US1869554A - Alloy - Google Patents

Description

Aug. 2, 1932.

Per ceh Ifo/7 Per cenf I ron O. W. ELLIS ALLOY Filed Dec. 14. 1925 Increase in perce/#age elonyafioh,

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INVENTOR Owen W .///ls.-

ATTORNEY Patented Aug. 2, 1932 UNITED STATES lmvr-EN'I' oFFlcla:

OWEN W. ELLIS, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIC & MANUFACTURING COMPANY, A CORPORATION- OF PENNSYLVANIA l.ALLOY Application led December 14, 1928. Serial No. 326,029.

My invention relates to alloysand more partlcularly to an aluminum brass in which iron Vand manganese have been substituted for part of the zinc.

An object of my invention is to provide an improved aluminum brass having an alpha beta or a beta struct-ure that has greater ductility and strength than previous alloys of this type.

Another object of my invention is to provide an improved aluminumA brass having an alpha beta or a beta structure in which iron, or a mixture of manganese and iron, has been substituted for part of the zinc in the l5 brass in such proportions that the ductility of the alloy is increased without" causing a decrease in its strength.

A further object of my invention is to provide an improved aluminum brass having an alpha beta or a beta structure in which manganese, or a mixture of manganese and iron, has been substituted for the zinc in such proportions that the strength of the alloy is increased without causing a decrease in its ductility.

Brass composed of 64 to 54% copper and from 46 to 36% zinc, crystallizes upon coolf ing in the alpha beta structure, while brass containing between 46 and 50% zinc and from 54 to 50% copper .crystallizes upon cooling in the beta structure.- I-t is a well known Yfact that the substitution of aluminum for part of the zinc in a brass having an alpha beta ora beta structure causesan increase in strength and a decrease in ductility. Such a substitution also reduces the amount of the alpha constituent in a brass having an alpha beta structure and if suiicient quantities are adde the alpha constituent can beentirely eliminated. This also has vthe tendency to reduce the ductility of the alloy because brass having an alpha beta structure is usually moreductile than brass having a beta structure. It will, therefore, be understood that the increase in strength that can be produced by the substitution of aluminum' for part pletely, determined by the ductility required. As a general rule, the aluminum content of the brass should not exceed 5%,

In order to further increase the strength of an aluminum brass, it has heretofore been proposed to substltute man anese and iron for part of the zinc, and al oys comprising .a beta structure is not always benecial because the addition of these ingredients in different roportions'causes widely divergent results. or example, when they are added in certain proportions they cause a decrease in both the strength and ductility of the alloy. Other pro ortions increase the strength of the alloy ut reduce the ductility, or, conversely, increase the ductility but reduce the strength.

I have made the discovery that when certain well dened proportions of iron and manganese are substituted for a. part of the zinc in an aluminum brass substantially free from all but accidental traces of tin and having an alpha beta or a beta structure, an alloy `will be produced that is improved both in ductility and strength. The proportions of iron and manganese may also be varled so that an increase i'n strength may be produced without affecting the ductility of the alloy, or an increase in ductility may be produced without aliecting the strength.

My invention will be better understood by relerlnce to the accompanying drawing' in w 1c Figure 1 is a graph showing the proportionsof iron and manganese which, when substituted for part of the zinc in an aluminum brass, increase the ductility Without decreasing the strength, and

Fig. 2 is a graph showing the proportions of the same ingredients which, when substituted for a portion of the zinc in a similar brass, increase the strength without reducing 'the ductility. of the zlnc in a brass is largely, if not com- Referring to Fig. 1 of the drawing, the ordinates indicate the percentage of iron and the abscissae the percentage of manganese to be substituted in the alloy. The dotted line 1 designates the increase in percentage elongation in two inches obtained in an aluminum brass having an alpha beta or a beta structure when iron and manganese have been substituted for a part of the zinc in the brass in the proportions designated by the heavy line 2. While the substitution of iron and manganese for part of the zinc in the alloy in the proportions indicated by the line 2 produces an alloy having increased ductility, the tensile strength of the alloy is not decreased.

The graph shows that an increase in ductility, as measured'by percentage elongation in two inches, may be obtained without loss of strength, when the proportion of iron in the alloy is varied between about 1.25% and 4.8% and the proportion of manganese between Oand 5%.

It will be noted that when about 1.6%

iron and about .7% of manganese are substielongation was 21% in two inches.

tuted for 2.3% of zinc in an aluminum brass, the ductility of the alloy as measured by percentage elongation in two inches will be approximately 11% greater than that of ordinary aluminum brass. For example, an aluminum brass composed of 58% copper, 2% aluminum and the balance zinc, was tested. The tensile strength ofthe alloy was 87 ,000# per square inch and the percentage Iron in the proportion of 1.6% and manganese in the proportion of 0.7% were then substituted for 2.3% of the zinc and the resulting alloy, consisting of: 58% copper, 2% aluminum, 1.6% iron, 0.7 manganese, balance'zinc, had a. tensile strength of 87 000# per square inch and a percentage elongation of 32% in two inches. p

Referring to Fig. 2 of the drawing, the ordinates and absclssae indicate the percentages of iron and manganese, respectively, the heavy line 3 the percentages of manganese and iron that may be substituted in an aluminum brass for a part ofk the zinc without causing a decrease in ductility, and the dotted line 4 the increase in tensile strength that is effected by this substitution. It will be noted from this graph that/ when iron and manganese are subs ituted for zinc in an alumik num brass having an alpha betal or a beta structure in a range of proportions between 0 and 2% iron, and between 2 and 7% manganese, an improved alloy willbe produced that has a greater-tensile strength than an ordinary aluminum brass, and is equally as ductile.

While the proportions of iron and manganese represented by any point on the heavy line 3 in Fig.'2 of the drawing may be utilized,

itis apparent that good results may be produced by substituting about 1% iron and about 3.65% of manganese for 4.65% of zinc in an aluminum brass having an alpha beta or a beta structure, and that the increase in tensile strength which is obtained by making a greater substitution is very limited. When iron and manganese in the proportions just specied were substituted for 4.65% zinc in an aluminum brass containing 58% copper, 2% aluminum and the balance zinc, an alloy was produced having the following composition: 58% copper, 2% aluminum, 1% iron, 3.65% manganese, balance zinc. This alloy had a tensile strength of 93,700# per square inch while the tenslle strength of the original alloy was only 87 ,000#. The ductility of the two alloys, as determined by the percentage of elongation; was practically the same.

Since the 1 proportions of iron and manganese that are effective in causing an increase in ductility without causing a decrease in strength range from 11/2 to 5% iron and from 0 to 5% manganese and the proportions of the same ingredients that cause an increase in strength without causing a loss 1n ductllity range from v0 to 2% iron and 2 to 7% manganese, it will be obvious that when the proportions of iron and manganese are maintained within the limits of 117/2 to 2% iron and 2 to 5% manganese, alloys having both an increased strength and ductility will be produced.

It will be recognized that in practice, it is diflicult to produce an alloy having the exact percentages represented by the heavy lines 2 and 3 in Figs. 1 and 2 and where specific proportions of the ingredients are mentioned in the claims, lit is Vcontemplated that there may be some variations in manufacture, such as an increase or decrease of about .25% of either or botlthe manganese and iron.

W'hi I have described a preferred embodiment of my invention and have illustrated by examples and graphs the proportions of iron and manganese, which when substituted for zinc in an aluminum brass having an alpha beta or a beta structure, produce an alloy having the desired characteristics, it wil be understood that various modiications may be made therein without departing from the spirit of my invention.

For example, the aluminum content may be varied fromrO to 5% and the iron and manxganese may be varied within those ranges that l will produce an alloy having increased strength and ductility, an increased ductility without a decrease in strength, or an increase in strength without loss in ductility. It will also be understood that varying. amounts of impurities may be present in the alloys.. It is essential however that the proportion of tin should be kept below a 4range of .5 to .75% because of its deleterious properties.

Other modifications of my invention will be apparent to those skilled in the art. I, therefore, desire that only such limitations shall be imposed thereon as are required by the PIOF mit and the appended claims.

I claim as my invention:

1. An alloy comprising zinc, copper, aluminum, iron and manganese that is substantially free from tin, the zinc, copper and aluminum being present in such proportions that the alloy Will crystallize in the alpha beta or beta structure, the proportion of iron u being less than 2% and the proportion of manganese being less than 2.5%.

2. An alloy comprising zinc, copper, aluminum, iron and manganese that is substantially free from tin, the zinc, copper and aluminum being present in such proportions that the alloy will crystall'ize in the alpha beta or minum being present in such proportions that the alloy Will crystallize in the alpha beta or beta structure, the proportion of iron being .fat least 1% but less than 2%, and the proportion of manganese being less than 2.5%.

4. An alloy comprising zinc, copper, aluminum, iron and manganese, the zinc, copper and aluminum being present in suchproportions that the alloy Will crystallize in the alpha beta or beta structure, the amount of iron being greater than .75% but less thanV 2%, the amount of aluminum being less than 5% and the amount of manganese ranging from .25% to 2%.

In testimony Whereof,.I have hereunto subscribed my name this 12th day of December, 1928.

OWEN W. ELLIS.

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