Method for producing a cast component with an insert

Abstract

A method for producing a cast component may include providing an insert part including an insert body having a circumferential face; coating the circumferential face with an adapter layer made of silicon oxide; arranging the insert part in a casting mold; and positively locking a casting encapsulation of the insert part and the adapter layer with an aluminum alloy to produce the cast component, wherein the aluminum alloy has a magnesium proportion of at least 0.3% by weight.

Claims

1. A method for producing a cast component, comprising: a) providing an insert part including an insert body having a circumferential face; b) coating the circumferential face with an adapter layer made of silicon oxide, wherein coating the circumferential face with the adapter layer includes: dipping the insert body into a solution comprising a water glass; and curing the water glass to form a silicon oxide via heating the insert body; c) arranging the insert part in a casting mold; and d) positively locking a casting encapsulation of the insert part and the adapter layer with an aluminum alloy to produce the cast component, wherein the aluminum alloy has a magnesium proportion of at least 0.3% by weight.

2. The method as claimed in claim 1, wherein: the insert part is a cylinder liner and the cast component is a cylinder block for an internal combustion engine.

3. The method as claimed in claim 1, wherein the water glass comprises Na.sub.2O.sub.3Si.

4. The method as claimed in claim 1, wherein curing the water glass to form the silicon oxide further includes heating the insert body to a temperature of 400 C. or higher.

5. The method as claimed in claim 4, wherein the water glass comprises Na.sub.2O.sub.3Si.

6. The method as claimed in claim 1, wherein the magnesium proportion of the aluminum alloy is at least 0.5% by weight.

7. The method as claimed in claim 1, wherein the insert part is a piston ring carrier and the cast component is a piston for an internal combustion engine.

8. A method for producing a cast component, comprising: providing an insert part including an insert body having a circumferential face; coating the circumferential face with an adapter layer made of silicon oxide, wherein coating the circumferential face includes: applying a silicone resin to the circumferential face; and curing the silicone resin to form a silicon oxide via heating the insert body; arranging the insert part in a casting mold; and positively locking a casting encapsulation of the insert part and the adapter layer with an aluminum alloy to produce the cast component, wherein the aluminum alloy has a magnesium proportion of at least 0.3% by weight.

9. The method as claimed in claim 8, wherein the magnesium proportion of the aluminum alloy is at least 0.5% by weight.

10. The method as claimed in claim 9, further comprising diluting the silicone resin with a solvent before applying the silicone resin to the circumferential face.

11. The method as claimed in claim 8, wherein the silicone resin has a layer thickness of 5 m to 10 m before curing the silicone resin.

12. The method as claimed in claim 8, wherein coating the circumferential face further includes diluting the silicone resin with a solvent before applying the silicone resin to the circumferential face.

13. The method as claimed in claim 8, further comprising diluting the silicone resin with a solvent before applying the silicone resin to the circumferential face.

14. The method as claimed in claim 8, wherein curing the silicone resin to form a silicon oxide via heating the insert body includes heating the insert body to a temperature of 400 C. or higher.

15. The method as claimed in claim 8, wherein the insert part is a cylinder liner and the cast component is a cylinder block for an internal combustion engine.

16. The method as claimed in claim 8, wherein the insert part is a piston ring carrier and the cast component is a piston for an internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, in each case diagrammatically:

(2) FIG. 1 shows a cylinder liner which is coated with silicon oxide before being inserted into a casting mold in order to produce a cylinder block,

(3) FIG. 2 shows a cylinder liner which is encapsulated by casting in a casting mold with an aluminum alloy and forms a cylinder block together with the aluminum alloy, and

(4) FIG. 3 shows a ring carrier which is encapsulated by casting with an aluminum alloy and forms a piston together with the aluminum alloy.

DETAILED DESCRIPTION

(5) In each case in a roughly diagrammatic longitudinal section, FIGS. 1 and 2 illustrate the method according to the invention for producing a cast component 6 in the form of a cylinder block. FIG. 1 shows an insert part 1 in the form of a cylinder liner which has an insert body which has a circumferential face 3 and is called a liner body 2 in the exemplary scenario of FIGS. 1 and 2. As shown in FIG. 1, the liner body 2 can be of sleeve-like configuration. Before the liner body 2 is introduced into a casting mold (not shown in FIG. 1), its circumferential face 3 is coated with a layer of silicon oxide, called an adapter layer 4 in the following text.

(6) According to a first variant, the application of an adapter layer 4 of this type takes place in two method steps: in a first step, a silicone resin is applied to the regions of the circumferential face 3 which are to be encapsulated by casting. In a second step, the silicone resin is cured to form silicon oxide by way of heating of the liner body 2. In order to transform the organic silicone resin into silicon oxide, the liner body 2 can be heated to a temperature of 400 C. or more, for example with the aid of a suitable furnace. It is true here in general that a low layer thickness aids a rapid curing process, which has an advantageous effect on the industrial manufacture of the cylinder liner in large numbers. Particularly satisfactory results during the oxidation of the silicone resin are achieved if the silicone resin which is applied to the circumferential face 3 has a layer thickness of from 5 to 10 m before the curing to form silicon oxide. To this end, the silicone resin can be diluted by means of a solvent before the application to the circumferential face 3.

(7) According to a second variant which is an alternative to the first variant, the application of the adapter layer 4 takes place by way of dipping of the cylinder liner into a solution of water glass. Here, all water-soluble sodium, potassium and silicon silicates which have solidified from a melt are covered by the term water glass, in particular also Na.sub.2O.sub.3Si. Said silicates have glass-like, that is to say amorphous material properties. After dipping of the cylinder liner into a water glass solution of this type, the cylinder liner is dehydrated, that is to say cured, in an analogous manner to the first variant which is described in the preceding text, by way of heating of the cylinder liner, preferably to a temperature of 400 C. or more in order that predominantly silicon oxide remains.

(8) The cylinder liner which is coated with silicon oxide in accordance with the two above-described variants can then be inserted into a casting mold 5 which is shown diagrammatically in FIG. 2. Finally, the cylinder liner is encapsulated by casting in a positively locking manner with an aluminum alloy 7 which completes the cylinder liner with respect to a cylinder block, said aluminum alloy 7 having a magnesium proportion of at least 0.3% by weight, preferably of at least 0.5% by weight. The adapter layer 4 of silicon oxide which is applied on the circumferential face 3 of the liner body causes the aluminum alloy 7 which is introduced into the casting mold 5 by means of aluminum high pressure die casting to exhibit an improved wetting behavior during casting encapsulation of the cylinder liner if the aluminum alloy 7 has a magnesium proportion of at least 0.3% by weight, preferably of at least 0.5% by weight. As a consequence, a particularly satisfactory positively locking connection is achieved between the cylinder liner and the aluminum alloy 7, which connection in turn ensures a pronounced heat transfer between said two components. The cured silicon oxide of the adapter layer can react in the region of the boundary surface to the aluminum alloy with the magnesium which is contained in the aluminum alloy in accordance with the reaction equation SiO.sub.2+2 Mg.fwdarw.2 MgO+Si, as a result of which the wetting of the surface can be improved decisively.

(9) As a further, second exemplary application for the method according to the invention, FIG. 3 then shows a cast component 6 which is produced by means of the method according to the invention in the form of a piston for an internal combustion engine, in a roughly diagrammatic longitudinal section.

(10) FIG. 3 shows an insert part which is denoted by 1 in the form of a piston ring carrier which has an insert body which has a circumferential face 3 and is denoted as ring carrier body 2 in the exemplary scenario of FIG. 3. Before the ring carrier body 2 is introduced into a casting mold (not shown in FIG. 3) for casting encapsulation with an aluminum alloy 7, its circumferential face 3 is coated with a layer of silicon oxide, in the following text called an adapter layer 4 in an analogous manner to the example of FIGS. 1 and 2.

(11) The above explanations with respect to the exemplary scenario of FIGS. 1 and 2 apply mutatis mutandis to the application of the adapter layer 4 on the circumferential face; that is to say, in order to produce a piston in accordance with a first variant, first of all a silicone resin is applied to the regions of the circumferential face 3 which are to be encapsulated by casting, and said silicone resin is oxidized to form silicon oxide by way of subsequent heating of the ring carrier body 2. According to a second variant, the application of the adapter layer 4 takes place by way of dipping of the piston ring carrier into a solution of water glass. After the dipping of the piston ring carrier into a water glass solution of this type, the latter is once again cured to form silicon oxide by way of heating of the piston ring carrier.

(12) The piston ring carrier which is coated with silicon oxide in accordance with the two described variants is subsequently inserted into a suitable casting mold and is encapsulated in a positively locking manner by casting with an aluminum alloy 7 in said casting mold, which aluminum alloy 7 then completes the piston ring carrier 1 with respect to the piston, said aluminum alloy 7 having a magnesium proportion of at least 0.3% by weight, preferably of at least 0.5% by weight. The adapter layer 4 of silicon oxide which is applied on the circumferential face 3 of the ring carrier body 2 causes, in an analogous way to the example of FIGS. 1 and 2, the aluminum alloy 7 which is introduced into the casting mold by means of aluminum continuous casting to exhibit an improved wetting behavior during casting encapsulation of the piston ring carrier if the aluminum alloy 7 has a magnesium proportion of at least 0.3% by weight, preferably of at least 0.5% by weight. As a consequence, a particularly satisfactory positively locking connection of the piston ring carrier and the aluminum alloy 7 is achieved which in turn ensures a pronounced heat transfer between said two components.