US1815528A - Lead alloy - Google Patents

Description

Patented July 21, 1931 UNITED STATES PATENT orrica ROBERT JAY SHOEMAKER, OF CHICAGO, ILLINOIS, ASSIGNOR T0 S. 80 T. METAL COM- PANY, OF CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS LEAD ALLOY No Drawing.

This invention relates to lead alloys and its primary object is to provide an alloy of lead having certain characteristics that make it particularly suitable for the manufacture of pipes, cable coverings, battery plates, linings for acid tanks, and for other like purposes. These characteristicsromprise a degree of hardness greater than that of pure lead but not enough to prevent the working of the metal when in a solid state and in some cases by cold processes; a very considerable increase in the tensile strength of the alloy in comparison with lead; a relatively high resistance to the corrosive or solvent effect of acid, in comparison with the usual hardened lead, compounds; and substantial non-corrosibility in the presence of water and moist air.

Another ObJGCt of the invention is to provide a lead alloy of the general character above indicated, from which the alloying metals will not dross out, or oxidize, in case the alloyis re-melted in fabricating cast articles, for example.

The compound consists principally of lead. The alloying metals are used only in relatively small quantities. The substance which may be termed the primary hardener is cal cium. In addition to the primary hardener a secondary hardener, cadmium, is used, and also, preferably, a small quantity of aluminum. The purpose of the aluminum is to prevent the drossing out of the calcium if the alloy is re-melted when exposed to the air. Inasmuch as it might be possible, though inconvenient, to protect the remelted alloy against oxidation, in which case the antidrossing function of the aluminum could be dispensed with, this ingredient cannot be considered absolutely essential although its use is to be preferred.

This alloy is composed of the following substances in the proportions, by weight, substantially as follows:

E wampZe 1.Calcium 0.05% to 0.4%. Preferred amount 0.2%. Cadmium 0.5% to 2.0%. Preferred amount 1.0% Aluminum 0.02% to 0.1%.- Preferred amount 0.05%. Lead to make up 100%. I,

The compound may also contaln mercury, as a secondary hardener, in which case the and on the contra Application filed December 2, 1929. Serial No. 411,217.

amounts of the ingredients will besubstantially as follows:

Ewample 2.--Calcium 0.05% to 0.4%. Preferred amount 0.2%. Cadmium 0.5% to 2.0%. Preferred amount 1.0%. Mercury 0.1% to 1.0%. Preferred amount 0.25%. Aluminum 0.02% to 0.1%. Preferred amount 0.05%.

Pipes made of the alloys given in the above two examples, employing the ingredients in the preferred proportions, will withstand bursting pressures substantially double those which ordinary lead pipe of corresponding Weightwill Withstand. A pipe made of this alloy is cheaper, heavier,-more durable and quore flexible than a copper or brass pipe of the same diameter. The alloy has a hardness of approximately 5 Brinell, about twice the hardness of lead. The hardness may be varied by increasing or decreasing the primary and secondary hardening agents within the limits above indicated. Like degrees of hardness to that indicated may be obtained by decreasing the calcium content and increasing the amount of tin or mercury, or both; or similarly, by increasing the calcium content and decreasing the amount of the secondary hardener or hardeners. The alloy will in any case gradually become harder as it ages during a period of several weeks or months and may reach a hardness of 16 Brinell.

In Example 2 the mercury content is kept low largely for economical reasons. The same effect could be obtained by using a larger amount of mercury and a smaller amount of the other hardening agents, but at a much higher cost.

It may be said that the cadmium can be used in considerably larger quantities than that indicated, but any substantial excess over 2% seems to have no hardening effect seems to make the alloy somewhat softer. owever, in fixing the upper limit of the cadmium at 2% I do not wish to be understood as precluding the use of a larger quantity although for the reasons stated, there would be no advantage, but on the contrary a disadvantage in such procedure.

The aluminum is used as an anti-drossing agent, as stated, to prevent oxidation of the calcium when the alloy is re-melted while exposed to the air. Its use in amount in excess of the upper limit specified above has no advantage and tends to makethe alloy mushy. Since the alloy may be re-melted under conditions to prevent oxidation of the calcium or may be used without re-melting, the aluminum cannot be regarded as essential, although its use is preferable.

When the alloy is used for making pi es the pipes can be formed by extrusion, a ter re-melting and solidification; although higher pressures are required than are commonly used in making ordinary lead pipe;

The alloy is preferably made as follows: The lead is melted and heated to a temperature of approximately 1500 F. under a covering of calcium chloride or other suitable flux. Aluminum is introduced into the lead through the flux. If desired one may use a alloy of aluminum and tin. Since the amount of the aluminum is small, the tin introduced in this way is so small in quantity as to be practically negligible. The calcium, as metallic calcium, is then introduced into the lead. The melt is allowed to cool to a temperature just above the melting point of lead, say to 700 Fahrenheit, and the calcium chloride covering which solidifies at about 1400 Fahrenheit is skimmed off. Or the batch can be allowed to solidify and is then re-melted to about 700 Fahrenheit. VVhichever procedure is followed, the mercury and cadmium are added when the melt is at about 700 F.

If desired the alloy may be compounded in part by an electrolytic process. The lead is melted and aluminum added. The melt is covered wizh calcium chloride and subjected to an electric current, the positive electrode being immersed in the calcium chloride and the negative electrode in the lead. The calcium chloride is split up, the calcium flowing into the lead and the chlorine escaping. The other ingredients are then mixed into the batch after the latter has been cooled to approximately 700 Fahrenheit, as in the other process.

In using the term consisting essentially in the claims, I do not mean to exclude the possibility of additional ingredients of such character or in such small amounts as not to substantiallyafi'ect the character of the alloy as described above.

This application is a continuation in part of my copending application, Serial No. 322,573, filed November 28, 1928 for lead alloy.

I claim:

1. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.05% to 0.4% and cadmium 0.5% to 2.0%.

2. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.2% and cadmium 1.0%.

3. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.05% to 0.4%; cadmium 0.5% to 2.0% and containing also mercury 0.1% to 1.0%.

4. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.05% to 0.41%; cadmium 0.5% to 2.0% and containing also mercury 0.1% to 1.0%; and aluminum 0.02% to 0.1%.

5. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by. weight substantially as follows: calcium 0.05% to 0.4%; cadmium 0.5% to 2.0% and containing also aluminum 0.02% to 0.1%.

6. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.2%; cadmium 1.0% and containing also aluminum 0.02% to 0.1%.

7. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.2%; cadmium 1.0% and containing also aluminum 0.05%.

8. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.2%; cadmium 1.0% and containing also mercury 0.1%. i

9. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.2%; cadmium 1.0% and containing also mercury 0.1% and aluminum 0.02% to 0.1%.

10. A slightly hardened, tough, non-corrosible lead alloy consisting essentially of lead and the following substances in amounts by weight substantially as follows: calcium 0.2%; cadmium 1.0% and containing also mercury 0.1% and aluminum 0.05%.

ROBERT JAY SHOEMAKER.