US2166701A - Method of forming bearing surfaces - Google Patents

Description

Patented July 18, 1939 METHOD OF FORMING BEARING SURFACES Irving T. Bennett, Rome, N. Y., assignor to Revere Copper and Brass Incorporated, Rome, N. Y., a corporation of Maryland No Drawing. Application September 23, 1935, Serial No. 41,783

3 Claims.

My invention relates to methods of forming bearings and bearing surfaces of copper-base alloys, and particularly but not exclusively to building up and reconditioning the bearing sur- 5 faces of locomotives and other machine parts, this application being a continuation-in-part of my co-pendin-g application Serial Number 31,621, filed July 16, 1935, which is a continuation-inpart of my co-pending application Serial Number 16,816, filed April 17, 1935 (now Patent No. 2,079,- 483, dated May 4, 1937).

An excellent bearing material consists predominantly of copper containing from 2 to 20% lead and from 1 to 20% tin, with the sum of the lead and tin between approximately 4 and 40%. An excellent example of such a bearing metal is 80% copper, lead, and'10% tin.

Applicant has found that an improved dispersion of the lead in the above described bearing metal with an accompanying improvement in the desirable properties of the bearing may be secured by arc-depositing the metals of the bearing from a source of metals in which the tin and lead are not alloyed with the copper. Preferably, the carbon-arc process is employed for this purpose, although the metallic-arc process may be employed. In this connection it will be understood that the bearing and machining properties of the metal are much improved by a proper dispersion of thelead- A convenient way of performing the process is by use of a copperrcd coated in any suitable way with tin and lead, preferably in the form of a tin-lead alloy, the amounts of these three metals being proportioned in the rod to give the desired composition of the bearing metal.

The above described rod may be coated either by dipping it in or spraying it with molten tinlead alloy or by wrapping it with a tape of tinerably, however, it is coated by drawing or extruding a tube of tin-lead alloy over it. Likewise this coating operation may be performed by dipping the rod into molten tin and then into molten lead, or part of the tin may be contained in the lead if the rod is first dipped in the lead, the lead preferably containing sufiicient tin, say 1 to 5% with relation to the lead, to make it adhere to the copper rod in the absence of said rod being first coated with tin or a tin-lead alloy.

This coating may be placed on the rod in still other ways, as electro-depositing successive layers of tin and lead thereon, and, in general, the

composite rod may be formed in any of the ways lead alloy or separate tapes of tin or lead. Pref-.

of making such rods known to those skilled in the art.

The copper body of the rod may be either cop-- per or copper containing a deoxidizer such as 0.005 to 0.25% phosphorus, or0.05 to 0.5% silicon. 5 Likewise, if desired, all or part of the tin may be alloyed with the copper, but if the body of the rod is to be produced by hot working the amount of tin therein should not exceed approximately 5%.

The above described bearing metal is not hot workable, and heretofore it and thestock therefor have been produced by expensive casting methods. The above described process, besides producing an improved bearing metal in respect 1!! to securing an improved dispersion of the lead, has the decided economic advantage of enabling the employment of stock in the form of welding rods which can be fabricated by hot working processes. If it were attempted to deposit the go bearing metal by use of a rod composed of a copper body containing the tin and lead, a cast rod, in which it is difiicult to secure a homogeneous structure due to the shape of the rod, or an expensive cold worked rod, would necessarily have to be employed, because copper alloys containing lead within the ranges of constituents specified ordinarily cannot be economically hot worked. By employing a copper or copper-base rod which contains no appreciable amount of lead the same may be readily hot worked and afterward mechanically coated with the lead and tin or tin-lead alloy in the ways above mentioned to enable the rod and the bearing to be economically produced.

Phosphor-bronze gives particularly satisfactory results, and may be employed in the form of either a binary alloy or one containing tin. The alloys may contain 0.005 to 10 or 12% phosphorus, but not more than about 0.5% if they are to be worked cold, or more than about 0.1 to 0.25% if they are to be worked both hot and cold. The alloys may contain 0.1 to 20% tin with or without phosphorus, but they should not have more than about 15% tin if they are to be worked cold or more than about 5% tin if they are to be worked both 5 hot and cold. A suitable rod having this type of alloy may consist of a hot workable body consisting of copper with up to 0.1% phosphorus coated with tin-lead alloy, say with-25% with relation to the copper of :50 solder to produce the above described bearing metal having 10% each of lead and tin, this coating preferably being formed by placing a tube of the tin-lead alloy over the phosphor-bronze rod and then drawing the tube to make it closely fit the rod. 1

It has been found that the metal of the rods above described when deposited on ferrous parts, such as steel, do not readily bond with the same on account of the presence of high amounts of lead.

Somewhere about 5% lead seems to be the maximum amount that may be present if a satisfactory bond is to be secured. With higher amounts per-base metal which bonds readily. to the ferrous material. Then the welding rod having tin and lead is deposited on this preliminary layer, the metal of such rod readily bonding with copperbase alloys.

Any of the usual copper-base welding rods whichwill bond with steel may be employed for depositing a layer on the ferrous part to be built up, prior to depositing the leaded welding rod. Such copper-base welding rods, for example, may consist of copper with a small percentage of silicon or may be a 96% copper, 3.5% silicon, 0.5% tin alloy or the like known to those skilled in the art. Preferably, this non-leaded welding rod is dep oslted by using the welding rod as an electrode, that is to say, by use of the metallic-arc process,

while, as above described, upon this preliminary layer is then superimposed the bearing metal preferably by means of a carbon-arc, it being found that the carbon-arc, particularly, acts to, disperse the'lead very finely and uniformly throughout the mass of the'deposit.

It will be understood that wide deviations may be made from the invention described herein without departing from the spirit'of the invention.

I claim:

1. The method-of forming on a ferrous part a body having a surface portion of leaded cupreous metal containing up to 20% lead which comprises building up said ferrous part with a layer bonded thereto of substantially lead free copper or copper base alloy by progressively depositing 'the same on said part from a welding rod by use of a welding operation, and afterward building up said layer with a second layer bonded thereto of said leaded metal by progressively depositing on said first mentioned layer by the electric arc the metal of awelding rod which is predominantly copper and contains said lead.

2. The method according to claim 1 in which the first mentioned welding rodis deposited by the electric arc.

3. The method according to claim 1 in which the first mentioned welding rod is deposited by the electric arc employing the welding rod as an electrode, and in which the second mentioned welding rod is deposited by use of a carbon arc.

IRVING T. BENNETT.