US1458222A - Method of gating castings - Google Patents

Description

J. F. ,DIETER VMETHOD OF' CTATING CASTNGS .Fume H2, H923.

Filed July 18, 1921 mmf@ NM x

SWW/Wto?, lm z;

Patented dune l2, i923,

Moron4 Germany, or NEW Yoan, n.

Application filed July 18,

To all tti/0m it may concern.'

Be it known that I, JAMEs F. DIETER, a citizen of the United States,y residing'at lflighland'?ark, in the State offNew Jersey, 5 have invented certain new and useful lmprovements in Method of @rating Castings, of" which the following is a specilication, reference bein had to the accompanying drawing, forming a part hereof.

This invention relates to an improved method of gating castings of metal of low speciiic heat and particularly aluminum, and for convenience in the specification and claim wherein reference will be made to aluminum, it will be understood that any other metal which presents similar problems in casting is contemplated as an equivalent.

The properties of aluminum are such that it cannot be cast readily because of the rapid rate of cooling. In different parts of such castings it has heretofore been very diliicult to secure a uniform rate of cooling with the result that one part has often cooled more readily than another and resulting stresses produce cracks or porosity. To meet this condition makeshifts have been employed in the form of chills embedded or rammed in the cores or molds and these chills have usually been placed in the core boX at points where it was desirable to accelerate the cooling to keep pace with cooling at other points. For instance, it has been the practise to place chills where the bulk of metal is greatest. The initial expense of making these chills, the labor of installing them and the cost of replacement has made their use very undesirable and it is believed that unfavorable conditions in the casting itself are apt to be created by the presence of chills.

ln the usual method of gating, risers are placed near they heaviest metal parts and communicate with the mold. These risers serve the purpose of supplying a head or pressure to the metal in the mold and also a reserve to lill up the space left by contraction in cooling. Since the metal entering the risers flows from the mold and is the first metal poured, relatively speaking, it is natural that it should become somewhat chilled before reaching the risers and have a tendency to freeze therein. rl'his condition, particularly in the casting of aluminum, defeats one of the principal purposes of the e @eresmas METHOD or serine cnsrrrves.

metal in the risers since it doesnot constitute a hot and effective' reserve.

ln accordance with the improved method chills are' veliminatedl and yet such condi-l tions are setup as will insure a uniform coolingthroughout the mold', all parts ot the casting been maintainedV at a sutlic-ient high temperature, during the cooling, by the hot metal within the risers. To accomplish this the risers are gated in the runners. The metal is fed in uniformly through the pour- .ing basin and passes through the runners to the mold. The risers are gated in the runners so that the metal ultimately held in reserve therein is the last metal poured and hence the hottest. This hot metal effectively in maintaining the temperature throughout the casting so that it will be caused to cool uniformly. There is illustrated in the accompanying drawing in somewhat diagrammatic form a. gate embodying the invention.

ln the drawing- Figure l is a view in plan of a ask showing the risers into the runners.

Figure 2 is a view in vertical section through the flask shown in Figure 1 and taken along the planes indicated by the broken lines 2 2 of Figure l and looking in the direction of the arrows.

As the description proceeds it will be evident that not only is the invention not limited tothe character of the metal employed in casting but, further, is not limited to the type of casting or flask. Variations in the form and disposition of the pouring basins, runners and risers will suggest themselves to one skilled in the foundry art and be adapted to prevailing conditions.

The flask a is shown as including a mold for any suitable casting. The pouring basins I), two in number, have communicating therewith the runners c through which the metal flows to the mold and in these runners are gated risers l in such number and posil large extent, the very purpose of the risers since' the metal therein has not been in a condition to supplya head or pressure and '.ill up the space left by contraction in cooling. Of course With metals,lik e aluminum,

of 10W specic heat the eect has been aci centuated to a, point Where freezing has `0ccurred.

In accordance with `the present invention the method ofgating is such that'contrary conditions vvare realized. The metal flowsl freely along the runners into the mold and f. sure uniform contraction While continuously Leccese 1N o chills are necessary and yet,.in practise,

better castings have `been secured than be# fore . I claim as my invention: l -K `The herein described method of casting comprising forming a riser in communication With the Arunner,V and between the pouring basin and' the mould properfwhereby the riser fills With .the last poured metaL, Which metal feeds into, and exerts pressure on` the metal in the mould duringthe cooling thereof. c This specification signed this ninth day of July, A. D. 1921.

JAMES E DIETER.l

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