on its outer shell are. The inner molded part 5 is together with the spacers 7 in the outer molded part 8 ao inserted. Two cup-shaped lids 10 with a sand lining on their insides are on the Front ends of the inner molded part 5 fastened by locking wedges 11. The cover 10 are supported only on the outer molded part 8. The sand linings 9 attached to the covers 10 are on the inside Molding on.

In the case of a centrifugal casting process, the inner molded part 5 is heated up quickly. In the inner molding However, there is no high temperature gradient, since its wall thickness is relatively thin and he is thermally insulated from the outer metal molding 8. Its thermal expansion is not directly applied to the exterior Metal molding 8 transferred, but the spacers 7 between the inner and the outer Molded part compress and become deformed. The spacers can be used for multiple Use to be useful. Since the axial expansion of the inner metal molded part 5 at its free (in Fig. 2 right) end is caught by one of the sand linings 9, which is on the locking wedges 11 force exerted is considerably reduced. Although the temperature of the outer molding 8 increases because heat from the inner molded part 5 is deformed by its thermal expansion Spacer 7 is transferred to the outer molded part, but the temperature gradient of the outer Molded part 8 only low and the thermal stress effective in it small because the heat from the liquid Metal is not transferred directly to it. The thermal expansion of the inner molded part 5 is shown in Limited to a certain extent by the outer molded part 8. As a result, an additional one acts in the outer molded part Tensile stress, which can lead to the breakage of the outer molded part 8. Hence the distance should between the inner and the outer metal molded part 5 and 8 are chosen so that the entire Stress is less than with the conventional one-piece metal casting mold. The appropriate ones Distances can be determined by practical measurement and by theoretical calculation, as indicated in the following table:

Example A.
(mm) Example B.
(mm) Example C
(mm) Outside diameter of the outer molded part 1950 1700 1380 Inner diameter of the outer molded part 1580 1280 1050 Outside diameter of the inner molding 1578 1278.4 1048.6 Inner diameter of the inner molding 1300 900 800 Difference between the inside diameter of the
outer molding and the outer diameter of the
inner molding not less
as 2 not less
than 1.6 not less
than 1.4

When using the inventions, at least 100 mm and diameters of at least

proper mold even when casting large at least 800 mm of very good quality and without

Castings only low vibration of the casting mold and cracking even after more than 50 casting runs

only slight heat deformations 50 are produced in the same mold after casting,
on. Large pipes with wall thicknesses of

1 sheet of drawings

Claims (2)

to be able to accommodate the coil springs, what . Patent claims: inevitably to a certain instability or to Vi Brations in high-speed rotating molds , 1. Double-walled metal mold for sluice can lead. The cooling systems also provide a i die casting machines, in which an internal measuring 5 represents considerable technical effort. tall molded part in an outer metal molded part In another double-walled centrifugal casting through several deformable spacers under form (CH-PS 114 221) is the cylindrical intermediate training a cylindrical space between the inner shell and the outer holding is and in which the front ends of the ring mold with a liquid at operating temperatures deckein are completed, which at their inner ι «· material, z. B. lead, of high thermal conductivity have a sand lining so that it is filled. This is intended to relieve the rods characterized in that the outer mold with good heat conduction at the same time Stand holder (7) between the inner and that of the inner shell to the outside can be reached, outer molded part (5 or 8) made from plastic Made of metal. 15 unsuitable temperatures of more than 400 ° C. 2. Chill mold according to claim 1, characterized in that the object of the invention is to provide a metal casting, that the front ends of the inner measurement form of the type mentioned are created, in which a vertical flow form (5) to the sand lining (9) the equally low temperature gradient and EntDeckel apply correspondingly smaller thermal stresses within the so moldings can occur, so that the mechanical Stresses on the rotating moldings are reduced. In the solution according to the invention, the unfilled cylindrical space between the 35 inner and outer mold part represent an insulating space through which the temperature gradient of the internal The invention relates to a double-walled metal ^interior ? Mold part in the radial direction substantially mold for centrifugal casting machines with the Merk- is reduced. This gap has darmalen of Gattungsbeiriffes still emenAusgleichseffekt of claim 1. ^Moreover, the radial So far could only columnar ³ ° heat and Fl.ehkraftdehnung of mnerenKokillenförmige castings of small diameter and ^te by centrifugal casting! ^le * '^ ^durc _u ^{h dl} ^ at operating temperatures ^ pla hollow cylinder with relatively thin wall thickness, a her- ^tical property that is uniformly placed on the outside. Since in these cases the heat ^{retention area of the inner} mold part arranged Abder castings is smaller than the heat-absorbing stand holder expansion of the inner mold or molded part and castings. Therefore, one-piece molds for ^{making thin-walled or small castings by their} widening during the deformation could produce intimate contact with the outer molded part. can be used without any problems. ^{For the} operation of centrifugal casting is a In the manufacture of thick-walled rotational body * ° such intimate contact between the outer and or of large-diameter pipes according to the Schleudergießver- ^de m inner mold part of significance insofar as it can drive due to the large heat content by both mold parts as quasi Uniform cord of liquid metal, the resulting stretchers, and vibrations or other dangerous voltages and the high centrifugal forces to fertilize are prevented. The insulating effect of the groove fractures and / or vibrations and shocks +5 cylindrical space is therefore mainly caused by the centrifugal casting machine. To be limited to the short period of time immediately after the casting due to the high temperatures triggered by the melt. Thermal expansion of the mold in controllable The following is a known, one-piece To keep limits, double-walled casting mold centrifugal casting mold and one according to the invention men or molds developed. With such a 5 <> Mold design on the basis of the drawing in the known centrifugal casting machine (DT-AS 1108 862) individually described. It shows the revolving molding device consists of a fig. 1 is a longitudinal section through a known Inner mold and an outer reinforcement jacket, one-piece metal mold for centrifugal casting,
which forms the carrier for the mold and on rollers F i g. 2 runs a longitudinal section through the mold. Between the tubular inner mold and 55 measured the invention, the reinforcement jacket are elastically deformed. 3 shows an enlarged partial section through the bare, designed as toroidal coil springs, in FIG. 2 shown metal mold,
spacers at mutual axial distances The in F i g. Known casting mold 1 shown in FIG intended. To reduce thermal degradation, it has a protective coating on its inner jacket Formations of the inner mold is the spacing 6 ° and at their ends a pair of cup-shaped covers 3, Holder-receiving cylindrical interspace between each of which has a sand lining attached to it the inner shell and the reinforcement jacket 2 carries and on the mold by closure with acted upon by a coolant. This cooling wedges 4 is attached. The internal temperature of the metal leads however, to an extraordinarily high heat-form after potting, depending on the type and shape gradient within the inner shell and too large 65 of the thickness of the protective coating rise above 400 ° C, thermal internal stresses of the mold mate- The wall thickness of the metal mold is usually entrials. In addition, the cylindrical intermediate must correspond to the heat content of the space to be cast have a significant radial distance, designed objects. Since with greater wall thickness