US3633866A

US3633866A - Apparatus for cladding metal

Info

Publication number: US3633866A
Application number: US7329A
Authority: US
Inventors: Charles F Funk
Original assignee: SHAPEWELD Inc
Current assignee: SHAPEWELD Inc
Priority date: 1970-01-14
Filing date: 1970-01-14
Publication date: 1972-01-11
Anticipated expiration: 1989-01-11

Abstract

In the metal-cladding method disclosed a body of molten metal is located above the surface of the base metal to be clad. The metal is allowed to flow downwardly toward the surface through a restriction that shapes the metal striking the surface into an elongated narrow stream. The stream is about as long as the longest dimension of the surface being clad. The apparatus of the invention includes a mold having a crucible to hold the molten metal and a slot for restricting the flow of the molten metal into the mold cavity enclosing the surface being clad. The slot shapes the metal into an elongated, narrow stream that is about as long as the longest dimension of the surface being clad.

Description

ilite States Patent lnventor Charles F. Funk Metairie, La.

Appl. No. 7,329

Filed Jan. 14, 1970 Patented Jan. 11, 1972 Assignee Shapeweld, Inc.

New Orleans, La.

Original application Sept. 18, 1967, Ser. No. 668,486. Divided and this application Jan. 14, 1970, Ser. No. 7,329

APPARATUS FOR CLADDING METAL References Cited UNITED STATES PATENTS l/1936 Greene et a1.

24g 10s x Primary Examiner-J. Spencer Overholser Assistant Examiner-V. K. Rising Attorney- Hyer, Eickenroht, Thompson and Turner ABSTRACT: In the metal-cladding method disclosed a body of molten metal is located above the surface of the base metal to be clad. The metal is allowed to flow downwardly toward the surface through a restriction that shapes the metal striking the surface into an elongated narrow stream. The stream is about as long as the longest dimension of the surface being clad. The apparatus of the invention includes a mold having a crucible to hold the molten metal and a slot for restricting the flow of the molten metal into the mold cavity enclosing the surface being clad. The slot shapes the metal into an elongated, narrow stream that is about as long as the longest dimension of the surface being clad.

PATENTEU m1 1 1972 3633866 CHARLEj F. FUNK I N VENTOR.

,4 TTOENE7'3 APPARATUS FOR CLADDING METAL This is a division of application Ser. No. 668,486, filed Sept. 18, I967, and entitled Method and Apparatus for Cladding Metal." I

This invention relates to a method of and apparatus for cladding the surface of a metal body with a layer of metal.

There are many instances where it would be desirable to add to or rebuild the surface of a body of metal. For example, wear plates and hammers wear away in use and have to be replaced. If their worn surfaces could be restored to their original dimensions economically, a large savings could be realized. One method thathas been used in the past to accomplish this is electric are welding. In this process, successive passes are made over the worn surface with an electrode to fuse a layer of metal to the surface. This process is costly because it is time consuming, and is only economically feasible when a very thin layer of metal is to be added.

Another method employed is to pour a quantity of molten metal over the surface of a body of base metal. The molten metal is supposed to supply the heat to fuse the added metal to the surface being clad as it solidifies. This method has been unsatisfactory in the past because complete fusion was seldom, if ever, obtained between the added or clad metal and the base metal. Further, the depth of fusion often varied considerably. On the areas where little or no fusion existed, the clad metal layer would chip off in service, causing additional down time and expense, with the result that no savings are realized in the attempt to reuse the worn, rebuilt member.

It is an object of this invention to provide apparatus for and a method of cladding the surface of a metal body that consistently produces complete fusion between the clad metal and the surface being clad.

It is another object of this invention to provide apparatus for and a method of cladding the surface of a metal body that produces substantially uniform fusion of the clad metal to the base metal along the entire length of the surface being clad.

These and other objects, advantages, and features of the invention will be apparent to those skilled in the art from a consideration of this specification, attached drawings, and appended claims.

The preferred embodiment of the apparatus for practicing the method of this invention will now be described in connection with the attached drawings in which,

FIG. 1 is a cross-sectional view of the apparatus set up to clad the surface of a worn hammer from a hammer mill;

FIG. 2 is a view on an enlarged scale taken along line 2-2 of FIG. I; and

FIG. 3 is a view along line 33 of FIG. 1.

In FIG. I the apparatus is set up to rebuild worn hammer 10, a typical hammer from a hammer mill. The end of the hammer has been worn away sufficiently to require the hammer to be removed from the mill. The portion of the hammer remaining is undamaged. Therefore, if the metal that has been worn off could be replaced, the hammer could be used again.

Preferably, before the cladding operation is begun, the worn end of the hammer is cut off to present square smooth surface 12 to which the clad metal may be fused. This is not necessary. It is desirable, however, since it allows the exact volume of metal required to restore the hammer to its original dimensions to be more accurately calculated. Also, by cutting off the end of the hammer, so that it will be substantially flat and level when placed in themold, the molten metal to be directed against the surface will flow over the surface uniformly.

Hammer is placed in mold box 14, which holds the hammer in a vertical position with surface 12 level. To hold the hammer in this position, plate 16 is fixed to the bottom of the mold box with flat side 16a vertical. Lock screw assembly 18 holds the hammer against side 16a of plate 16. The lock screw assembly includes threaded rod 18a, which extends through threaded nut 18b, attached to the side of the mold box. The rod has head 18c located on the outside of the box and provided with wrench flats so the rod can be rotated by a wrench. Rotating the rod moves it axially into and out of the mold box. The opposite end of the rod from head 18c is connected to pressure plate or shoe 19 through tall and socket joint 18d. Pressure plate 19 is moved into engagement with hammer 10 to hold it against plate 16 by rotating rod 180. Supporting the weight of the hammer is channel 20, arranged as shown in FIG. 3. A channel is used to allow the lower edges of the hammer to be fully supported even if it is necessary to have one edge above or below the other to level surface 12. Therefore, by placing hammer 10 against vertical side 16a of plate 16 and adjusting the lower end of the hammer in angle 20, upper surface 12 can be leveled and held level by the lock screw assembly.

Dividing the mold box into an upper and lower section is horizontal partition 22. The partition is provided with opening 22a, through which the hammer extends. The upper end of hammer 10 is enclosed by mold 24. The mold comprises two halves 24a and 2412, which are identically shaped so that when brought together they will appear, as shown in FIG. 1, with parting line 25 intersecting the centerline of surface 12. The mold halves are supported on fire brick 26 and molding sand 27 is placed around the bottom of the mold tohold it in position and also to keep molten metal from escaping from the mold.

It is intended that the mixture of Thermit material will be placed in the crucible and reacted in place. It will then be allowed to flow downwardly into metal-shaping section 33 of the mold. The metal-shaping section of the mold forms cavity 34 into which the upper end of hammer 10 extends. This cavity is shaped to restore hammer 10 to its original dimensions. Therefore, the distance from the end of the hammer to the upper end of the cavity is how much shorter the hammer is than it was originally.

Connecting cavity 34 of the metal-shaping section and the crucible section is passageway 36. The passageway comprises an elongated narrow slot that extends substantially the length ofthe surface to be clad. In the embodiment shown, this would be surface 12 shown dotted in FIG. 2. The purpose of slot 36 is to restrict the flow of the liquid metal from the crucible section sufficiently for the metal to flow evenly through slot 36 against surface 12 of the hammer in a long narrow stream of uniform thickness. Therefore, the width of the slot must be designed to provide this restriction. For example, when rebuilding a hammer 5% inches thick and 9 inches wide by adding 2% inches of metal to the end of the hammer, a slot substantially as long as the longest dimension of the surface being clad, i.e., 9 inches, and between one fourth and three-eighth of an inch wide has been found to give good results. These hammers, that is, these 5% by 9 inches hammers, are approximately 18% inches long when finished. On smaller hammers, for example, on hammers 1 inch thick and 3 inches wide, a slot three inches long and from one-fourth to three-eighth inch in width has been found to be satisfactory, when building up the hammers 2 /2 inches. These latter hammers are approximately 9 inches long when finished.

In the preferred embodiment, the lower end of the crucible is provided with opening 38. Inwardly extending annular flange 39, located in the opening provides upwardly facing annular shoulder 390. Metal discs (not shown) are placed on shoulder 39 to hold the Thermit material in the crucible section long enough for it to react completely and for the slag to rise to the top. The plates then melt and allow the metal to flow downwardly into the metal-forming section. Below opening 38 to lead the metal to slot 36 the mold is provided with opposed downwardly converging curved surfaces 40a and 4012.

To practice the method of this invention, the quantity of Thermit material required to provide the necessary volume of metal is placed in the crucible above the surface to be clad. The material is reacted and held in the crucible long enough for the slag to rise to the top. It then flows downwardly through slot 36 and directly against surface 12. The flow of the metal toward the surface is restricted sufficiently by slot 36 to form the liquid metal into an elongated narrow stream that is as long as the slot and substantially as long as the surface being clad. The metal is confined to the surface and formed into the desired configuration by the mold cavity above the surface.

It is believed that the substantially uniform fusion obtained between the base metal and the clad metal by the method and apparatus of this invention results in part from the shape of the elongated narrow stream of metal that is directed downwardly against the surface being clad with considerable force. The shape of the stream produces uniform turbulence in the body of molten metal above or adjacent the surface being clad and causes the entire surface to be raised to fusion temperature before any of the molten metal begins to solidify. Further, by forming the metal into a stream substantially as long as the longest dimension of the surface being clad, the distance the metal flows across the surface to reach the mold is a minimum. This reduces the amount of heat given up by the molten metal that initially engages the surface and reduces the possibility that some of the molten metal will solidify adjacent the base metal before the base metal is raised to fusion temperature.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the method and apparatus.

It will be understood that certain features and subcornbinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. A mold for using the Thermit process to clad the upwardly facing substantially horizontal and flat surface of a metal member comprising an open-bottomed metal-shaping section for encircling the upwardly facing surface to be clad having a cavity located above the metal surface to confine the clad metal on the surface in the desired shape and thickness, a crucible section located above the metal-shaping section for holding the Thermit material while it reacts and produces a quantity of superheated weld metal to fuse with the metal surface to be clad, and a passageway connecting the crucible section to the cavity in the metal-shaping section comprising an elongated narrow slot extending substantially the length of the surface to be clad to restrict the flow of superheated weld metal from the crucible section, said slot having a width such that the flow of the molten metal is restricted sufficiently to cause it to flow through the slot against the surface being clad in a stream as long as the slot to produce turbulence in the molten metal adjacent the surface being clad and to supply molten metal directly against the surface being clad along substantially its entire length, said crucible section having an opening in the bottom thereof above the elongated slot that can be closed with one or more plates to hold the Thermit material in the crucible section until the reaction is completed after which the plate will melt and allow the superheated weld metal to flow through the opening toward the slot, said mold further having downwardly converging surfaces between the opening and the slot to direct the molten metal from the opening to the slot uniformly along the length of the slot.

2. A mold for using the Thermit process to clad the upwardly facing substantially horizontal and flat surface of a metal member comprising a open-bottomed metal-shaping section for encircling the upwardly facing surface to be clad having a cavity located above the metal surface to confine the clad metal on the surface in the desired sha e and thickness, a crucible section located above the metal-s aping section for holding the Thermit material while it reacts and produces a quantity of superheated weld metal to fuse with the metal surface to be clad, and a passageway connecting the crucible section to the cavity in the metal-shaping section comprising an elongated narrow slot extending substantially the length of the surface to be clad to restrict the flow of superheated weld metal from the crucible section, said slot having a width such that the flow of the molten metal is restricted sufficiently to cause it to flow through the slot against the surface being clad in a stream as long as the slot to produce turbulence in the molten metal adjacent the surface being clad and to supply molten metal directly against the surface being clad along substantially its entire length, said crucible section having an opening in the bottom thereof above the elongated slot to serve as a gate through which the molten metal can flow from the crucible section to the elongated slot, said opening being substantially wider and shorter than the slot, said mold further having downwardly converging surfaces between the opening and the slot to direct the molten metal from the opening to the slot uniformly along the length of the slot.

Claims

2. A mold for using the Thermit process to clad the upwardly facing substantially horizontal and flat surface of a metal member comprising a open-bottomed metal-shaping section for encircling the upwardly facing surface to be clad having a cavity located above the metal surface to confine the clad metal on the surface in the desired shape and thickness, a crucible section located above the metal-shaping section for holding the Thermit material while it reacts and produces a quantity of superheated weld metal to fuse with the metal surface to be clad, and a passageway connecting the crucible section to the cavity in the metal-shaping section comprising an elongated narrow slot extending substantially the length of the surface to be clad to restrict the flow of superheated weld metal from the crucible section, said slot having a width such that the flow of the molten metal is restricted sufficiently to cause it to flow through the slot against the surface being clad in a stream as long as the slot to produce turbulence in the molten metal adjacent the surface being clad and to supply molten metal directly against the surface being clad along substantially its entire length, said crucible section having an opening in the bottom thereof above the elongated slot to serve as a gate through which the molten metal can flow from the crucible section to the elongated slot, said opening being substantially wider and shorter than the slot, said mold further having downwardly converging surfaces between the opening and the slot to direct the molten metal from the opening to the slot uniformly along the length of the slot.