DE3436846A1 - Die-casting process for light metals and alloys thereof - Google Patents

Abstract

The invention relates to a die-casting process for light metals and alloys thereof, which is used above all in the manufacture of die-castings of aluminium, aluminium alloys and zinc. <??>It is the aim and object of the invention to improve the execution of the die-casting process by the provision of homogeneous, firmly adhering release agent layers of low residue on the working surfaces of the die-casting moulds and, at the same time, to provide the preconditions for automation. <??>According to the invention, the object is achieved by applying to the working surfaces of the die-casting moulds a mould-release agent which consists of a combination of aqueous solutions or dispersions of at least one carboxylate of metals from main group I of the Periodic Table of the Elements and at least one carboxylate of metals from main group II of the Periodic Table of the Elements, or of zinc and a system of dihydric and trihydric alcohols.

Description

a) Title of the invention

Die casting process for light metals and their alloys

b) Field of application of the invention

The invention relates to a die-casting process for light metals and their alloys, which is mainly used in the Manufacture of die-cast parts from aluminum, aluminum ' alloys and zinc is used

c) Characteristics of the known technical solutions In the die-casting process, molten light metals or their alloys are processed into corresponding die-cast parts using die-casting machines.One of the most critical process stages is the separation of the molded parts from the die-casting mold.Therefore, it is necessary to insert the molten metal in Treat the die-casting mold with a mold release agent to prevent the casting material from sticking and to ensure that the die-cast parts can be removed from the mold.

In the relevant literature, a number of methods are described in which for the treatment of the Die casting molds solid, pasty or liquid release agent combinations are used · Liquid release agents are used because of their favorable application possibilities preferred"

The separating substances used are mainly graphite, molybdenum or tungsten disulfide, metal powder, etc. which in the corresponding 'carrier media such as oils and Water or their mixtures and the like are incorporated. However, there are not inconsiderable problems here the homogeneous distribution of the separating substances in the carrier medium the production of stable release agent dispersions

There has therefore been no lack of attempts to address this disadvantage to eliminate · Among other things, such release agent combinations Metal salts of aliphatic carboxylic acids and also polyhydric alcohols added to the one hand to achieve the stabilization of the release substances in the release agent dispersion and on the other hand the sliding properties to improve the release agent.

Also the addition of other auxiliaries and technological changes in the production of part release agents did not lead to any satisfactory results overall.

In the case of the use of solid or pasty release agents or unstable release agent dispersions is the implementation of an automated production process not possible for die casting of light metals and their alloys

The instability of such release agent dispersions leads to high working temperatures and complicated ones Casting molds to uneven coverage of the mold surfaces and thus to difficulties in removal ( At the same time, due to the content of non-volatile Substances from the decomposition products of various carrier media and additives on the mold surfaces are undesirable Residues that lead to technological difficulties in the die-casting process and considerable expense the maintenance of the molds.

Ultimately, the surfaces of the die-cast parts are given a non-uniform appearance and the residue is eliminated requires an intensive washing process of the cast parts »

Mold release agents containing oil and wax also have the disadvantage that considerable problems with regard to health, Work and fire protection occur.

d) Object of the invention

The aim of the invention is to overcome the deficiencies inherent in the known prior art, in particular the from the inadequate release agent combinations resulting technological problems in the implementation of the Die-casting process to be eliminated or eliminated as far as possible and the prerequisites for automating the die-casting process for light metals and their alloys to accomplish·

e) Statement of the essence of the invention The invention is based on the object of creating homogeneous, firmly adhering and low-residue release agent layers on the working surfaces of the die casting molds, which meet the requirements of the die casting process for light metals and their alloys according to the above objective.

The object is achieved according to the invention in that a mold release agent is applied to the working surfaces of the die casting molds is applied, which from a combination of aqueous solutions or · dispersions of at least one Carboxylate of metals in main group I of the periodic table of the elements and at least one carboxylate of metals of main group II of the periodic table of the elements or · of zinc and a system of di- and trihydric alcohols.

It has also proven to be useful if the carboxylates from the salts of metals of the I and II main groups of the Periodic Table of the Elements or of Zinc with aliphatic carboxylic acids with more than 10 carbon atoms exist·

It has also proven to be beneficial if the system of di- or trihydric alcohols from glycerine and a Diol consists, with the ethylene glycols being particularly have turned out to be advantageous

In the method according to the invention, the mold release agent is Can be mixed with water in any ratio and * is preferably sprayed onto the work surface applied to the die casting molds, whereby the water evaporation creates a homogeneous, firmly adhering and low residue · Release agent layer is generated

f) embodiment

KLe invention is to be explained in more detail below using some exemplary embodiments:

example 1

A die-casting mold is used for the die-casting of pure aluminum made of steel sprayed with a release agent of the following composition:

Potassium palmitate solution 10 SSig 15 parts Lithium stearate dispersion 40 5Slg 50 " Glycerine 10 "

Monoethylene glycol 15 "

Dilution with water 1:10

A homogeneous, firmly adhering and clear release agent layer is formed, which enables the die-cast parts to be removed from the mold well enables *

The residues on the die are small and easy to remove. The die-cast parts have a good surface quality on·

Example 2
For the die-casting of an aluminum alloy GD AlSi9Cu1, a die-casting mold made of steel is sprayed with the following combination of separating agents:

Uodium oleate solution 10 % Xg 15 parts calcium stearate dispersion 30% 5o "Magnesium oleate dispersion 3o $ ig 5 ⁿ glycerine 1ο"

Polyethylene glycol MG 200 15 " Dilution with water 1:15

ν rf Η *

A clear, uniform and well-adhering release agent film is formed, which enables very good demolding of the Die-cast parts made possible

The residues on the die-casting mold are low, the surface quality of the die-cast parts is very good

Example 3

I ^{1 For} the die casting of an aluminum alloy GD AlSiIOMg, the following combination of separating agents is used for spraying the die casting mold:

Potassium oleate solution 10% 15 parts Calcium stearate dispersion 50% 50 "Glycerin 3"

Triglycol 5 "

Dilution with water 1:20

A clear, well-adhering and homogeneous layer of release agent forms, which is excellent for demoulding Die-cast parts are also guaranteed in continuous operation, 20

The formation of residues on the mold is minimal, the die-cast parts have a very good quality surface

Example 4

I ^{1 For} the die-casting of pure zinc, a die-casting mold is sprayed with a release agent of the following composition: Uatrium stearate solution 10% 60 parts zinc myristate dispersion 40 $ Lg 20 "Glycerin 5"

Butyl glycol 10 »

Dilute with water 1:30

The uniform, clear and firmly adhering Trennmittelf To ensure a good release of the die-cast ·

With small and easily removable residues, the cast parts show a good surface quality

Claims (1)

Patent claims: 1 die casting process for light metals and their alloys, in which a mold release agent is applied to the working surfaces of the die casting molds, which Contains metal salts of aliphatic carboxylic acids and polyhydric alcohols, characterized in that as a mold release agent, a combination of the aqueous solutions or dispersions of at least one carboxylate of metals of main group I of the periodic table of the elements and at least one carboxylate of metals of the II. main group of the periodic table of the elements or of zinc and a system of two and trihydric alcohols are used, 2 · Pressure test process for light metals and their alloys according to claim 1, characterized in that the carboxylates from the salts of metals of the I · and II · main group of the periodic table of the elements baw · of zinc with aliphatic carboxylic acids with more than There are 10 carbon atoms. 3 · Die-casting process for light metals and their alloys according to claim 1, characterized in that the system of di- and trihydric alcohols from glycerine and a diol, preferably an ethylene glycol, consists· 4 · Die casting process for light metals and their alloys according to claims 1 to 3, characterized in that that the mold release agent is miscible with water in any ratio and preferably by spraying is applied to the mold surfaces »