US317533A - Ebic moetimee atkinson - Google Patents

Description

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v M @i ha nu Patented May 12, 1885.

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ATENT OFFICE.

MARTIN r. HAYFsoF CHICAGO, nlLIsoIs-,AssIGNoB o'F oNE-HALFTOFBED- y ERIC MOBTIMER ATKINsoIv, oF SAME PLACE P'Ro'csss oF CASTING METALS.

I SPBCPICATION forming part of Letter! Patent N0. 317.533, dated Hay 1.2-, 1885.

Application lll-ed Novembertl, 1884.- (No specimens.) l 1/ To all whom it may concern:

Be it known that I, MARTIN P. HAYIB,.a

citizen of Great Britain, residing at Chicago,

in the county of Cook and State of Illinois, have invented certain new and useful Imrovements in Processes of Casting Metals, o which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to a method of casting metal articles; and the novelty consists in the man ner of carrying out the same, as will be fully hereinafter described, and specifically?v a condition that no change takes place in the pointed out in the claims.

- In casting asheretofore practiced it has been a desideratum to obtain a metal as free as possible from crystallization and blow-holes. These features are caused by the motion of heat from the molten body of metal in the direction of the nearest cooler surfaces, affecting the atoms of 4 metal to vibratory motion, and the presence of air in the molds causes an evolution of gases, which causes blow-holes in the casting. When the metal becomes cooled, this crystallization causes weak brittle castings. It is my design to prevent this crystallization, and to this end I propose to cool very slowly to prevent the travel of heat from vibrating or giving motion to the atoms of metal until it reaches a plastic consistence, in which state the atoms are not so liable to motion from this cause, and in which crystallization is not liable to occur to the same extent as in ordinary casting. .With this same object in view various attempts have been made to produce superior castings, and molds have been made of such refractory material that they have been susceptible of being raised to ahigh temperature. In the attempt to produce a better quality -of metal the same has been cast in vacuo, xthe molds being made air-tight and the air ex- ,hausted at some period during the process of xiillin Wigth these worthy attempts in view the objectof my invention may be said to be to pregvent crystallization and to produce a more lperfect casting at a minimum cost Iprevent crystallization byraising the temperature ef the metal when it is poured Into the molds to, say, 2,300 Fahrenheit. This temperature I retain through the mold for a considerable time after the metal is poured in, and this prevents any considerable current of at a high temperature in the molds for some time after it is' poured in, I prevent the evolution of gases and the formation of crystals,

thus producing what is called in the trade a solid casting. I, in other words, attain such state of the metal when it is placed in the molds, and then so retard the cooling that the metal has assumed a pasty, condition before a suicient force has developed by radiation of .heat to cause crystallization. In order to attain this condition, I employ molds made entirely of refractory material--such'as tire-clay or mixture of lire-clay and plumbago-and I polish the insides of the molds with a thin coating of plumbago and sour beer. .These molds are made sufficiently stout to resist the pressure of the metal by their own strength and withoutthe aid of other metal or casings or asks,which would interfere with the application of great heat to theexterior surfaces. T he molds are formed, dried, and baked in two or more parts, and these partsv are brought together and cemented properly to each other to make air-tight joints. This joint may be made with a luting of silicate of soda, fire-clay,

fine linseed-meal, and water or sour beer. Each mold complete is made with two pipeconnections, one to be connected with an airpump and the other with a pipe for admitting the molten metal.

In casting tires or blooms for making locomotive-tires, for instance, I provide a series or stack of furnaces. As an example ofthe means for carrying my process into practical use, I append hereto a set of illustrationen' n which- Figurelshows an exterior view of a furnace and a set of molds therein having their connections made with an exhausting apparatus and source of metal supply. Fig. 2 is au internal sectional view of such furnace,showing tuyeres for an injection of a blast to produce an intense heat. Fig. 3 represents sectional views of a tire-mold.

In the drawings, in which like Iettersof reference denote like parts, M designates the mold; A, thefurnace; D, the doors thereof, and Q the tuyeres for the injection of a blast to produce intense heat to the interior; B, thesmokestack; E, the exhaust-connection, and P the connection with a source of moten metal, these latter pipes, E and P, being provided with proper cocks and valves e p, respectively.

The furnaces, but one of which is shown, being preparedand charged with a proper layer of coke, and the molds prepared and placed in position,and the air-pipes and metalsupply pipes connected, and the joints in the molds luted, the fires are started. When the molds have reached a white heat, the-air is withdrawn from the interior of the molds,and the stop-cocks ein the air-pipes E are then closed, care having been taken to have the molds reach a heat corresponding to that of thc molten metal, and the metal admitted to the mold in suiiicient quantity through the pipes l?, the valve of which is then closed to cnt oil' the supply of metal. By means of the tuyercs the heat can be properly adjusted to allow the molds to cool very slowly-'say ten to iiftecn days; but I would have it understood that the time for cooling willvary with the weight and shape of the castings. The molds are then removed and separated carefully to allow their` reuse.

This invention must not be confounded with simple casting in vacuo, nor simple slow cooling. It consists in a succession of steps and conditions, which combined go to makeanovel and successful method for the purpose described.

What I claim as new isl. The process herein described of casting metal, which consists in first subjecting in a furnace air-tight molds made entirely of refractory material to a heat approximating that of the molten metal to be cast, then exhausting the air and introducing the' molten metal,

and nally slowly reducing the temperature.

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