US2228310A - Method for producing beryllium alloys - Google Patents

Description

Patented Jan. 14, 1941 Herbert Gruber, Werner Hessenbruch, and Wilhelm Rohn, Hanan, G

ermany, asslg'nors to Heraeus-Vacuumschmelzej A. 'G., Hanan-onv 1 the-Main, Germany No Drawing. Application March 13, 1939, Serial No. 261,649. In Germany March 25, 1938 8 Claims (01. 7545:)

This invention relates to a method for producing beryllium alloys, more particularly alloys of beryllium with heavy metals, especially with copper. 1

It is known that beryllium alloys of this type can be produced by reducing beryllium oxide with carbon in the presence of a molten bath of the metal with which the beryllium is to be alloyed. For example, the bath may be composed of 10 copper, or a metal of the iron group (iron, nickel,

cobalt) ora metal of/the chromium group (chromium, molybdenum, tungsten, uranium), or a molten bath containing a mixture or an alloy of several of these metals may be used. 1 One of the most important berylliumheavy metal alloys is the copper-beryllium type. and by following the above general procedure, using copper for the molten bath, an alloy may be produced having aberyllium content anywhere up to about 3.54%. However, difliculties are. encountered when attempts are made to operate in a manner to produce a beryllium-copper, alloy having a higher beryllium content. For economic reasonsit is desirable to be able to produce a higher-percentage beryllium master alloy, which could then be employed for the production of beryllium-copper alloys having lower beryllium content, for instance\ irom about 1.5 to about 2.5%, by diluting with more copper. I It has been known that beryllium-copper alloys of the type having a percentage of beryllium up to about 3.5 to 4%, may be produced by the thermic reduction method briefly described above, 1 the alloys being practically carbon-free, especially it after the reduction is ended the excess carbon is caused to rise by twirling or spinning the metal bath, in the general manner in which kish graphite is removed. Certain of the difllculties which are encountered when attempting to produce beryllium-copper alloys having a beryllium percentage above about 4%, are not encountered when operating with a molten bath of. one or more of the metals nickel, cobalt and iron. With these metals 4; of the iron group, especially with nickel or cobalt,

an alloy containing from about 12-15% beryllium, balance nickel or cobalt, may eilectively be produced. The operating costs involved in this procedureare substantially the same as those for the production of a 24% beryllium-copper alloy, and

' therefore theproductlon costs of a given weight of beryllium content in the beryllium-nickel alloys are less than in the case or the berylliumcopper alloys. However. it has been found that in producing a beryllium-nickel alloy, substantial quantities of carbon remain dissolved, this diiliculty being especially noticeable .when the reaction takes place in air. While the quantity of dissolved carbon can be reduced by remelting the, alloy in the 5 presence of further beryllium oxide, and prefer- -ably under reduced pressure, this procedure is disadvantageous since a considerable loss of beryllium results due to the fact that beryllium and beryllium carbide evaporate. In consel0 quence, removing the dissolved carbon in this way results in a drop in the beryllium content from the initial quantity of about 12-15% down to about 5-7 With the foregoing difficultiesin mind, the 15 present invention contemplates production of a beryllium-heavy metal alloy, especially a beryllium-copper alloy, by first reducing beryllium oxide with carbon in the presence of a molten bath of nickel, cobalt'or iron, to produce a beryl- 0 lium-nickel alloycontaining, for example, from 12-15% beryllium. In producing a berylliumcopper alloy this beryllium-nickel alloy is then diluted with a substantial quantity of copper, which has the eflect of precipitating the dissolved 25 carbon. I

The amount of dilution necessary in most instances to accomplish the precipitation of the carbon is from about 35-40%, although for'most purposes it is found desirable that the copper 30 should heavily predominate in the final alloy, the copper being preferably in excess of The reduction of the beryllium oxide in .the

.presence of the molten bath may take place in air, or in the vacuum chamber, or in the hydrogen 35 atmosphere. If desired, lime, or calcium carbide or other similarfiuxes may be used.

It should also be noted that it is not necessary to employ. pure beryllium oxide in carrying out the reaction. The beryllium oxide may be pres- 40 cut in the form of ore, ,in which event other oxides may be present. The beryllium oxide may be mixed with the carbon in the form of graphite or in the form of a carbide, especially beryllium carbide, and this mixture then introduced intcr 45 the molten bath.

The amount of copper added to dilute the alloy first produced (for instance the beryllium-nickel alloy) may be such as to produce a beryllium content from'about .3-10%. In most instances, how- 50 ever, it is preferable that the dilution should be sufllcient to result in a copper content well over 75%. a 7

As an example, a beryllium-nickel alloy may first be produced containing 15% beryllium, and

this alloy then diluted with about seven times its weight of copper, thereby resulting in an alloy containing about 87.5% copper, about 2% beryllium, and the balance nickel. An alloy having the beryllium and nickel percentages of about the order just indicated, is found to have physical properties essentially equivalent to a comparable alloyof beryllium and copper alone, especially with respectto high mechanical hardness, elasticity, and wear and fatigue resistance. The alloy containing .nmliel" (inaddition to the beryllium and copper) ,can be heat treated by precipitation hardening in much the same way as pure beryllium-copper alloys, 1. e. by quenching from temperatures between about 600 and 80 0 C. and

then annealing at temperatures between about 250 and 400 C. i

As another example of the application of the invention, reference is made. to the use of a.

molten cobalt bath, for the purpose of producing first a beryllium-cobalt alloy and then diluting this alloy with copper, the operation being car- -ried out, for instance, to result in a beryllium content of about .4% and a cobalt content of about 2.6%, copper representing the balance. Alloys of this general class are outstanding for certain purposes because of possessing particularly high hardness, coupled with good electrical conductivity, making them especially suitablefor welding electrodes, switches, contact parts and the like.

It will be apparent also that various mixtures of nickel, cobalt and iron may be used, depending upon .the purposes for which the-alloy is being prepared. Similarly, the extent of dilution with copper will vary in accordance with the properties desired. 4

In instances where it is desirable to have silicon present in the alloy in addition to the beryllium, the invention contemplates addition of silicon either to the molten bath initially or simultaneously with the beryllium oxide. Since silicon reduces the solubility of carbon in metals of the iron group, when using a molten nickel, cobalt or iron bath, very little if any carbon remains. The addition of silicon is also advantageous because it reduces the melting point of the master alloys produced in view of which such master alloys will dissolve more rapidly and easily in a moltenbath of copper which may be used for dilution.

As an example. of the use of silicon, reference may be made to the production ofan alloy suitable ior welding electrodes, in which a silicon content in the neighborhood'of 5% is desirable, Thus, when producing an alloy for welding electrodes having in the neighborhoodof .5% beryland thereby nickel, or cobalt, or iron base alloys may be obtained, which are very low in carbon.

In all examples according to the invention, it is possible to produce an initial alloy having high beryllium content which initial alloy may subsequently be fdiluted, the dissolved carbon being reduced eitherat the time of reduction (by the addition of silicon) or at the time of dilution (by dilution with copper).

We claim:

1. The method of producing a substantially carbon-free alloy containing beryllium'and copper and in which the copper heavily predominates overthe other ingredients, which method includes bringing into reaction beryllium oxide andcarbon in the presence of a molten bath of a metal chosen from the group consisting of nickel, cobalt and iron to produce an alloy of beryllium and said metal and in which carbon is also present, thereafter diluting the alloy with copper in an amount providing a copper content of at least 35%, to precipitate the carbon remaining in the alloy; from said reaction.

2; The method of producing a substantially carbon-free alloy containing beryllium and copper and in which the copper heavily predominates over the other ingredients, which method includes bringing into reaction beryllium oxide and carbon in the presence of a molten bath of a metal chosen from thegroup consisting of nickel, cobalt and iron-to produce an alloy of beryllium and said metal in which the beryllium constitutes from about 12-15%, and thereafter diluting the alloy with copper inan amount between that lower limit which will provide an alloy containing at least about 35% copper and that upper limit which will provide an alloy containing at least about .3% beryllium.

,3. The method of producing a substantially carbon-free alloy containing beryllium and copper and in which the copper heavily predomi- -with copper in anamount such that the copper constitutes at least 75% of the alloy.

4. The method of producing a substantially carbon-free alloy containing beryllium and copper and in which the copper heavily predominates over the other ingredients, which method includes bringing into reaction beryllium oxide and carbon in the presence of a molten bath of a metal chosen from the group consisting of nickel, cobait and iron to produce an alloy of beryllium and said metal in which the beryllium constitutes in the neighborhood of 12-15% of the alloy, and thereafter diluting the alloy with copper in an amount suflicient to reduce the beryllium content to a percentage of the order of 2% 5. The method of producing a substantially carbon-free alloy containing beryllium and copper and in which the copper heavily predominates over the-other ingredients, which method includes" bringing into reaction beryllium oxide and carbon in the presence of a molten bath of cobalt to produce a beryllium-cobalt alloy in which the cobalt heavily predominates and in which a substantial amount of carbon is also present, and thereafter diluting the alloy with copper to precipitate the carbon and to reduce the-beryllium content to a percentage of the orderof.4%. 6. The-method of producing a substantially carbon-free alloy containing beryllium and copper and in which the copper heavily predominates over the other ingredientsfwhich method bringing into reaction beryiiium and carbon in the presence of a molten bath of a metal chosen from the group consisting of ni'ckel, cobalt and iron and also in the presence of silicon to produce an ,alloy of beryllium, silicon and the metal of said grpup in which the beryllium constitutes from about 12-15%, and thereafter diluting the alloy with copper in an amount between that lower limit which will provide an alloy containing at least about 35% copper and :the presence of a molten bath of a metal chosen 4 from the group consisting of nickel, cobalt and iron and also in the presence of a quantity of silicon approximately equal to the quantity of beryllium to be reduced in the metal of said group to produce an alloy of beryllium, silicon and the metal of said group in which the beryllium constitutes from about 12-15%, and thereafter diluting the alloy with copper in an amount between that lower limit which will provide an alloy con .taining at least. about 35% copper and that upper limit which will provide an alloy containing at least about .3% beryllium.

8. The method of producing a substantially carbon-free alloy of beryllium with a heavy metal in which the heavy metal content heavily predominates over the other ingredients, which method includes bringing into reaction beryllium oxide and carbon in the presence of a molten bath of a metal chosen from the group consistingof nickel, cobalt and iron and also in the presence of silicon to produce an alloy of beryllium, silicon and the metal 0! said group very low in carbon in which the beryllium constitutes from about 12-15%, and thereafter diluting the alloy with a heavy metal in an amount between that lower limit which will provide an alloy containing at least about 35% or said heavy metal and that upper limit which will provide an alloy containing at least about 3% beryllium.

HERBERT GRUBER. WERNER. HESSENBRUCH.