US1699612A - belgium - Google Patents

Description

H. DOAT METHOD FOR THE PRODUCTION OF UNHRDENED QASTINGS IN METAL HOLDS Filed Oct. 26, 1925 Pateniea Jan'. 22, 1929.

* UNITED STATES rArENT) OFFICE.

HENRI* lio-AT, or BRUSSELS,` BELGIUM', ASSIGNOR To COMPAGNIE GENERALE DES 'coNDUIY'rEs DEAU, socIE'rE ANoNYME, oF LIEGE, BELGIUM.

- ME'rHoD FoE'rHE PnonuC'rIoN OEnNIiRDENED CASTINGS IN METAL Moms.

unhardenedcastingsin metal molds.

' .[lhis invention relates tothe productionofr castings, that l form on the surface .of the casting. In order to preventfthi's phenomenon it is usual to provide the mold with a'lining which prevents l the coolingfrom taking place so rapidly as to lead to the frmation of suchouter layer of white cast iron. v TheV present invention is specially dlrected to the production of unhardened castlngs by making ruse of a lining material which also .present-s additional advantages.

Said linin acts not only as a means of protection fort `e mold `itself and for preventing a too rapid cooling of the metal remaining 2o in contact therewith during the castlng rocess, butalso serves a physico-chemical unc;

tion Which-cooperates with those just menv f tioned' in causing the formation of a supericial layer of grey cast iron on the casting,

said, layer 'being characterizedby flakes of .graphite 'without any large excess of cemen' tite.

Accordin to the invention, said vlining is composed4 'ogf siliconor oan -alloy or substance containing; silicon in the free state, in combinationor in solution.V U According t .one method of carrying out the invention in a particularly advantageous manner from-the oint of view of the cost of ferro-silicon.

productiomfsaidlining may becomposed of fIn thelcase of ironcastings, the physicoplace result 1n chemical phenomena taking increasing the tendencyof t e iron carbide to decompose 3in such a Way-that, in spite of the high rate of cooling of the outer layer, the FesCv-.tli'erein .is reduced to -its elements and therefore furnishes a Vgrey cast iron characterized by-akes of graphite Without any large and, on the other hand, of considerably gal force.

excessief cementite, in place of a white cast he Working life of the metal Appucatioi; inea october 2e, 1925, seria/i ir. 34,879. and 11i-Belgium November 4, 1924.

ing, the invention provides for the distribu- ,'A'tion of the ferro-si1icon, orthe substance or It is known# connectionwith making ironv fiile sudden contact'of the mol J5 ten metal with the metal sides of themold` causes an outer layer of White cast iron toi alloy-mentioned above, over the interior surface of the mold by the action ofthe centriful With this object, these materials may be in' troduced into the mold, which rotates on ,an approximately horizont-al axis, said introduction being effected either -by means of a trough extending all along the mold 'or by means of acharging nozzle. In the latter case a relative longitudinal movement is im;` parted to the rotary mold and said nozzle. i In order 'to turn out the maximum numberl` of castings in a given time, andespeciall-y the 1,70' largest number of pipes in the case of a rotary cylindrical mold, the invention also provides for the introduction and centrifugal distribu tion of the said lining material Just prior to the introduction-of the molten metal.

In the case of molds having a large inner surface, these successive introductions may be effected .onportions of 4said surface and before the Wholeof the surface has been covered with the lining material.

The .invention also provides for the restriction of the application ofthe lining material to certain parts only ofthe mold, the other v parts being left bare or covered with a lining .of diiferentthickness from that on the lirst S5 parts aforesaid.

. case a mixture containing 40 to 80% of silicon may be used, though, o f course, in certain contingencies, the percentage of silicon may be outside these limits. In some cases, ferrosilicon may be replaced by a material containing a different product alloyed With silicon.v In some cases, use may also be made of pure 100 silicon, which acts simultaneouslyas a chemical agent yon the metal of the casting and as a protective agent onthe mold itself.

The substance or alloy with a silicon base may be used either lin the' form of a paste, 105 rendered adherent bymeans of a binding medium of any kind, or in the state of a more or less fine ypowder. -1 f The material employed may be placed in position prior to each casting process in order -to -repair the lining, a portion of which is an adhesive substance, sueltas gluten, linseed oil, molasses, rosin, varnish, fiour, dextrin or colophony; This coating may be applied, for example, by means of a brush, a vaporzer or an atomizer.

The mold may be heated to al certain temperature, or the material with asilicon base may be heated prior tits introduction into ,into the mold by hand, either while the mold is stationary or rotating, if themold is a short one. Y

In the case of a longer mohhfsuch as is used, for example, in casting pipes, use may be made, for example, of one or the other of the devices illustrated in the accompanying draw'- ings, wherein Figure 1 is a perspective view, in partial section, of a typical rot-ary mold provided with a single trough for the distribution of the lining material.

sary to arrange forthe-production of arela'- titve longitudinal movement, equivalent to the length of the mold, between the mold and the nozzle.`

In order to ensure the quick suc ession of the operations of distributing the ubstanoe with a silicon base andthe pouring of the molten metal, the invention provides for the arrangement, inthe interior ofthe mold' (see Fig. 2), of two guide rods 3, on which the trough 4 containing the silicious material and the trough 5 containing the molten metal are l adapted to slide 'and tilt in succession, inthe directions indicated bythe arrows.v v It will be understood that thetwo troughs may be interconnected and arranged in-such a manner as both to tilt in the same direction, for example aroundthe same axis, so that the successive distribution of the silicious material and the molten metal may be eeeted automatically by a single actuating means.

It should be noted that the invention also provides lfor coating portions only of the mold with the' silicious lining, leavingother portions bare or covering them with another kind of lining'. In using a trough for the distribution of the silicious material, this result could be accomplished, for example,

by providing the trough .with lateral compartments, some being charged with the ma-l terialfand others leftempty.- In the case of a noz'zle, a cock controlling the delivery couldv Figure 2 is a cross section'through a rotary* be provided.

mold provided with two troughs for the distribution of the lining material and molten metal respectively.

In the case of Figure l, aI trough 1 of approximately the same length as the mold 2,

is adapted to slide on a guide roet 3 and to pivot on same so as to discharge, into the mold, the substancegwith aislieon base with@ which said trough is charged; L

This substance is then distributed, bythe centrifugal force, all over the sides of "the mold, and when this has been done, the molten meta-l can be poured in.

It will be understood that the trough might" be replaced by a nozzle discharging the said substance. In such' caslgin order to cover the sides of the mold all over, t'will be neces- What I claim is: In a method of producing unhardened ca ings in rota-ting metal mo1ds,the step of-in- Y troducing into the mold, While it is rotating and prior to the introductionof the molten e metal, a ferro-silicon alloy` i the vstate -of loose powder, the grains thereof being heldv against the surface of the rotating mold.- by;

centrifugal force; said alloyforming `a lining I which protects the rotating mold vduring' the casting operation and afterwards becomes incorporated chemically. in the outer portion of the casting to convert the white cast metlil into gray east" metal characterized'by?flakesV of graphite without large excess, of cementite- In testimony whereof I' alix my signature.,

HENRI BOAT..

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