DE1558112A1 - Lining for casting or similar forms for casting ferrous metals or their alloys - Google Patents

Description

DIETRICH LEWINSKY

PATENT ADVOCATE 8 Munich 42 - Gbtthardstr. 81

Telephone 56 17 02

f 7.> *;

Henri Jean Daussan, 9 »Avenue Leolere de Hauteeloque, Metz (France)

"Lining for casting or similar forms for casting ferrous metals or their alloys"

French priority from the French patent application of June 30, 1966 PV 0576 (Metz)

The present invention relates to an improved liner for the continuous or discontinuous casting of ferrous metals or their alloys in casting or similar forms, especially in those for preforming ₀ The invention has especially the object, the means for improving the quality of Gußstüoke or mold parts for yield _β

It is known to delay the solidification of the upper part of the casting in order to reduce the amount of shrinkage caused by the discontinuous casting of steels

009812/0651 B ^ O ORIGINAL - 2 -

To fill voids «,

In the French patent 864 420, for example, an OuSsapfen of a mold is described "whose composition is characterized by the following three classes of substances - a granular refractory material" an organic material in fiber form and a binding agent.

Presently known numerous preparations for lining molds or insulating panels, which are based on ternary mixtures of this type »This lining preparations" in which the Venrendung is excluded from such materials "the sohmelsen at the temperatures of" all have a common seed shortage " namely a bu high content of organic matter "of the primary application of the present invention serious consequences · Indeed, these organic materials can not maintain the high temperatures" which prevail at the Grenzechioht metal lining "if the cast metal old liner comes into contact. Special leg "allguB" , whose acidity is, for example, "about θ minutes" already leads to the heat " emanating from the pouring stream" to the destruction of the organic material of the lining. It even happens that "this splits" after it has been exposed to the thermal radiation of the casting stream . The liquid metal "that in

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If it comes into contact with the lining, it can then adhere to the organic particles, which are thereby destroyed. When the cast metal has solidified, does one find that the lining, or at least a layer of that lining? is as held by a plurality of small rivets firmly to the surface of the casting adheres · By this adhesion, the operations _f where the casting is later subjected, geatürt. These disturbances are accompanied by the destruction of equipment as well as metal losses through AusohuSo

According to the invention , the above-mentioned disadvantages are now avoided by using outer clothing with which remarkably good metallurgical results are obtained, as there is no longer any sticking to the casting during its removal from the mold and handling and setting up are extremely facilitated thanks to very , great ease and a sufficient strength of the eo manufactured objects

According to the invention , the lining for casting or similar forms " which contains a refractory, granular layer, a fibrous layer and a binding agent, among other things, is characterized in that it - in percent by weight soaked on ! Dry substance" = "the following composition

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owns: 5-25 $ of a porous-granular Sohioht of refractory Material, 25-80 # of a non-porous-granular layer of refractory material, 5-25 # of a fibrous layer of refractory material, 2-25 # of a binder and 0-40% of a exothermic layer, the content of organic material must not exceed $ 12 o

By "refractory ¹ * are p of Torliegenden description and the following claims, to be understood substances that τοπ at least up to a temperature of 800 ⁰ C is not sohmelzen · piping term includes so AUOH substances" which in general will be called 'semi-fireproof ^H .

A refractory material with porous grains means refractory materials with natural cavities eu, whose cavities are in communication with one another or not.

Tests have shown that liners of the invention only light weight combine with sufficient strength, but without the above mentioned laohteile to have the molten casting terms ₀

Only the practical types of application according to the invention are to be explained in detail _o

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BAD ORiGiMAL

Numerous experiments have shown "that the inventors" " appropriate finishing preparations are particularly advantageous if they correspond to the following composition!

Refractory material with porous grains Stretched perlite, spherical alumina, fossil silica, metallurgical coke or similar materials ........ ·. · ... · ... 5- 253 *,

Kieselguhr, magnesia, chamotte, rertohledtne Slag, raw or burnt dolomite or

similar materials »50 - 80 *,

Refractory material in Taeernt Asbestos, certain glass fibers or others Mineral fibers * ··. ·. · 5 -

Organic and / or mineral-based binders, which can be of synthetic and / or alneralieohen origin :

Pormaldehyde-phenolic resins, starch- or guemi-containing binders, formaldehyde-urea haree, puranharee, terpene resins, polyvinyl acetate, epoxy resins or even sodium or potassium silicate, aluminum phosphate, clay, concrete. ... ο ........... ₉ 2 -

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So has ζ.B, a lining according to the invention, which like The following was composed “brought very good results

Phenolic resin pulTer Silica sand

Asbestos ο

elongated perlite. . . . li »

Thus, a lining of this composition for lining a mold for castings of 5-6 tons in weight a bead of about 25mm and a diohte, based on Water, from 0.85ο their total weight is 25kg, and theirs Strength is sufficient to allow them to fall to the ground from a height of about one meter without breaking to fear »

On the other hand, it has been found that when the content of organic materials is higher than 1256, these materials are not sufficiently refractory, then ice is not sufficient from the heat from the refractory materials with which ice has been mixed, so a content of # 12 seems to be the upper limit that does not may be exceeded.

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With regard to the grain size of the refractory materials used for the linings according to the invention, it is recommended that a single grain size of 3mm should not be allowed for grains of either type. Ubersohreiten. Preferably, the grain size should be up to one millimeter · · Particularly suitable particle sizes are the following when the porous granules a diameter up to 1mm su, on niohtporöeen grains of a soloher O ₁ OS 0.25mm.

BeBUgIioh of the fibrous, refractory material is According to the invention it is provided that its length is not 25m Exceeds, while its diameter is up to su 1b «, ▼ orsugswelde, the mean length of the fibers is 5-13 · «· Dl · experience has increased that fibers with a length from 8-1Grandma and 'a Durohmeseer up to 0.2mm especially are well suited »

Furthermore, according to the invention up to below 25J * binders are used used, on condition that the ffesamtantell at The organic material in the lining does not exceed 12%, so that the organic content cannot exceed 12 *

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Haoh one embodiment of the invention includes the Lining up to bu 2Jl organic weeders, * .B. tob jute » Sawdust, paper pulp, etc. The proportion is preferably on organic fibers not more than 1.5 ^ # special then »if a binder of organic nature is used in this In this case, the following procedure will be used: organic binder and organic fibers stay below 12 #, but you can also add a mineral binder » to improve the strength su.

Contains another embodiment of the invention the lining is an exothermic material · In this «VsU the proportion of refractory material with non-porous Grains are reduced in size, so that it is only 25-40j ( of the preparation is · The exothermic material is like known to be advantageous from substances together, whose caloric effectiveness on the ohemisous beactlon «wieohen based on an oxidizing agent and a reducing agent " These substances are intimately mixed with one another under Susatc a fluid and one of the above refractories Materials · The following are particularly advantageous Substances used

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«9

Reducing agents (single or mixed): Al, Si> .FeSiMgj ffeSiAl, SiOa, 0;

Alkali nitrate, manganese dioxide, iron oxides, magnesia; elg, cryolite, P3.uss-late. '

The actual exothermic mixture (reducing agent + Oxidizer + Flux) makes 10-50 $ the weight of the refractory material? wherein the proportion of the oxidizing agent about 15 - 5Qi of the reducing agent and the proportion of the flux also 15 - 50 & of the reducing agent, «. ,, If, for example, the following exotherm is preferred Mixture used:

Aluminum * "... · · 100g

Sodium nitrate » . . . 15-5Og river-late., *. ·. ···. · '■. 15-5ög.

According to a particular embodiment, the lining according to the invention has open sides on the inside

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exothermic platelets of the casting mold »which are attached to the side» that comes into contact with the metal to be cast. These papers advantageously have the stated composition, i.e. a mixture of fire-resistant material, Reducing agent »PIuB- and binding agent. You get eo

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a liner, which has an insulating layer on the side which is in contact with the mold, and an exothermic layer on the side has, which is in contact with the metal "Such a composite liner can becoming prepared by two different methods

a ) separate production of both the insulating and the exothermic lining and attachment of the exothermic to the insulating lining outside the mold. The type of fastening can be any conceivable, namely gluing using one of the above-mentioned binders or fastening using various mechanical means, such as metal hooks, or also, in the Pail of an insulating lining made of one piece, pressure-free pressing ZoB. in a press of the preformed exothermic lining to the inside of the insulating lining «

b ) The composite lining is produced at once by introducing the insulating and exothermic materials into the torrn in a certain order »

Sin advantageous process for the production of the linings according to the invention, after which you get very good results Achieved, consists in that one is an aqueous phase

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served. For this purpose, the various ingredients are mixed to form a flowable aqueous paste. In this way, the solid materials are brought into the mold, the insides of which are permeable to water. This filtration can take place on its own or it can be artificially accelerated. After removing the excess water, the cake obtained can also be pressed and then dried, either in a drying cabinet or in the open air, whereby the type of binding agent determines the drying temperature *. Thus, a synthetic binder such as a thermisoh curable resin is a temperature of about 150 ⁰ C in the present invention perfectly adequate in the case of "

However, a lining according to the invention can also be produced in a dry or only slightly moist way without using a purely aqueous phase. The procedure then depends on the type of binder used. If the binder is, for example, a synthetic, thermosetting resin, you press and raise the temperature simultaneously or successively. If the binder is suitable, it can also be hardened by the action of CO ₂ . This is the case when the binder is a sodium silicate with a known ratio of silicon to sodium and a known dry matter content ίβΐτ «

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Claims (1)

Expectations" 1, the liner for casting or similar forms, consisting u "a" made of a refractory granular material "a fibrous material and a binder, characterized in that said liner - percentage by weight based on dry substance - having the following composition: 5-25 $ a porous-granular refractory material, 25-30 $ of a non-porous-granular refractory material, 5-25 $ of a fibrous refractory material, 2 ~ 25 # of a binder and 0-40 £ of an exothermic material, and because the content of organic material is at most 12 # _o 2. Lining according to claim 1 »characterized in that the porous-granular refractory material contains at least one of the following substances: elongated perlite, spherical Alumina, fossil silica, metallurgical coke 0098 1 2/0651 - 2 3. Lining according to claim 1 »characterized in that the non-porous-grain refractory material contains at least one of the following substances: diatomite, chamotte, magnesia, Slag, raw or burnt dolomite Ao lining according to claim 1, characterized in that the fibrous refractory material contains at least one of the following substances: asbestos fibers, glass fibers o 5β lining according to claim 1, characterized in that the binding agent is a mineral product such as sodium silicate, potassium silicate, aluminum phosphate, clay, betonite, etc. 6 ο Lining according to claim 1, characterized in that the binding agent is an organic product such as "B" formaldehyde-phenolic resin, a starch * or rubber-containing binding agent, urea-formaldehyde resin "Furanhara", terpene resin, polyvinyl acetate, epoxy resin and the like. 7 ο lining according to claim 1, characterized in that the refractory grains have a diameter of up to 3mm « 8ο Lining according to claim 7, characterized in that the porous refractory grains have a diameter of up to one millimeter 0098 127 0651 f ¥ 9ο lining according to claim 7 »characterized in that the non-porous refractory grains have a diameter of 0.05-0.25mm. 10o lining according to claim 1, characterized in that the refractory fibers have a length of at most 25mm and have a diameter of 1mm or less. 11. Lining naoh claim 10, characterized in that the refractory fibers have a minimum diameter of 0.2mm and have a length of 8-10mm 12ο lining according to claim 1, characterized in that the proportion of organic fibrous material is O-2? 6 13 * lining according to claim 1, characterized in that it contains an exothermic material in an amount of 10-5O ^ of the refractory material and 25-4Ο56 of the total Lining, this exothermic material consisting of an oxidizing agent, a reducing agent and a Flux composed 1st 14o lining according to claims 1 and 13 »characterized that it contains an exothermic layer on the side that comes into contact with the metal to be cast, during the Part that is in contact with the mold, no part exothermic material contains nr) Qß12 / 0651