US2284743A

US2284743A - Pickling agent for copper-beryllium alloys

Info

Publication number: US2284743A
Application number: US385690A
Authority: US
Inventors: Henry C Kawecki; Wayne E Martin
Original assignee: Beryllium Corp
Current assignee: Beryllium Corp
Priority date: 1941-03-28
Filing date: 1941-03-28
Publication date: 1942-06-02
Anticipated expiration: 1959-06-02

Description

. solution.

Patented June 2, 1942 BEST f i PICKLING AGENT FOR COPPER-BERYLLIUM ALLOYS Henry Kawecki, Temple, Pa., and Wayne E. Martin, Bayside, N. Y., assignors to The Berylw York, N. Y., a corporalium Corporation, Ne tion of Delaware No Drawing. Application March 28, 1941, Serial No. 385,690

6 Claims.

This invention relates to metallurgy and more particularly to pickling solutionsfor use in the removal of surface scale and oxides from copper-beryllium alloys. In the manufacture of articlescomprised of copper-beryllium alloys the cast alloy must be subjected to hot Working and heat-treatment operations prior to any cold mechanical deformation of the same and prior to such cold mechanical deformation the scale on the surface of the alloy must be removed. Frequently also the cold worked alloy must be heattreated to anneal the same, resulting in surface discolorations due to oxidation. One of the objects of the present invention is to provide an effective pickling agent for the removal of surface scale and oxides from said alloys. Another object is to provide a pickling solution that is relatively inexpensive, readily corrosive towards copper and beryllium oxides but substantially non-corrosive towards the alloy per se and a solution that is useful over substantially prolonged time intervals towards successive batches of said alloy. Still another object is to facilitate the surface cleaning of copper-beryllium alloys. Other objects and advantages will be apparent as the invention is more fully hereinafter disclosed.

In accordance ,with these objects, we .have discovered that a caustic alkali aqueous solution, particularly .a strong or concentrated caustic alkali solution containing from 25 to 50% caus In general we add only a small amount of sodium agent is deleteriously affected. For most pickling operations on cold Cu.Be alloys we prefer to maintain the caustic alkali concentration within the range 40-50%, the sodium tic alkali, such as a 50% (by weight) NaO H,

solutions towards BeO and CuO increases with increase in temperature and with increase in caustic alkali concentration up to about 50% but decreases with increase in cupric ions in the We have found that by adding an alkali cyanide to the caustic alkali solution,\ thereby providing'free cyanide ions in the solution, the cupric salts formed on solution of CuO in the alkali solution are converted into complex cuprous cyanide compounds and the solution activity of the caustic alkali solution thereby is maintained at its maximum at any given temperature and range of caustic alkali concentration.

The amount of sodium cyanide in the caustic alkali solution may be varied widely without 'essential departure from the present invention.

cyanide concentration within the range 5-l0%, and the temperature of the solution within the range 80-l00 C. a

As a modification of the present invention, the pickling solution above identified may be employed as a combined pickling and quenching bath for Cu.Be alloys. In the mechanical deformation of Cu.Be alloys, it is frequently necessary to heat treat the metal to temperatures known in the art as beta-solutioning temperatures for prolonged time intervals. Following such heat-treatments the metal is cooled rapidly to preserve the solid solution structure formed at the temperature of treatment in order to condition the metal for cold mechanical deforma tion. Such heat-treatments are frequently practiced during both hot and cold mechanical deformation and invariably result in considerable -the preceding heating step.

It is believed apparent from the above description-that the present invention may be widely varied without essential departure therefrom and all such modifications and departures are contemplated as may fall within the scope of the following claims.

2. A pickling agent for removing scale and metalo'li des from the surface of copper-beryllium cor? y mi AVAILABLE cow alloys, said agent consisting of water containing up to 50% (by weight) of a caustic alkali and up to 10% (by weight) of an alkali cyanide.

3. A pickling agent for removing scale and metal oxides from the surface of copper-beryllium alloys,,said agent comprising a caustic soda and sodium cyanide aqueous solution, the concentration of said caustic soda approximating 40-50% (by weight) and the concentration of said sodium cyanide approximating 510% (by weight).

4. The agent of claim 3, heated to temperatures approximating 100 C.

5. The method of removing surface scale and metal oxides from copper-beryllium alloys which comprises immersing the same in a pickling bath comprised of an aqueous solution containing from 25-50% caustic alkali and sodium cyanide from small but efiective amounts up to about 10%.

6. The method of removing surface scale and metal oxides from copper-beryllium alloys which comprises immersing the same in a pickling bath s comprised of an aqueous solution of caustic soda and sodium cyanide heated to elevated temperatures within the range 80100 C.

H. C. KAWECKI. W. E. MARTIN.