US2045576A

US2045576A - Method of and apparatus for treating metal castings

Info

Publication number: US2045576A
Application number: US714741A
Authority: US
Inventors: Robert W Bedilion
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-03-09
Filing date: 1934-03-09
Publication date: 1936-06-30
Anticipated expiration: 1953-06-30

Description

June 30, 1936. R, w BEDILION 2,045,576

METHOD OF AND APPARATUS FOR TREATING METAL CASTINGS Filed March 9, 1934 4 Sheets-Sheet 1 I INVENTOB floer/ Mfieazlzon ATTO NEY June 30, 1936. R w; BEDlLlON 2,045,576

METHOD OF AND APPARATUS FOR TREATING METAL CASTINGS Filed March 9, 1934 4 Sheets-Sheet 2 INVENTOR #55671 lffledLziOfl BY ATTORNEY June 30, 1936. R w BEDILION 2,045,576

METHOD OF AND APPARATUS FOR TREATING METAL CAS TINGS 4 Sheets-Sheet 5 Filed March 9, 1954 iazwr w gdiz June 30, 1936. R w BEDILIQN 2,045,576

METHOD OF AND APPARATUS FOR TREATING METAL CASTINGS Filed March 9, 1954 4 SheetST-Sheet 4 5 i IIIIIIIIIA 4 m I n .l u n v INVENTOR I ii oerf h/Z560L Zia/7 Patented June 30, 1936 UNITED STATES PATENT OFFICE METHOD OF AND APPARATUS FOR TREATING METAL CASTINGS 8 Claims.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) This invention relates to a method of and means for treating metal castings in the mold while the poured metal is still in the molten condition, to secure a, uniform time-rate of cooling of all parts of such casting, thereby eliminating draws and obviating the necessity of the use of chills.

It is the object of this invention to provide electrical means for applying heat to the less massive parts of a metal casting and progressively reducing the heat so applied to cause such less massive parts to cool simultaneously with the heavier portions.

It is a further object to provide means of the type mentioned to maintain the metal of a casting'in a liquid state for a sufiicient time to permit dross and gases to migrate into the riser and so be removed from the casting.

In the drawings:

Figs. 1 and 2 illustrate schematically one aption when, for any reason, it is undesirable to make holes through the flask walls;

Fig. 7 shows the positioning of the magnetic poles adjacent the thin parts of a casting in a 35 mold, together with thermo-electric elements embedded in the mold to indicate the temperature adjacent the thin parts of the casting;

Fig. 8 shows the poles provided with auxiliary pole pieces to heat the gate and riser of a casting. 40 Electric heating for furnaces, crucibles, and

even for molds in the form of crucibles, has heretofore been known, but so far as I am aware it is entirely novel to utilize induced electric currents in the lighter parts of a casting .in the ordinary sand mold to maintain the temperature of those lighter parts substantially equal to that of the more massive parts of the casting.

As shown in Fig. 1, I employ a ring 9, preferably constructed of laminae of soft iron having 50 apertures extending from the inner periphery to the outer periphery thereof through which the laminated poles I!) may be passed. The ring 9 may be either formed of annular laminae or it may be built up of laminated arcuate sections se- 55 cured together into a continuous body by mempoles Ill and are connected to indicating instrubers ll adjacent the poles I0. As is well shown in Fig. 3, the poles ID are held in position by plates l2 and I3 which are clamped against the lower and the upper surface thereof by straps l4 and bolts l5. If it is desired .to move the poles 5 into or out of ring 9, the nuts [6 on bolts l5 are released, the poles adjusted to the desired position and the nuts again screwed down, thus making any given ring applicable to various sizes of molds. While I have shown in Fig. la ring pro- 10 vided with four poles, it is to be understood that the number thereof may be either greater or less,

as occasion or convenience may dictate.

Fixed to ring 9 are a plurality of spools I! upon which are wound wire-coils l8 having a num- 15 her of turns suitable to produce the desired magnetic flux in the poles Ill. The coils I8 are so connected to the current supply that there are formed a, plurality of pairs of magnetic poles in each of which pairs the members are of opposite 20 magnetic polarity whereby a magnetic'fleld is set up between the members of each pair. It is readily apparent that when a fluctuating current is supplied to the coils I8 there will be a concommitant fluctuation of the magnetic field between the poles of each pair-and therefore currents will be induced in any electrically conducting material within such fleld and heat will be developed thereby.

The coils I8 are connected to terminal blocks I9 which are connected by wires 20 to.a load regulator 2| of any well known commercial type.

As illustrated, each load regulator 2| has a pilot motor 22 to change the magnetic linkages in the load regulator and thereby vary the output. The load regulators 2| are supplied, through bus bars 23, from a master load regulator 24 having a pilot motor 25, although in some cases the master regulator may preferably be omitted.

Each load regulator 2| is suitably connected, as by wires 26 having an inductive coupling with one of the wires 20, to an ammeter 21 on instrument panel 28 whereby the output of each load regulator may be determined for purposes of control. The pilot motors 22 and 25 are operated'by direct current from a supply line 29 and are controlled by reversing switches 30 and 3!), respectively, onthe instrument panel. The line current and voltage in bus bars 23 are shown by an ammeter 3| and a volt meter 32 suitably connected to the bus bars by pairs of

wires

33 and 34,-, respectively.

A plurality of thermo-couples 35 are embedded in the sand of the mold adjacent the ends of existing at the places where such thermo-couples .are disposed. While there are shown a number parts of the casting in order that the temperatures may be maintained substantially uniform throughout the body of the casting. As is seen in Figs. 7 and 8, there is a thermo-couple 35 adjacent each part of the casting whereof the temperature is to be controlled by one of the poles l0 and by means of these thermo-couples the operator is apprised when the correct temperature is being maintained or whether it should be increased or reduced, and in accordance with the requirements he will manipulate the switches .30 to augment the current through a coil H! or reduce the same. The indicating instruments 36 are of a well known type having'a, settable element to indicate the temperature that should be maintained and it is therefore necessary merely to observe whether the index moved by the current from thermo-couples 35 corresponds with its cooperating set indicating element. A gang shaft 31 for setting simultaneously these elements is indicated on panel 28 and is operable through bevel gears 38 and a suitable hand wheel or other device connected to the bevel gears.

In some cases it may be'necessary or desirable to insert the end of the pole l0 within the molding flask to secure less reluctance in the magnetic circuit and a greater field intensity in the metal .to be heated. This is accomplished as shown in Fig. 5 wherein the flask is designatedby 39 and the metal of the adjacent part of the casting by 40; To permit the molds to be made up on a molding machine and the later insertion of poles Ill without disturbing the mold, I provide a boot 4| adapted to flt over the opening in the flask and receive the end of pole Ill. The penetration of the pole l0 into the mold may be varied by using any necessary number of spacers 42 between the boot and the flask. The general arrangement of the equipment when so used is shown in Fig. 4 wherein the same reference characters denote the'same parts as in Fig. 5. In Fig. 6 the mold is not penetrated by the poles.

Fig.7 shows the ring and poles supported upon legs 43 to position the poles properly with respect to a tall casting. Incases where it may be necessary to heat a. relatively wide belt, the rings with their poles may be stacked one upon the other, bosses 44 being provided upon the upper surfaces of the rings to position the legs 43 which may be pipes adapted to fit over such bosses.

In Fig. 8 adisk-like casting 45, together with.

'which spread the magnetic field over a greater area.

After the mold is made, the flask is positioned within the-ring 9 to dispose the poles l0 opposite the lighter parts of the casting to secure localized heating of such parts. While for the purpose of simplicity of illustration I have shown the poles supported in substantially a common annular zone, the ring 9 may be laterally off-set in any manner to apply the heat as required to any given casting, or the poles may be connected together in various other ways to complete the magnetic circuit. When the casting has been poured it will frequently be found desirable to apply heat by my apparatus to keep the metal fluid until the dross tice.

I -2,o4u,s7c ments 36 on panel 28 showthe temperatures I and gases have risen to the upper portion of the metal, which will result in much stronger and sounder castings. The asting is then allowed to begin to cool; meah hile, the operator keeps careful check upon the temperatures of the various parts of the casting. When it is observed that one part is cooling more rapidly than some other part, heat is applied to maintain the temperature of the more rapidly cooling part, and the heat so applied is progressively reduced to cause all portions of the casting to cool simultaneously and at substantially the same timerate, whereby there will be no tendency to the development of draws due to a cool part contracting away from a still molten part. It is thus apparent that with my method it is unnecessary to use chills to hasten the cooling of the heavier parts of the casting, as is common prac- Another advantage of my method is that castings of any size may be poured successfully. As practiced heretofore it has been necessary to make one pour of all the metal in a casting, but by the use of my apparatus the metal in the mold may be kept in a highly fluid state until any required number of pours may have been made to secure a casting of any desired size.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes, without the payment of any royalties thereon.

I claim:

1. In combination, a laminated supporting ring of magnetic material adapted to be disposed around a mold having in it a casting cavity, said ring having openings extending from the outer periphery to the inner periphery thereof, an inductive coil mounted on the said inner periphery ,with a central passage in registry with each of the aforesaid openings, a laminated pole extend ing through each of the said openings and the adjacent coil, with the end of the pole positioned to lie adjacent a predetermined region of said cavity, said coils being connectedto provide pairs of poles of oppomte magnetic polarity, and means to indicate the temperature adjacent each pole.

2. In combination, a supporting ring of magnetic material adapted to be disposed around a mold having in it a casting cavity, said ring having openings extending from the outer periphery to the inner periphery thereof, an inductive coil mounted on the said inner periphery with a central passage in registry with each of the aforesaid openings, a pole extending through each of said openings and the adjacent coil with the end of the pole positioned to lie adjacent a predetermined region of said cavity, means to supply current to each coil, said coils being connected to provide pairs of poles of opposite magnetic polarity, and means to indicate the temperature adjacent each pole.

3. In combination, a laminated supporting ring of magnetic material adapted to be disposed around a mold having in* it a casting cavity, said ring having openings extending from the outer periphery to the inner periphery thereof, an inductive coil mounted on said inner'periphery with a central passage in registry with each of the aforesaid openings, a laminated pole extending through each of said openings and the adjacent coil with the'end of the pole positioned to lie posite magnetic polarity, thermo-electric means to indicate the temperature adjacent each of said poles, said last means comprising an element to indicate the temperature it is desired to maintain adjacent each pole, and means to conof each pole piece, means to supply alternating current to each of said coils to provide pairs of poles of opposite magnetic polarity, and means to control the current supply to each-of said coils individually.

5. The combination with a molding flask having a plurality of openings through the sides thereof, of a hollow member adJacent each of said openings, said members each having an open end in registry with its respective opening and a closed end spaced therefrom to lie immediately adiacent a predetermined region of a casting cavity in said flask, a pole piece extending into each of said members substantially to said closed end, an inductive coil disposed around a portion of each pole piece, means to supply alternating current to each of said coils toprovide pairs ofpoles of opposite magnetic polarity, means to control the supply of current to each of said coils individually, a theme-couple disposed adjacent each of said poles, and temperature indicating means actuated by the thermo-electric current from each of said coils.

a. The method of making large castings that require a quantity of metal greater than one pour, 5 which comprises making a pour, setting u in the poured metal fluctuating magnetic flelds to in-v duce electric currents to maintain the temperature of the poured metal until a subsequent pour and so continuing until the required quantity 10 has been poured, thereafter maintaining the'said fields in the less massive portions only of the casting and progressively reducing the strength of the said maintained fields to cause all parts of the casting to cool simultaneously. 15

7. The method of making large castings that require a quantity of metal greater than one pour, which comprises making a pour, setting up in the poured metal fluctuating magnetic fields to 111-! duce electric currents tomaintain the temperago ture of the poured metal until a subsequent pour and so continuing until the required quantity has been poured, adiusting the. heating effect to maintain the temperature of the less massive portions, and then permitting the casting to cool. 5

8. The-combination with a molding flask adapted to contain a mold having in it a cavity, said flask having a plurality of openings through the sides thereof, of a hollow member adjacent each of said openings, said members each having an 0 open end in registry with its respective opening in the flask and a closed end spaced therefrom .within the flask adjacent the position of said cavity.

ROBERT W. BEDILION. as