US1791148A - Lead alloy - Google Patents

Description

Patented Feb. 3, 1931 UNITED [STATES PATENT OFFICE ROBERT JAY SHOEMAKER, OF CHICAGO, ILLINOIS, ASSIGNOR TO S. 8: T. METAL COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS LEAD ALLOY No Drawing.

The invention relates to metal .compositions and its object is to provide a composition suitable for cable coverings, pipes and other articles, consisting principally of lead but containing very small quantities of lithium and small amounts of other metals, whereby the tendency of the lead to crystallize is largely overcome, and the lead is made tougher, and to a certain extent harder, by the use of a hardening agent or agents which will not corrode in moist atmospheres or dross out when the alloy is melted in casting for example.

Lithium used in relatively large quantities has been proposed as a hardening agent for lead. The disadvantage, however, of lead so hardened is that it is particularly liable to corrosion and to drossing when melted due to the large amount of the hardening agent present. The cost of such lead alloy is also very high since lithium is an expensive substance.

I have discovered that lead may be toughened, and hardened to some extent, and its tendency to crystallize very considerably reduced by the use of extremely small amounts of lithium, the effect of this alloying substance in producing a toughening effect on the lead being quite surprising and out'of all proportion to the amounts used; and that the cost of the alloy may be reduced without detriment to its qualities 'by using also as a hardening and toughening agent a certam amount of calcium and tin, in which case it appears to be necessary to introduce into the composition a very small quantity of aluminum to prevent the calcium from drosslng out.

The alloy sition:

Lithium 0.01% amount 0.02%.

Calcium 0.1% to 0.3%; preferable amount may have the following compoto 0.03% preferable Application filed August 2, 1928. Serial No.

Tin 0.25% to 0.5%; preferable amount 0.

O. Aluminum 0.02% to 0.1%; preferable amount 0.5%.

Lead to make up 100%.

It will be understood that the above proportions are by weight.

The aluminum appears to have no function so far as the hardening or toughening of the lead is concerned. Its value is in keeping the calcium from drossing out when the components are melted incompounding or When the alloy itself is melted,

The compound is made as follows The lead is first melted to a temperature of approximately 1600 Fahrenheit under a protective coating consisting preferably of molten calcium chloride. The tin and aluminum are introduced into the melt through the calcium chloride coating, either as metallic elements or, preferably for convenience, as tin-aluminum alloy. The calcium is then introduced in the same Way, it being desirable to introduce the calcium after the tin and aluminum in order to prevent the calcium chloride from foaming. The melt is then allowed to cool to a temperature of about 600 to 700 Fahrenheit, the calcium chloride being in the meantime stripped ofi' after it solidifies, which takes place at a temperature of approximately 1000 Fahrenheit. Rosin is then introduced into the lead and the lithium mixed in While the rosin is burning.

he toughenss of the lead, and also its hardness in comparison with pure lead are quite remarkable in view of the very small quantities of alloying agents used. More; over the tendency of the lead to rystallize is checked to a very large degree. The alloy is stable, provided cated are not exceeded, both as against corrosion in moist atmospheres and as against drossing when the metal is melted 1'. r casting, for example.

I claim:

1. A tough, slightly hardened, non-corrosible lead alloy consisting of lead and, by weight of the alloy, from 0.01% to 0.03%

5 lithium; from 0.1% to 0.3% calcium; from 0.25% to 0.5% tin; and from 0.02% to 0.1% aluminum.

2. A tough, slightly hardened, non-corrosiblc lead alloy consisting of lead, and by 'weight, approximately 0.02% of lithium; 0.2% calcium; 0.3% tin; and 0.05% aluminum ROBERT JAY SHOEMAKER.

I claim:

1. A tough, slightly hardened, non-corrosible lead alloy consisting of lead and, by weight of the alloy, from 0.01% to 0.03%

5 lithium; from 0.1% to 0.3% calcium; from 0.25% to 0.5% tin; and from 0.02% to 0.1% aluminum.

2. A tough, slightly hardened, non-corrosilole lead alloy consisting of lead, and by weight, approximately 0.02% of lithium;

w 0.2% calcium; 0.3% tin; and 0.05% aluminum ROBERT JAY SHOEMAKER.

CERTIFICATE OF CORRECTION.

Patent No. 1,791,148. Granted February 3, 1931, to

ROBERT JAY SHOEM AKER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 49, for the decimal character "0.5%" read 0.05%; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of February, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,791,148. Granted February 3, 1931 ROBERT JAY SHOEMAKER.

printed specification of the above numbered patent Page 1, line 49, for the decimal character "0.5%" read 0.05%; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of February, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.