US2166700A - Method of building up metal parts - Google Patents

Description

Patented July 18, 1939 UNITED STATES PATENT OFFICE METHOD OF BUILDING UP METAL PARTS No Drawing. Application July 16, 1935, Serial No. 31,621

7 Claims.

process effective progressively to melt the end- IBportion-s of the rod and bond the molten metal to the part, and, after the part is gradually built up in this way and cooled, to machine it to the desired shape and size.

In the attempt to condition metal parts in this way it has been found that known metals suitable for welding are diflicult to machine, especially after being subjected to the welding operation for building up the part. Further, it has been found that weld metals heretofore pro- 25 posed have the defect of presenting poor bearing metals due to the tendency of the bearing made of them to seize or grab as it is commonly termed.

Applicant has found, that by suitably incorporating uncombined lead into the metal of which thepart is built up, the, same may be readily machined, although such metal containing lead it has been found would be unsuitable for ordinary welding -purposes because lead would act a to weaken the strength of the welded joint uniting the parts welded together. Further, the uncombined lead it has been found acts to prevent socalled seizing or grabbing in the bearing, probably because its action is in the nature' 40 of a lubricant.

In the practice of the invention, the base metal of which the part is built up is such that it will not alloy with lead, in order that the lead may.

For convenience (Cl. 2l910) in this sense with lead, or with lead alloy which is in effect lead, is referred to in the appended claims as leaded cupreous metal. Satisfactory results will ordinarily be secured with appreciable amounts of lead up to about 5 or 6%, although for some uses the amount of lead may be advantageously increased up to about The welding metal, which conveniently may be in the shape of a rod, may be made by introducing lead into the melt and easing the rod, or after casting the billet cold rolling it to the desired size and shape to form the rod. In such rods the lead will be only mechanically associated with the copper or copper alloy for the reason that it will exist only as a mechanical mixture therewith, the lead being dispersed throughout the rod in the form of minute globules. However, working copper or copper alloys containing lead is ordinarily an expensive process because lead ordinarily renders such metal hot short, that is to say, such metals cannot be hot rolled or otherwise worked hot.

Conveniently, therefore, the welding rod consists of copper or a copper-base alloy which can be hot worked and has the lead mechanically associated with it in some way other than by introducing the lead into the melt of which the rod material is formed. Preferably this is done by hot rolling a lead-free copper or copper-base alloy into rods, or it may be done by hot rolling the metal into sheets, say about thick, and shearing the sheets to form rods of approximately square cross-section, the opposite sides being left rough as the result of the shearing operations. The rod, however formed, may be coated with lead by dipping it into molten metal or spraying it with it, the roughened surfaces of the rod when sheared causing a greater amount of lead to adhere than would otherwise be the case. For a rod of given weight, a square or other polygonal cross-section of the rod it will be understood provides a greater surface area for adherence of the lead than would otherwise be the case if the rod were circular in crosssection.

It will be understood that the lead may be mechanically associated with the copper or cop- 'per-base alloy in other ways as, for example, by employing tubing with a lead filler, or by wrapping the rod with lead tape, or by drawing or extruding a lead tube over the rod, or by electro-depositing a coating of lead upon the rod, or by any of the known methods of forming composite rods.

It is also possible to coat the rod with lead dust, or other forms of comminuted lead, mixed with a binder to make the lead adhere to the rod. Such a coating may be formed by mixing lead dust with a suiiicient amount of sodium or potassium silicate and water, say two-thirds potassium silicate and one-third water, to form a paste of the consistency of a rather thick paint, which paste may be applied to the rod by dipping it into the paste, or by use of a brush.

It is also possible to coat a copper rod, or one formed of a copper-content alloy, with separate layers of lead and tin, or with a lead-tin or other lead-content alloy, and upon melting of the rod the tin, or other non-lead constituents soluble in copper, will dissolve in the copper or copperbase while the lead will be distributed through the mass as a mechanical mixture with it. It is possible, when both tin and lead are present in the rod, either in the form of separate metals or as an alloy, the dispersed lead in the weld metal may contain a little tin in amount determined by the relative solubility of tin in lead and copper. However, so far as effective results have been observed, this does not reduce the efiicacy of the dispersed lead. It will therefore be understood that a lead-tin, or other alloy of lead and a constituent highly soluble in copper, will be materially if not wholly reduced to what in effect amounts to free lead. It will be understood that the amounts of lead and tin employed in these examples will be such as to incorporate into the metal deposited on the metal part the percentages of lead and tin herein else where specified, and that in this way additional lead and tin may be added to the alloy or mixture of which the body of the rod is formed when said alloy or mixture already contains these metals.

The rod also may be coated or otherwise me-,

chanically associated with a lead compound and a reducing agent to form metallic lead during the welding operation. This lead compound may consist of lead oxide or red lead, and the reducing agent may consist of lamp black or other carbonaceous substance. The lead compound and the lamp black may be mixed with a suitable binder to form a paste which may be applied to therod by a brushing or dipping operation. For example, 10 parts lead oxide may be mixed with 1 part lamp black and a mixture of potassium or sodium silicate and water, say two-thirds potassium silicate to one-third water, to form a paste. As a substitute for lamp black, colloidal graphite may be employed. As binders liquid shellac and linseed oil may be employed, which carbonaceous substances will produce a char that also will act as a reducing agent. Conveniently the lead oxide or other lead compound of which the paste is formed is in a finely divided state as, for example, a powder which will pass through an to 200 mesh screen, sufficient of a binder being employed to form a rather thick paint.

The operation of building up the metal part by use .\of the above described welding rods is performed by depositing the rod thereon by use of an electric arc. Preferably the operation is performed by arc-depositing the material of the rod by use of the so-called carbon "arc" process, although, if desired, it may be performed by use of the .so-called electric metallic arc process. Applicant has found that an improved dispersion of the lead may be secured by the use of these processes, all of them securing a much better dispersion of the lead than can be obtained by a casting process. During the welding proceses a small amount of lead is melted with the copper or copper alloy fractions of the rod being deposited and is dispersed and uniformly mixed with them to form the weld metal. For example, in depositing a lead-coated copper alloy rod by the arc process, the copper alloy at the end of the rod is gradually and progressively melted, the lead adjacent the end of the rod gradually melting with it and flowing into the are, which latter finely disperses the lead and uniformly mixes it with the copper a1- '1oy as the latter is deposited. Further it has Due to these properties and the finer structureand lead distribution a superior bearing is secured.

Preferably, but not necessarily, and without limitation thereto, the copper is in the form of a copper-base alloy containing silicon, silicon acting to secure an excellent dispersion of the lead through the metal of the built up part. Such an alloy may consist of 2 to 4.7% silicon, at least 0.1% tin throughout this range of silicon, with the balance approximately all copper. The maximum amount of tin for any value of silicon up to 3% may be as high as 2% and should not exceed this value, While when the silicon is of tin. Appreciable amounts up to 0.5% zinc,'

or in any event preferably not more than 1% zinc, may be incorporated into the alloy for improving its working qualities, and, if desired, a small amount of phosphorus may be incorporated for improving the welding properties of the rod. Appreciable results will be obtained with as low as 0.005% phosporus, and preferably the phosphorus should not exceed 0.1% with the higher amounts of silicon and tin and 0.25% with the lower amounts of silicon and tin, lest it render the metal fhot short. A satisfactory specific example of this metal is silicon 3.5%, tin 0.5%, balance copper, and, if desired, either or both 0.05% phosphorus and 0.25% zinc substituted for part of the copper. Such metal has great ductility and high strength. It works free ly both hot and cold, and has excellent resistance to corrosion. It also machines freely, and presents a good bearing surface.

If desired, the copper-base alloy may consist of binary silicon-bronze, with or without small amounts of zinc or phosphorus, or both, within the ranges of zinc and phosphorus above specified. The binary alloys with the addition of small amounts of manganese may also be employed. From 0.5 to 1.25% manganese will give satisfactory results. Bronzes of this group may above approximately 3% the maximum amount 7 contain to silicon, about 3 to 3.5% being the preferred amount. If the alloys are cast the phosphorus may be as high as ther ccppenbase alloys as, for example, br sy tin b-ronzes may be employed. Preferably the amount of tin is about 10%, but lower values, say down to 1%, and higher values, say to 12%, will give fairly satisfactory results. .osphorus also be added to these alloys, erably not more than 6.05%. However, if red, the phosphorus may run up to 1%. an is ample of a suitable alloy of this group is 10% i 12% phosphorus, balance copper.

ary copper-phosphorus welding rod may also e employed for the copper-base alloy as; for example, copper rods containing 6 to l@% phos- The tin be omitted, if desired, from the hereinbeziore described alloys of which the body of the rod is formed, and may be placed in the coating of the rod, as above described, so that the will alloy with the copper-base when the rod is melted.

if desired the alloy of which the welding rod is 25v made may contain nickel as the equivalent of silicon in respect to improving the dispersion of the lead. Up to 1% nickel will be sufiicient to disperse up to about 10% lead, and proportionate amounts of nickel may be employed for higher amounts of lead. In general, any or" the above mentioned alloys which do not contain silicon may have incorporated therein a small amount of nickel for this purpose. As little as 0.1% nickel will give appreciable results, but preferably about 1% thereof is employed as giving satisfactory results for all values of lead. It will be understood by those skilled in the art that the term welding rod is used herein in its ordinary sense as implying a rod, pencil, wire, ribbon and the like of convenient size for use in electric arc welding.

It will be understood that within the scope of the appended claims wide deviations may be made from the above described welding rods and copper-content alloys without departing from the spirit of the invention.

I claim:

1. The method of forming a leaded cupreous metal mass which comprises building up said mass on a backing by progressively electric arc depositing thereon the end fractions of a welding rod which is predominantly copper and contains appreciable amounts up to lead.

2. The method of forming a bearing surface of leaded cupreous metal comprising mechanically associating material 0! the group consisting of copper and copper base alloy with material of the group consisting of lead, reducible lead alloy and of leaded cupreous metal comprising depositing on and bonding to a metal backing, by use of an electric are, metal irom a welding rod which is predominantly copper and contains appreciable amounts up to 1.5% lead; which lead ispresent in said welding rod in the form of metal of the group consisting of lead and. tin-lead alloy of which latter the tin content does not exceed 12% of the metallic constituents of said rod the electric are being caused progressively to melt the end fractions of said rod and project and deposit them to build up said backing with said leaded metal. V

4. The method oi forming a bearing surface of leaded cupreous metal comprising depositing on and bonding to a metal backing, by use of an electric are, metal or" an elongated welding rod by causing the arc progressively to melt the end fractions of said rod and project and deposit them to build up the backing with said leaded metal, which rod is predominantly copper and contains tin and lead, the amount of tin not exceeding 12% and of lead not exceeding 15% of the metallic constituents of said rod, the lead being present in the form of metal of the group consisting of lead and tin-lead alloy.

5. The method of forming a bearing surface of leaded cupreous metal which comprises depositing on and bonding to a metallic backing, by use of an electric arc, metal from an elongated metallic welding rod comprising a leaded cupreous metal mass which is predominantly copper and contains 0.1 to 12% tin and appreciable amounts up to 15% lead, by causing the arc progressively to melt the end fractions of said rod and project and deposit them to build up said backing with the metal of said bearing surface.

6. The method according to claim 5 in which the leaded cupreous metal mass comprised by said rod also contains 0.01 to about 4.7% silicon and not more than about 2% tin.

'7. The method of forming a bearing surface comprising depositing on a backing member by the electric are a leaded cupreous metal from a welding rod containing approximately copper 89%, tin 9%, and lead 2%.

IRVING T. BENNETT.

Patent No. 2,166,700.

CERTIFICATE OF CORRECTION.

y 8, 959- IRVING T. BENNETT.

It is hereby certified that error appearsv in the printed specification of the above numbered patent requiring correction as follows: Page 1, second colunm, line 10, for the word "casing" read casting; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office Signed and sealed this 5th day of September, A. D. 1959.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.