US2841846A - Method of making metal castings - Google Patents

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vJuly 8, 1958 KoKicHl oTANl METHOD OF MAKING METAL CASTINGS Filed Jan. 8, 1954 KoKlCH/ @TAP/l Y ZLLMS Patented July 8, 1958 the.

METHOD F MAKING METAL CASTINGS Kokichi Otani, Minato-ku, Tokyo, Japan Application `lanuary 8, 1954, Serial No. 402,895

Claims priority, application .lapanfMay 19, 1953 Claims. (Cl. 22-201) This invention relates to a method of making metal castings, characterised in that the rst molten metal is poured in upwardly from the lower neck sand mould of `a mould which is provided with sand moulds arranged connectively to the top `and bottom of a body portion mould and after the pouring has been finished, the metal is allowed to stand for a suitable length of time, and after the rst metal has solidified in the body portion mould, a drainage outlet is pierced to drain out the iirst molten metal deposited in the lower neck sand mould 'while a second molten metal is being poured downwardly from the top of the upper neck sand mould so that the latter metal replaces the rst.

In conventional methods of casting where the inner metal is replaced, the first metal is led into the mould by means of a runner and when this solidies in the body portion mould, the iirst molten metal is drained out through the runner while pouring in the second metal, thereby replacing the first metal with the second. Accordingto these methods, the runner is restricted for the reason that the rst molten metal passes through the same when it is being drained out. Consequently, when the runner solidilies during casting, it is no longer possible to perform the function of replacing the metals. Therefore, regardless of how skilfully this is done, there is a limit in time for which the rst metal can be allowed to stand, which is 2-7 minutes. In view thereof, the outer layer (first metal) becomes thin and it is impossible to make it thick, and further since the second metal erodes the rst,

the object of replacing cannot be realized. Conventional methods in casting chilled rolls have, therefore, been only applicable to large rolls for sheets, and they cannotbe applied to small rolls for sheets or rolls for shapes.

However, according to this invention, the metal deposited in the lower neck sand mould is drained and replacement is carried out without using'the runner, and so there is no dilculty resulting from the first metal solidifying. It is, therefore, possible to extend the time for which the iirst metal is allowed to stand and obtain a casting with a thick outer layer. Also, according to the heretofore known methods, casting was possible only up to the second metal, but with the method of this invention third, fourth and further replacements can be carried out and since the chilled layer can be made thick, it is possible, without making special caliber roll casting moulds, to easily make cali-ber rolls by cutting Vdesired grooves in the castings. Further, in case of casting by means of special caliber roll casting rolls, the chilled layer'at the vbottom of grooves is so eectively thickened Vas such that could not be achieved by the heretofore known c'astingmethods.

The drawings illustrate an example of an apparatus which may be employed to practice the kcasting method of this invention. In the drawings, Fig. 1 is a vertical crosssectional view of the said apparatus for carrying out this invention in casting chilled rolls; Fig. 2 is a cross-sectional view taken on line A-A of Fig. 1; and Fig. 3 is a vertical cross-sectional view of the said apparatus employed in casting steel ingots. The same numerals in the drawings denote the same or equivalent parts.

In explaining an example of this method carried out in casting chilled rolls as shown in Figs. 1 and 2, sand moulds b, c are arranged connectively to the .top and bottom of body portion metal mould and further a storage chamber (sand mould) d which is constructed for keeping warmth effectively is provided at the bottom of lower neck sand mould c. On the other hand, a pouring gate 1 is opened at the side of lower neck sand mould c to which is arranged connectively a pouring canal (runner) 2, and outlets 3, 3, 3 are provided in the bottom storage chamber d (diameter of the opening being 5 mm.- 25 mm.) and plugged with clay, coke or the like.

Chilled cast irone is thus poured into moulds c and b through the runner 2 and pouring gate l and after having finished pouring in this metal, it is allowed to stand for a suitable, desired length of time. When a chilled outer layer has formed in the body portion, one of the outlets 3, 3, 3 of the bottom storage chamber d isl pierced with a sharp-pointed bar to drain out the molten metal mass while pouring in a second metal from the top. The said outlet (since the diameter of its opening is small, when a cold metal is applied thereto, that part of the molten metal will solidify and stop the drainage) is suitably stopped after the second metal has replaced the first. When it is desired to continue replacement of metals again, a new `outlet 3 -is pierced with the bar to drain out the molten metal; According to .this method, even if the length of time heretofore allowed to stand of 2-7 minutes is extended to 15-30 minutes, replacement can be carried out and it is possible to make the thickness of the first metal as one desires and to an adequate extent.

:It is also possible to easily make rolls of small diameter which solidify quickly, for example, rolls small in diameter such .as diameter of body.300 mm. x length of body 1000 mm. which were considered impossible up to now. Furthermore, the heretofore known methods of casting where replacement of metals are done were only capable to the extent of the second metal, but according to the present invention, third, fourth, fth and further replacement castings can be carried out to produce composite rolls. Since the chilled .layer can be made thick, it iseasy to make, without using any special mould, caliber rolls by making plain rolls and cutting ,desired grooves therein.

An example `showing the cast iron poured in this case is as follows:

Si Mn First metal Second metal... Third metaL- @man bottom-of the body portion metal mould a, and a storage chamber (sand mould) d which is constructed for keeping warmth effectively is further arranged connectively at thevbottom Yof lower neck sand mould c.

On the other hand, a pouring gate 1 is opened at the side of the lower neck sand mould to which is arranged connectively a .pouring canal (runner) 2 and. also at the bottom storage chamber d are provided outlets 3, 3, 3 (diameter of opening being 5 mm.-25 mm.) which are plugged with clay. The molten `metal is thus successively poured upwardly into moulds cfa'andfbrthrough the'pouring canal 2 and pouring gate 1 and after the pouring has been finished, the metal is allowed to stand for a suitable, desired length of time; and when it has lsuitably solidified in the body portion metal mould a, one of the outlets 3, 3, 3 of the bottom storage chamber d is pierced to drain out the bottom molten mass while a second molten metal is .being poured in from the top of the upper neck sand mould b so that the second molten metal takes the place of the first, at which time the said opening isv suitably lstopped (in view of the small diameter of the opening, when a cold metal is applied thereto, that draining any further).

In case it is desired to continue replacement of metals again, a new outlet 3 is pierced to drain out the molten o si Mn P vs V or N1 First metal 0.10 0.075 0. 45 0.05 0.05 second metal 0. 45 0.35 0.00 0.05 0.05 0.50 1. 50

The balance is iron. Y What I claim is:

1. A method of making metal castings comprising the steps of introducing a first metal batch in a mold through an inlet opening spaced from the top and the bottom surface of the mold so that the metal ows first downwardly to form a reservoir of hot metal below the inlet'opening and then rises upwardly in the mold; chilling a portion of the mold spaced from and above theinlet opening to solidify a portion of the metal extending from the chilled part of the mold to a desired thickness; draining the nonsolidied metal in the mold from the reservoir of hot metal formed below the inlet opening and simultaneously pour-V ing a second batch of metal from the top of the mold to displace the non-solidified part of the first metal batch; stopping the drainage after the displacement has taken place; and letting the second -batch of metal also solidify in the mold. v l

2; A method of making metal castings comprising the steps of introducing a first metal batch in a mold through an inlet opening spaced from the top and the bottom surface of the mold so that the metal iiows first downwardly to form a reservoir of hot metal below vthe inlet opening and then rises upwardly in the mold; chilling a portion of the mold spaced yfrom and above the inlet opening to solidify a portion Vof the metal extending from the chilled -part of the mold to a desired thickness; draining the nonsolidied metal in the mold from the reservoir of hot metal v formed below the inlet opening and simultaneously pour- .part of the molten metal will solidify land stop it from ly to form a reservoir of hot metal below the inlet opening and then rises upwardly in the mold; chilling a portion of the mold spaced from and above the inlet opening to solidify a portion of the metal extending from the chilled part of the mold to a desired thickness; draining the non-solidified metal in the mold from the reservoir of hot metal formed below the inlet opening and simultaneously pouring a second batch of metal from the top of the mold to displace the non-solidifedfpart of the first metal batch; lettinga portion of the second metal batch eX- tending from the solidified portion of the first metal batch solidify to desired thickness; draining the non-solidified metal in the mold from the reservoir of hot metal formed below the inlet opening and simultaneously pouring a third batch of metal from the top of the mold to displace the non-solidified part of the second metal batch; repeating the last-mentioned twoV 1operations until a desired plurality of metal layers are formed; stopping the drainage after each displacement has taken place; vand letting the last batch of metal also solidify in the mold. Y

4, A method of making metal castings comprising the steps of introducing a trst metal batch of high alloy steel havingin the solidified state a great hardness and great 'wear-resistance in a mold through an inlet opening spaced from the top and the bottom surface of the mold so that the metal flows rstdownwardly to form a reservoir of hot metal below the inlet opening and then rises upward- .ly in the mold; chilling a portion of the mold spaced from and above the inlet opening to solidify Aa portion of the ymetal extending from the chilled part ofthe mold to a desired thickness; draining the non-solidified metal in the mold from the reservoir of hot metal formed below the ,inlet opening and simultaneously pouring a second batch of metal of'a low'alloy steel having in the solidified state a hardness lower than said first metal batch and good machining qualities from the top of the mold to displace the non-solidified part of the first metal batch; stopping the drainage after the displacement has Vtaken place; and

letting thesecond batch of metal also solidify in the mold.

5. A method of casting a roll with its yaxis in vertical position having a central portion with a large diameter and bearing portions located adjacent-opposite ends of the central portion and having a diameter smaller thanV the diameter of the central portion `comprising thesteps of introducing a first metal batch in the mold through an inlet opening communicating with the part of the mold forming the lower bearing portion so that the metal ows first downwardly tovform a reservoir of hot metal below the inlet opening and Vthen rises upwardly in the mold; chilling ing a second batch of metal from the top of the mold l 3. A method of making metal castings comprising the steps of introducing a first metal batch in amold through an inlet opening' spaced from the top and the bottom surface of the mold so that the metal flows first downwarda portion of the mold which forms the central portion of Y the roll t-o solidify a portion of the metal radially extending from the chilled partV of the mold to a'desired thickness;

draining the non-solidified metal in the mold .from the reservoir` of hot' metal formed below the inlet opening and simultaneously pouring a second batch of metal from the top of the mold to displace the non-solidified part of the first metal batch; stopping the Vdrainage after the displacement Yhas taken place; and letting the second batch of metal also solidify in the mold.

Great Britain Jan.V 26, 1,928

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