US2230236A - Manganese alloy - Google Patents

Description

Feb. 4, 1941. R s, DEAN 2,230,236

MANGANESE ALLOY Filed April l, 1938 Patented Feb. 4, 1941 UNITED sTATEs PATENT OFFICE Reginald S. C., assigner,

by mesne assignments, to Chicago Development Company, Chicago, lll.

Application April 1, i938, Serial No. 199,329

5 Claims.

My invention relates to alloys of manganese, and in particular to' ductile alloys containing copper, zinc and a relatively high percentage of manganese and having desirable color, mechan- 5 ical properties, corrosion resistance and other properties which make them useful in many industries.

The principal object of my invention is to produce ductile alloys high in manganese.

l Another object is to utilize manganese in relatively high proportions in alloys having the general properties of and capable of being employed in place of other alloys heretofore known which 'do not have manganese as a constituent 15 thereof.

A further object is to produce a series of alloys of manganese having lmany ofthe properties of non-manganese alloys heretofore known, but with advantages and properties not possessed 20 by such alloys.

A still further Objectis to produce manganese alloys of good working properties, alloys which are resistant to corrosion, and alloys which are capable of being'hardened by appropriate treat- 25 ment.

Other objects and features of my invention will be apparent from the following detailed description, taken with the accompanying drawing, wherein thegure is a ternary diagram showing 30 the working -properties of manganese, copper.- zine alloys. In the practicedof my invention, I use pure manganese, preferably that'prepared by the electrolytic process as described in Il. S. Bureau of 35 Mines Report of Investigations 3322. This man- 'ganese has the following typical composition: S, total, 0.276%; S, as sulphide, 47%;- Fe, .00'1%: Si, .001%; Pb, .002%; Zn, .001%; Mo, .001%; Sn, .0005%; Cu, '.0005%; Ni, ,0005%"; Co, .0005%: Ag, o .0001%; As-i-Sb, .0001%; total Ti, A1, Zr, Cr, V, U, Be, Ta, Cb, P, and rare earths, .001%; Mn, 99.7088%. y

Manganese purifled by vacuum distillation may also be used in the practice of my invention; but commercial grades made by reduction with carbon, aluminum, or silicon` are in general unsatisfactory, since the ductility of the alloys is seriously impaired. I have \not determined the exact amounts of these elements which, when 50 present in manganese, completely prevent obtain- 65 and zinc added to pure manganese, I have been (Cl. 'l5-134) able to produce ductile, useful alloys with remarkable characteristics as will be pointed out. Properties are exhibited by these alloys which have never been associated, with alloys containing appreciably large proportions of manganese.

I have found that by the use of pure manganese I can make ductile alloys of manganese, copper and zinc, containing more than 30% manganese. With regard to their working qualities these alloys fall in to two classes: Those which work both hot `and cold, and those which are brittle cold but are excellent yfor pressing or rolling at a red heat. In the figure, I have indicated by means of a ternary diagram the composition ranges where these two kinds of working properties are shown.

The corrosion-resistance propertiesof these alloysare very valuable. I have found that they fall into three classes. f

1. Alloys the corrosion resistance of Awhich is very high, and the surface of which remains bright on alternate immersion in salt water for long periods.

2. Alloys resistant yto atmospheric corrosion but showing a surface etch onv alternate immersion in salt water.

3. Alloys resistant to atmospheric corrosion -but forming a black coating of MnOz on alternate immersion in saltwater.

I'he ternary diagram in the figure indicates the composition ranges in which these alloys have the several types of corrosion resistance. I have found that relatively small percentages of nickel may be added to these alloys with some improvement in mechanical properties and corrosion resistance. In the figure. the shaded portion marked "A identifies alloys of Class l hereinabove referred to, while the shadedportion B identiiies alloys of Class 2 hereinabove referred to. Those alloys falling within the composition range of the manganese-copper-zinc system herein identified and claimed falling outside of the shaded portions A and B come within. the third cla of lalloys identified immediately hereinabove.

These manganese-copper-zinc alloys have many uses in the arts, being suitable inl general for the purposes for which such alloys as brass, nickel-silver, and Monel metal are conventionally used. Alloys of Class A are particularly suitable for 'condenser tubes, hot water heaters, and similar' uses where resistance to corrosion by salts in solution is important.

Themechanical properties of manganese-copper-zinc alloys made in accordance with my in- Tensile strength, y Iba/sq. in. Number Nga' Zinc (ig: Nickel g l Cold -Annealed worked As' a general rule, within the cold working range the increase of manganese to copper ratio produces a softer and more ductile alloy, while the increase of copper and the addition of nickel produce a tougher alloy and one which Work hardens to a greater degree. For purposes of comparison it may be noted that alloys 2 and 3 in the above table have practically the same tensile strength as yellow brass in the annealed state; but these alloys are more duc ile and with 50% reduction have a tensile strength of 125,000 1bs./sq. in. as compared to 100,000 ibs/sq. in. for brass. On the other hand, alloy 4 in the above table has a tensile ,strength approximately that of annealed nickelfsilver, but on cold working reaches 90,000 lbs./sq. in. as compared to 65,000 1bs./sq. in. for nickel silver. On the `other hand, alloy v 5 has much the same tensile strength in the cold worked and annealed states, respectively, as Monel metal. All of these alloys are much more ductile than brass or nickel silver.y

-The alloys of the hot forming class are not generally sufliciently ductile' for satisfactory cold working; on hot pressing, however, they have the necessary strength and ductility for all practical In the specication and claims it is clear that, Where I refer tofmanganese, Ijmean pure manganese.. except where the context clearly indi-v cates otherwise. The specification in general identifies what I mean by pure manganese, but, for the further assistance of those skilled in the art, I may add that the manganese employedshould be at least about 99.5 percent pure and preferably vabout '99.7% pure; it being obvious that those impurities which are identical with certain of the .alloying constituents employed, for example, copper. zinc, and nickel, will not deleteriously aect the nal result, and in general in anotherwise pure manganese may be disregarded. Y

What I claim as new and desire to protect by Letters Patent of the United States is:

1. A dctile and corrosion-resisting alloy comprising 2 to 30% zinc, 5 to 40%v copper, and the balance pure manganese.

2. A corrosion-resisting alloy suitable for'hot working, comprising 30 to 60% zinc, l0 to 40% copper, and the balance pure manganesavsaid manganese comprising atleast 30% ofthe alloy.

3. An alloy resistin'gcorrosion by alternate immersion in salt solution, consisting of pure manganese alloyed with zinc and copper in such proportions that the final alloy has a composition within the range cross-hatched in the gure.

4. A ductile alloyl of copper, zinc and manganese, containing from 8% to 35% copper, from 2% to 50% zinc, and substantially all of the revmainder being a highly purified manganese, said manganese containing not more than 0.1% by weight of any one of the elements iron, carbon,

total amount ofk copper and zinc not being greater v than REGINALD S. DEAN.

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