US2109387A - Tin alloy - Google Patents

Description

UNQTED S? PAT TINY Daniel Hanson, Haselor, Thomas Poll-Walpole,

si ners to land No Drawing. 1 No. 89,998.

Application July Great Britain February 9,

Alcester, and William Tipton, England, as-

John Campbell, Kensington, Eng- 10, 1936, Serial 2 @laims. (Cl. 143-13) This invention relates to tin alloys and meth-- ods of producing the same.

It isknown that the metal tin, although ductile,

1c are largely used in making pewter and-for the tainers, the construction of chemically resistant 1.; plants and vessels, and the like.

however, have suficred from the disadvantage,

20 was temporary in character and disappeared in atmospheric temperatures.

The object of the present invention is to produce improved tin alloys having all the advantages of the known alloys but without the disadexceeding 130 C. but less than the temperature at which the alloy begins to melt, and cooling rapidly, as by quenching or cooling in air.

The invention also consists in a method according to the two preceding paragraphs in which the first heat treatment is followed by a further present without serious detriment.

The alloy thus produced is subjected to a heat treatment which consists in heating the alloy to a temperature exceeding 130 C. but less than the temperature at which the-all y be ins-11 to which it is heated for a period sufl lciently long to enable equilibrium to be attained at that temperaturc, a period .of half an hour to three hours being usually sufficient. The necesmry time Patent is: r 1. A method of producing a tin-alloy which ture exceeding. 130

cooling rapidly. as

can, however, be determined by miscroscopical examination of the structure.

The above treatment is preferably followed by a further heat treatment consisting in heating the alloy to a temperature not greater than 130 C. as, for example, by immersion in boiling water, and it is found that this second heat treat ment although not essential confers greater stability on the heat-treated alloy.

The period of second heat treatment-varies history of the metal, for example the size of casting, temperature of casting and whether the metal has been worked by rolling, etc.

Cadmium tin alloys produced by this invention show a considerable improvement in strength as compared with the tin itself or with cadmium tin alloys that have not been heat-treated without losing their ductility and this improvement in strength is retained either permanently or for a very long period of time at atmospheric temperatures.

Moreover, the alloys also possess the property of being strengthened by the. application, after heat treatment, .of working such as is involved in bending, pressing, forming, spinning and similar manufacturing processes, the improvement in strength thus acquired being wholly or partially retained either permanently or for very long periods of time. I

The alloys so produced are capable of being .used as an improved form of pewter and for making into sheet, strip, foil or other worked forms, or into articles made from such worked forms, and the percentage or cadmium employed, the temperature to which the alloy-is heated and the period of time for which such heating is maintained, as also therapidity of the cooling operation may be varied depending upon the purpose for which the alloy is to be used or any practical requirements that may have to be fulfllled.-

Having now described our invention, what we claim as new on desire to secure by Letters consists in adding to the tin an amount of codmium in excess of 1 per cent. and not exceeding 15 per cent. and heating the alloy to a tempera- C. but less than the temperature atwhich the alloy begins to melt, and by quenching or cooling in 1 2'. A method according to claim 1 in which the first heat treatment is-i'ollowed by a further heat treatmenticonsisting in heating the alloy to a temperature not greater than 130 C. as, for example, by immersion in boiling water.

L'DANIEL HANSON. l

THOMAS PEIL-WAIPOLE.

azncderate degree of cold