US2130996A - Copper-zmcontom-manganese allot - Google Patents

Description

Patented Sept. 20, 1938 UNITED STATES corlElt-zmcoNl l xf -fia hGANltSE ALLOY PATENT OFFICE Franz R. House] and Earl I. Larsen, Indi Ind Indianapolis, Ind., a

No Drawing.

15, 1937, Serial assig'nors to P.

B- Mallory & Co., Inc;

corporation of Delaware Original application September Divided and this 4Claims.

This invention relates to copper alloys.

This case is a division of our co-pending application S. N. 164,032 filed September 15, 1937.

An object of the invention is to improve the characteristics of such alloys.

Other objects of the invention will be apparent from the following description taken in con-- nection with the appended claims.

' The present invention comprises the combi-,

nation of elements, methods of manufacture, and the product thereof broughtout and exemplified in the disclosure hereinafter set forth, the scope of the invention being indicated in the appended claims.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the combination of elements without departing from the spirit of the invention.

The present invention relates to the improvement of alloys of copper with manganese by the addition of zirconium thereto.

According to the present invention, an alloy is made containing copper, manganese and zircomum 'in substantially the preferred proportions:

, Per cent Manganese 0.1 5 Zirconium 0.05-5 Copper Balance.

It is possible, likewise, to improve the charac teristics of other copper alloys containing manganese together with small percentages of addltional ingredients, by the addition of zirconium.

For example, these alloys containing small proportions or even up to several percent of zinc, tin, calcium, lithium, magnesium, beryllium, silicon, phosphorus and silver, may be improved by the addition of zirconium in substantially the proportions indicated above. Although the cost of the alloy is thereby increased we have found that for some uses, the addition of beryllium in an amount from 0.05 to 3% is particularly beneficial.

A preferred method of alloying. is to prepare a hardener alloy, containing a high percentage of zirconium, and then introduce a predetermined amount of this alloy into a coppermanganese melt of the desired composition.

After the alloy has been prepared, according to such methods, a heat treatment may be carried, out as follows:

The alloy in the form of a billet or a sand casting or any other form,-is raised in temperature to above 700 C. The alloy is then cooled quickly after quenching, and

(quenched) from this high temperature and subsequently aged at a temperature below I00" C.

The alloys may be cold worked after aging to further improve their characteristics. In some cases, however, it has been found advantageous to introduce ately after quenching and before aging.

If the alloys are subjected to a heat treatment after they have been cold worked, a phenomenon occurs which is usually called recrystallization. Under certain conditions, the material might increase in grain size very considerably. Such increasein grain size will weaken the structure and the material will not flow very readily in deep drawing operations. Zirconium has been found to be a most effective grain reducing element, and at the same time, being responsible for the age hardening improvements connected with the heat treatment. An example of an alloy of the The maximulllm Rockwell B hardness after straight aging is Rockwell B. The electrical conductivity is 18%. If cold work is applied before aging, the maximum hardness can be raised to 88 Rockwell B. Cold working after complete aging will raise the hard- Boss to 85 Rockwell B. It will be noted that the electrical conductivity is very low in this case. However, for some applications, the conductivity is unimportant.

The zirconium raises the annealing temperature and at the same time provides a very fine grain structure which is particularly desirable if the material is to be worked into sheets.

The alloys of the type described are well suited for use at comparatively high temperature, since hardness and electrical conductivity are maintained for indefinite periods at aging temperatures indicated.

Although the preferred proportions of manganesehave been given as 0.1 to 5%, higher proportions of manganese are also permissible and come within the contemplation of this invention, namely up to 30% manganese. Manganese forms an alpha solid solution with copper throughout this range.

The most suitable range for electrical and other purposes is substantially as follows:

Per cent Manganese 1-5 Zirconium 0.5-2 Copper Balance the cold working operation immedia While the present invention, as to its objects and advantages, has been described herein as carried out in specific embodiments thereof, it is not I 3.,An alloy-composed of 0.05 to 5% zirconium,

0.1 to 5% manganese and the balance substantially all copper, characterized by high hardness and low electrical conductivity, and further characterized bythe fact that its hardness and conductivity are not permanently afiected by elevated temperatures.

4. An alloy composed of 0.5 to 2% zirconium,

, 1 to 5% manganese and the balance copper.

FRANZ n. HENSEL. EARL I. LARSEN.