US2408342A - Alloy - Google Patents

Description

'carbon-carborundum crucibles.

Patented Sept. 24, 1946 New Jersey Zinc Company; New York; NI. a corporatiomof New Jersey:

. NoDrawing. .Application Jilly 20, 1944, Serial No. 545,868

Thisinventionrelates o alloys and particularly to brass-type alloys of zinc,.'copper and manganese',.'and has; for its object' the provision of improvedalloys of this type.- 7 v The alloys of the invention 'generally resemble brassior bronze and may aptly beicalled white brasses or bronzes. The base of the alloys is made up of zinc, copper and manganese, and their characteristic new and improved properties are due to the presence of a small amount it Claims. (01. ts -1 57,5

of beryllium. In addition to imparting other desirable physical properties to the alloys, bery1lium.

beryllium; are'first-melted together and brought to a; suificiently high temperature so as not to freeze when the other alloying constituents arelater' added. The manganese is then added in small: lots until all of the addition has dissolved.

At this stage, it is expedient to'add a smallamount of borax to clear up any oxide on the surface of the molten metal (melt). The amount of borax is preferably less than requiredto 'form' a continuous molten'cover, the ideal condition beingto'h'ave' beads'of'molt'en borax which dissolveor. flux any'surface oxide and then, gather functions as an anti-oxidant, preventing oxida-eij tion of the alloying constituents, particularly manganese, during: the production; of thealloyand during its subsequent remelt'ing'.

Thealloys of the invention; in its broad aspect, Y co'ntainJfrom to 375 zinc; from-735w near the. crucibleswall leaving a clear center portion through which other additions, may be made. After the borax has thus cleared up the surface of the melt, the zinc is added and the entire melt is stirred to produce a uniform composition'. The melt is then allowed tostand for a manganese, from 0-.005" "t'o 2%,- and 'pneferably 1,

from 0.01 to 0;5%, beryllium and thebalance (up to 77%.) substantially an: coppe'rbu than and except for the possibleinclusionof leadas hereinafter explaihed These-alloys are characterized by excellent physical pro ties such as tensile strength, tensileelongationand hardness. Particularly usefulalloys of the invention contain from- 18 to 23%-- (preferably about21%'l Zinc, from is to 20%--;(prererab1y about. 18%) manganese, .f-i 'oni- 0.01 600.2% (preferably about 0.08%) beryllium; andfi on'f riot less; than 53 up to about 67% -'(=preferably from' 57 to 61-%)* copper; Other very useful alloys of the invention contain from 20 to 25% (preferably about 22%) zinc, from 7.5 to 12.5% (preferably about 10%) manganese, from 0.01 to 0.2% (pref-. erably about 0.08%) beryllium, and from not less than 59% up to about 73% (preferably from 64 to 68%) copper.

Small amounts of lead, say from 0.1 up to 3%, may also be included in the alloys without any. substantial deleterious effect on the cast metal. Lead, as in ordinary brass, imparts to the alloy desirable properties with respect to machineability.

The alloys of the invention are preferably manufactured andhandled in clay-carborundum and Steel crucibles t less;

may be used for remelting purposes without ex- Crucibles few minutes to permit entrained oxides to reach the surface; and is then skimmed and "poured. Electrolytic. copper cathode sheet, or any other good commercial grade of. copper, may be. used in the. manufacture of the alloys of the invention. The zinc is. pref erably/ high grade. metal. containing 99.99% zinc. Electrolytic manganese, is.the preferred formv of that constituent. While. metalsof; high purity are. thus. preferably used,

alloys of satisfactory properties may be made. of 7' metals or alloys, of good commercial. purity.

, Thejalljoys of the invention melt at temperatures between about 800 and 950 C., depending largely on the copper content, the higher the cop per content the higher the melting temperature, and arehighly castable. For example, the alloy of 21% zinc, 18% manganese, 0.1% beryllium, and the balance essentially copper has a melting temperature of about 850 C., and can be cast at temperatures from 875 to over 1000 C. The preferred temperature range for casting is 875 to 925 C. This alloy can be sand cast quite easily in the standard green sand mold common to the foundry industry, using casting and molding practices common in the industry. The alloy has a high shrinkage during solidification, as have many commercial sand casting alloys, and means for handling such alloys are well understood and available in commercial foundry practice. The pattern shrinkage allowance for the alloy is T36 inch per foot. The density is 0.296 pound per cubic inch. A notable advantage of the alloy in sand casting is that the sand does not adhere to the casting and can be removed easily by shaking or by blowing. Most commercial foundry alloys must be sand blasted to remove sand burned to t eir surfaces. In addition to sand casting, the

3 alloys of the invention may be chill cast or die cast.

Alloys of the invention display excellent retention of composition during manufacture and re- 4 silver, as, for example, in the manufacture of tableware, which may be electroplated with silver.

I claim: 1. An alloy containing 15 to 37.5% zinc, 7.5 to

melting. An alloy of zinc, manganese and copper 5 30% manganese, 0.005 to 2% beryllium, and the without beryllium becomes heavily coated with balance substantially all copper but not less than a brown oxide film identified as manganous oxide 50%. (MnO), and is very difiicult to handle. The in- 2. An alloy containing 15 to 37.5% zinc, 7.5 to clusion of beryllium, as an anti-oxidant, in the 30% manganese, 0.01 to 0.5% beryllium, and the alloys of the invention effectively inhibits surbalance substantially all copper but not less than face oxidation of the alloy and loss of manganese 50%. on remelting. This is illustrated by the follow- '3. An alloy containing to 37.5% zinc, 7.5 to ing example: v 30% manganese, 0.005 .to 2% beryllium, 0.1 to 3% Four and one-half pounds of an alloy of sYnlead, and the balance substantially all copper but thetic composition 60% copper, 21% zinc, 18.5% 15 not less/than 50%. manganese and 0.5% beryllium were prepared. 4. An alloy containing 15 to 37.5% zinc, 7.5 .to The alloy was prepared by melting the copper and 30% manganese, 0.01 to 0.5% beryllium, 0.1 to a 0.2% beryllium-copper hardener together. The 3% lead, and the balance substantially all copper melt was lowered to 950 C. and zinc was added. but not less than 50%. The temperature was lowered to 900 0., and a 5. An alloy containing 18 to 23% zinc, 15 to 2" x 4" x A" slab, pigs, and water-pour were 20% manganese, 0.01 t 0.2% beryllium, and not cast. The pigs were remelted, raised to a, temless than 53% copper. perature of 900 C. and Water-pour and pigs were 6. An alloy containing 18 to 23% .zinc, 15 to cast as before. This was repeated until the alloy 20% manganese, about 0.1% beryllium, and not had been remelted a total of four times. Follow- 25 less than 53% copper. ing are the analytical data: 7. An alloy containing 18 to 23% zinc, 15 to Analysis Condition Copper Manganese Beryllium Remarks Per cent Per cent Per cent 61.7 13.9 0.08 Clean and white. 13.8 l Slightlyoxidized. 13.6 More oxidation. Third remelt 13. 3 D0. Fourth remelt 12.7 0. 01 Definitely oxidized but considerably cleaner than col-re Spending cop per-zinc-manganese alloy without beryllium.

The alloys of the invention have desirable cor- 20% manganese, 0.01 to 0.2% beryllium, 0.1 to 3% lead, and not less than 53% copper.

8. An alloy containing about 21% zinc, about 18% manganese, 0.01 to 0.2% beryllium, and not less than 57% copper.

9. An alloy containing 20 to 25% zinc, 7.5 to 12.5% manganese, 0.01 to 0.2% beryllium, and not less than 59% copper.

10. An alloy containing 20 to 25% zinc, 7.5 to 12.5% manganese, 0.01 to 0.2% beryllium, 0.1 to 3% lead, and not less than 59% copper.

11. An alloy containing about 22% zinc, about 10% manganese, 0.01 to 0.2% beryllium, and not less than 64% copper. JOHN L. RODDA.