US2173254A - Copper alloy - Google Patents

Description

1 Patented Sept. 19, 1939 COPPER armor Franz R. 'Hensel and Earl I. Larsen, Indianapolis,

Ind., assignors to P. R. Mallory & (20., Inc., Indianapolis, Ind., a corporation'of Delaware No Drawing. Application February 24, 1939,

Serial No. 258,184

1 Claim.

This invention relates to alloys and more particularly to copper base alloys of improved characteristics.

An object of the invention is to improve the 5 electrical characteristics of the alloy such as its electrical conductivity.

Another object of the invention is to improve the pouring qualities and handling characteristics of the alloy during foundry treatment and later operations.

Another object is to reduce the formation of beryllium oxide and reduce die and tool wear in machining or fabricating the alloy.

A still further object is to improve the bearing ides from the alloy.

qualities of the alloy by eliminating abrasive ox- Other objects of the invention will be apparent from the following description taken in connection with the appended claim.

The present invention comprises the combina- While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the methods of procedure and the combination of elements without departing from the spirit of the inven- 30 tion.

either binary copper-berylliumalloys or ternary or quaternary alloys having copper-beryllium as a base. These alloys can be heat treated, such heat treatment consisting of quenching and subsequent aging operations. Under certain cooling conditions one of these operations may be eliminated. By regulating the beryllium content in this type of alloy and by selecting additional alloying ingredients, a great variety in properties can be obtained both in tensile and. electrical 45 properties.

The disadvantage of such alloys has been that during melting and pouring of such alloys an excessive amount. of beryllium oxide has been formed. Beryllium has a much greater aflinity for oxygen than copper and it will therefore reduce copper made and form beryllium oxide. In order to prevent the formation of beryllium oxide, it has been necessary to melt and pour these alloys in vacuum in order to exclude oxygen from being in contact with the molten metal. These melting and pouring procedures in vacuum are I very cumbersome and expensive.

The present invention contemplates the elimination of abrasive oxides and at the same time the improvement of electrical conductivity of 5 copper-beryllium base alloys which comprises adding from .005 to 3% of lithium to the copperberyllium base alloys in the molten state so that suflicient residual lithium remains to insure that the final product contains lithium, preferably 10 in the following proportions .002 to .1%.

The preferred finished alloys may have the following compositions:

Per cent Beryllium .05 to 3 Lithium .002 to .1 Copper Balance The copper, in some cases, may be replaced in 1 part by small proportions of one or more diluent Balance substantially all copper alloying metals.

Below are givena. number ofsuitable compositions of alloys made in accordance with the present invention:

v Per cent Beryllium 2.25 Lithium I .005

Balance substantially all copper 8o Per cent Beryllium .5 Cobalt 2.25 Lithium I .003 Balance substantially all copper q 7 Percent Manganese 1. 40 Beryllium' .5 lithium v .005 Balance substantially all copper Per cent Cadmium 1 Silver Beiyllium .25 Lithium .003

There are a great number of other combine.- tions in which the addition of lithium in the proportions specified will produce the same superior qualities.

a certain desired percentage.

From the compositions it is evident that the present invention does not contemplate the addition of lithium merely for use as a deoxidizer during manufacture. it being intended that sufficient lithium be added to the copper base to insure that the residue thereof retained in the copper base alloy does not amount to less than For deoxidizing purposes only it is possible to add other elements of the alkali or earth alkali groups such as sodium, potassium, calcium, strontium or barium.

In carrying out the present invention the alloy may be made according to the following procedure-copper is melted down first. To the molten copper a quantity of from .005 to .370 of lith-' ium is added. The quantity of lithium depends on the amount of oxygen, nitrogen, sulphur, phosphorus and other impurities contained in the copper and on the type of furnace used and the melting conditions. .The stronger aflinity of lithium for impurities causes the latter to separate out from the bath before any lithium alloys with the copper. The beryllium is added in the form of beryllium-copper master alloy which usually contains 2 to 5% of beryllium and in certain cases up to 10%. In order to obtain complete freedom from oxide inclusions or other impurities, it is advisable to add a definite percentage of lithium just before pouring. The completed alloy may be cast in any form such as sand castings, billets or plates.

In the further treatment of the alloy it may be first heated to a temperature above 600 C., quickly cooled and then reheated to a temperature below 600 C. for a period from a few minutes to many hours, depending on the temperature, composition and esults desired. The alloys may also be cold worked.

In forming the new copper-beryllium base alloy of the present invention, it was found that the toughness of the material was greatly increased of the main objectionable features in processing of beryllium base copper alloys was eliminated. It was also found that in machining of castings thattool wear was greatly reduced by-using the new and improved alloy.

In foundry practice it was found that lithium will protect the beryllium from burning out when the molten alloy is heated to high temperatures.

Alloys of the type described are well adapted for the production of current carrying members, resistance welding electrodes, parts which require high thermal conductivity, contacts, contactors, bearings, springs, parts which must withstand abrasion and corrosion, trolley wire, soldering iron tips and the like.

While the present invention and its objects and advantages has been described herein, as carried out in the specific embodiments thereof, it is not desired to be limited thereby but it is intended to cover the invention broadly within the spirit and scope of the appended claim.

What is claimed is:-

85. A copper base alloy containing .05 to 3% beryllium, .002 to .'1% lithium and the balance-substantially all copper.

FRANZ R. HENSEL. EARL I. LARSEN.