US3870513A - White metal casting alloy and method of making same - Google Patents
White metal casting alloy and method of making same Download PDFInfo
- Publication number
- US3870513A US3870513A US420948A US42094873A US3870513A US 3870513 A US3870513 A US 3870513A US 420948 A US420948 A US 420948A US 42094873 A US42094873 A US 42094873A US 3870513 A US3870513 A US 3870513A
- Authority
- US
- United States
- Prior art keywords
- alloy
- tin
- antimony
- white metal
- lead
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 50
- 239000000956 alloy Substances 0.000 title claims abstract description 50
- 229910001361 White metal Inorganic materials 0.000 title claims abstract description 11
- 239000010969 white metal Substances 0.000 title claims abstract description 11
- 238000005058 metal casting Methods 0.000 title abstract description 6
- 238000004519 manufacturing process Methods 0.000 title abstract description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910052718 tin Inorganic materials 0.000 claims abstract description 24
- 229910052787 antimony Inorganic materials 0.000 claims abstract description 20
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 14
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000000203 mixture Substances 0.000 abstract description 13
- 238000001816 cooling Methods 0.000 abstract description 2
- 239000004615 ingredient Substances 0.000 abstract description 2
- 238000005266 casting Methods 0.000 description 7
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 6
- 239000010931 gold Substances 0.000 description 6
- 229910052737 gold Inorganic materials 0.000 description 6
- 238000007654 immersion Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000013522 chelant Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 241000220010 Rhode Species 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000006023 eutectic alloy Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C13/00—Alloys based on tin
Definitions
- Alloys of this type embodying a high tin composition are known in the trade as white metal alloys, and such alloys must generally meet the following requirements.
- the cast alloy must lend itself to a high degree of polishing.
- the cast alloy must i be capable of being effectively and efficiently plated.
- the cast alloy must not be excessively brittle, since the cast articles, particularly where designed for jewelry use, frequently embody prongs that must be bendable.
- the casting alloy must have good flowability.
- White metal alloys by definition, comprise a high tin content, generally upwards of 90% by weight. It is quite conventional to alloy antimony with tin, since the antimony adds a desired degree of hardness to the alloy, without unduly or adversely affecting the castability of the tin.
- one of the more conventional prior art alloys of this type is a product of American Smelting & Refining Co. and is called OR-8 and comprises 92% tin and 8% antimony.
- Other prior art alloys. in addition to tin and antimony may also comprise lead in order to increase the flowabilityof the alloy, or copper, in order to increase the strength of the alloy.
- compositions comprising 94.5 parts tin, one part antimony, and 4.5 parts lead; or 92 parts tin, 4 parts antimony, and 4 parts lead; or 90.5 parts tin, 7.5 parts antimony, and 2 parts copper.
- the alloy of the present invention may be cast at a temperature of 500 550 F.
- This lower casting temperature is a pronounced advantage, since it promotes longer mold life, particularly where the molds are of rubber construction.
- the alloy of the present invention has all of the other necessary characteristics of a good casting alloy, i.e., readily lends itself to high polishing, is capable of being effectively plated, and has good flowability.
- the present composition appears to be more effective in these respects than the conventional prior art white metal casting alloys.
- an alloy comprising 90.5 92.5% tin, 2.9 3.1% antimony, 1.4 l.6% cadmium, and 3.3 3.771 lead achieves the advantageous results hereinbefore discussed.
- the alloy comprises 92% tin, 3% antimony, 1.5% cadmium, and 3.5% lead. It is important to note that since cadmium adds toxicity to the alloy, an excessive amount (over 5%) would be detrimental.
- the presence of the cadmium is not only not detrimental, but appears to be highly desirable in that it adds to the ductility of the alloy and at the same time lowers the casting temperature thereof.
- the alloy of the present invention has a unique crystalline structure of its own, which can be described as true crystalline, in comparison with the amorphous structures of OR-8, which indicate a two-phase eutectic alloy. This is thought to be attributable to the presence of cadmium in the composition.
- the lead and antimony are mixed with ofthe tin to be used at a temperature of approximately 800 F. until the antimony dissolves, at which point the other 25% of the tin is added to the mixture and is homogeneously dispersed therein, as by conventional mixing apparatus. After the mixture has become homogenous, it is allowed to cool until it reaches a temperature of 475 F. or slightly lower, at which point the cadmium is added and mixed therein until dissolved.
- the alloy is now ready for easting and, as previously stated, may be cast and formed at temperatures of 500 550 F.
- the tin should be 99.89l% pure, while the cadmium should be 99.99% pure and the lead 99.9% pure in order to obtain the most desirable results.
- the system used was a gold plating solution known commercially as Tivaklad GI-3 sold by Tivian Laboratories, Inc., of Buffalo, Rhode Island. It consists of a buffered gold chelate having the following composition:
- the capability of the present alloy to be gold plated by immersion is a completely unexpected result and constitutes a further advantage of the present alloy, since gold plating by immersion has not heretofore been possible with conventional prior white metal casting alloys.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Adornments (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Contacts (AREA)
Abstract
A white metal casting alloy comprising as its essential ingredients tin, antimony, cadmium and lead in specified proportions. The invention further comprises a method of making said alloy comprising the steps of mixing a certain amount of the tin to be used with the lead and the antimony at a temperature of approximately 800* F. until the antimony is dissolved and then adding the remaining amount of the tin and mixing until the alloy becomes homogenous, and then cooling the mixture to approximately 475* F., at which point the cadmium is mixed and dissolved.
Description
United States Patent 1 Darnell et a1.
1 1 WHITE METAL CASTING ALLOY AND METHOD OF MAKING SAME [75] Inventors: Robert S. Darnell, Washington, R.1.; Everett G. Morrissey, Bristol, Mass.
[73] Assignee: A. .1. Oster, C0., Providence, RI.
[22] Filed: Dec. 3, 1973 [21] Appl. No.1 420,948
[52] US. Cl 75/175 A [51] Int. Cl. C22c 13/00 [58] Field of Search 75/175 A, 175 R [56] References Cited UNITED STATES PATENTS 2,097,727 11/1937 Hanson et a1 75/175 A 2,180,139 11/1939 Dcitz 75/93 2,303,193 11/1942 Bouton et a1. 75/166 2,891,511 6/1959 Fehling 120/424 [451 Mar. 11, 1975 3,563,732 2/1971 Morisaki 75/175 A Primary Examiner-L Dewayne Rutledge Assistant ExaminerE. L. Weise Attorney, Agent, or Firm-Salter & Michaelson [57] ABSTRACT 3 Claims, No Drawings WHITE METAL CASTING ALLOY AND METHOD OF MAKING SAME BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to casting alloys of the type frequently used with centrifugal rubber molds, such as during the casting ofjewelry and similar products. Alloys of this type embodying a high tin composition are known in the trade as white metal alloys, and such alloys must generally meet the following requirements. First of all, the cast alloy must lend itself to a high degree of polishing. Secondly, the cast alloy must i be capable of being effectively and efficiently plated. The cast alloy must not be excessively brittle, since the cast articles, particularly where designed for jewelry use, frequently embody prongs that must be bendable. In addition, it is desirable that the alloy be capable of being cast at as low a temperature as possible, since the lower the casting temperature, the longer the life of the molds, particularly where of rubber construction. In addition, the casting alloy must have good flowability.
White metal alloys, by definition, comprise a high tin content, generally upwards of 90% by weight. It is quite conventional to alloy antimony with tin, since the antimony adds a desired degree of hardness to the alloy, without unduly or adversely affecting the castability of the tin. For example, one of the more conventional prior art alloys of this type is a product of American Smelting & Refining Co. and is called OR-8 and comprises 92% tin and 8% antimony. Other prior art alloys. in addition to tin and antimony, may also comprise lead in order to increase the flowabilityof the alloy, or copper, in order to increase the strength of the alloy. Examples of such prior art compositions are alloys comprising 94.5 parts tin, one part antimony, and 4.5 parts lead; or 92 parts tin, 4 parts antimony, and 4 parts lead; or 90.5 parts tin, 7.5 parts antimony, and 2 parts copper.
Although prior art alloys of the type above mentioned have proven to be generally satisfactory for their intended purposes, it has nevertheless been found that an alloy comprising as its essential ingredients tin, antimony, cadmium and lead, in proportions hereinafter to be specified, produces unexpectedly good results. As previously stated, the tin in the composition permits the alloy to be cast, while the antimony adds desired hardness thereto. The presence of lead increases the flowability of the alloy and helps to prevent undesirable shrinking of the cast alloy during cooling. The presence ofcadmium appears to make the alloy more ductile and bendable and at the same time lowers the temperature at which the alloy may be cast. More specifically, conventional prior art white metal alloys will normally be cast at a temperature of 650- 700 F. The alloy of the present invention, on the other hand, may be cast at a temperature of 500 550 F. This lower casting temperature is a pronounced advantage, since it promotes longer mold life, particularly where the molds are of rubber construction. In addition to the advantages just stated, the alloy of the present invention has all of the other necessary characteristics of a good casting alloy, i.e., readily lends itself to high polishing, is capable of being effectively plated, and has good flowability. In fact, the present composition appears to be more effective in these respects than the conventional prior art white metal casting alloys.
DESCRIPTION OF THE INVENTION In carrying out the present invention, it has been found that an alloy comprising 90.5 92.5% tin, 2.9 3.1% antimony, 1.4 l.6% cadmium, and 3.3 3.771 lead achieves the advantageous results hereinbefore discussed. Preferably, the alloy comprises 92% tin, 3% antimony, 1.5% cadmium, and 3.5% lead. It is important to note that since cadmium adds toxicity to the alloy, an excessive amount (over 5%) would be detrimental. In lesser amounts, however, i.e., approximately l.5% of the alloy, the presence of the cadmium is not only not detrimental, but appears to be highly desirable in that it adds to the ductility of the alloy and at the same time lowers the casting temperature thereof. In addition, it has been found by chemical analysis that the alloy of the present invention has a unique crystalline structure of its own, which can be described as true crystalline, in comparison with the amorphous structures of OR-8, which indicate a two-phase eutectic alloy. This is thought to be attributable to the presence of cadmium in the composition.
In making the present composition, the lead and antimony are mixed with ofthe tin to be used at a temperature of approximately 800 F. until the antimony dissolves, at which point the other 25% of the tin is added to the mixture and is homogeneously dispersed therein, as by conventional mixing apparatus. After the mixture has become homogenous, it is allowed to cool until it reaches a temperature of 475 F. or slightly lower, at which point the cadmium is added and mixed therein until dissolved. The alloy is now ready for easting and, as previously stated, may be cast and formed at temperatures of 500 550 F.
Also of importance is the purity of the metals used. Thus, the tin should be 99.89l% pure, while the cadmium should be 99.99% pure and the lead 99.9% pure in order to obtain the most desirable results.
In addition to the hereinbefore discussed advantages of the present alloy, it has additionally been found that it is possible to plate gold by immersion onto the alloy. More specifically, the system used was a gold plating solution known commercially as Tivaklad GI-3 sold by Tivian Laboratories, Inc., of Providence, Rhode Island. It consists of a buffered gold chelate having the following composition:
Gold 1 troy ounce Chelate 2 pounds Water 1 gallon pH 3.0 Temperature l40-l50 F.
The capability of the present alloy to be gold plated by immersion is a completely unexpected result and constitutes a further advantage of the present alloy, since gold plating by immersion has not heretofore been possible with conventional prior white metal casting alloys.
As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims or that 3. The method of making the alloy of claim 1, comprising the steps of mixing together at approximately 800 F. the lead, the antimony and approximately of the tin until the antimony has dissolved. then adding the remainder of the tin to the mixture and mixing same until the mixture has become substantially homogenous, then causing the mixture to cool to 475 F. or slightly less, then adding the cadmium and mixing until the latter has dissolved.
Claims (3)
1. A WHITE METAL ALLOY CONSISTING OF 91.5 - 92.5% TIN, 2.9 3.1% ANTIMONY, 1.4 - 1.6% CADMIUM, AND 3.3 - 3.7% LEAD.
1. A white metal alloy consisting of 91.5 - 92.5% tin, 2.9 -3.1% antimony, 1.4 - 1.6% cadmium, and 3.3 - 3.7% lead.
2. The alloy of claim 1 further characterized in that said tin is at least 99.891% pure, said cadmium is at least 99.99% pure, and said lead is at least 99.9% pure.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US420948A US3870513A (en) | 1973-12-03 | 1973-12-03 | White metal casting alloy and method of making same |
| GB4877574A GB1428070A (en) | 1973-12-03 | 1974-11-11 | White metal casting alloy and method of making same |
| DE19742455613 DE2455613A1 (en) | 1973-12-03 | 1974-11-23 | TIN ALLOY FOR THE CASTING OF JEWELRY AND SIMILAR ITEMS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US420948A US3870513A (en) | 1973-12-03 | 1973-12-03 | White metal casting alloy and method of making same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3870513A true US3870513A (en) | 1975-03-11 |
Family
ID=23668522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US420948A Expired - Lifetime US3870513A (en) | 1973-12-03 | 1973-12-03 | White metal casting alloy and method of making same |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3870513A (en) |
| DE (1) | DE2455613A1 (en) |
| GB (1) | GB1428070A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6197253B1 (en) | 1998-12-21 | 2001-03-06 | Allen Broomfield | Lead-free and cadmium-free white metal casting alloy |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2097727A (en) * | 1935-12-23 | 1937-11-02 | John Campbell | Tin alloys |
| US2180139A (en) * | 1937-08-14 | 1939-11-14 | Nassau Smelting & Refining Com | Purification of metals |
| US2303193A (en) * | 1941-10-04 | 1942-11-24 | Bell Telephone Labor Inc | Alloy |
| US2891511A (en) * | 1953-08-13 | 1959-06-23 | D C B Ltd | Writing instrument of the ball tip type |
| US3563732A (en) * | 1968-02-09 | 1971-02-16 | Daido Metal Co Ltd | Bearing alloys of tin based white metal |
-
1973
- 1973-12-03 US US420948A patent/US3870513A/en not_active Expired - Lifetime
-
1974
- 1974-11-11 GB GB4877574A patent/GB1428070A/en not_active Expired
- 1974-11-23 DE DE19742455613 patent/DE2455613A1/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2097727A (en) * | 1935-12-23 | 1937-11-02 | John Campbell | Tin alloys |
| US2180139A (en) * | 1937-08-14 | 1939-11-14 | Nassau Smelting & Refining Com | Purification of metals |
| US2303193A (en) * | 1941-10-04 | 1942-11-24 | Bell Telephone Labor Inc | Alloy |
| US2891511A (en) * | 1953-08-13 | 1959-06-23 | D C B Ltd | Writing instrument of the ball tip type |
| US3563732A (en) * | 1968-02-09 | 1971-02-16 | Daido Metal Co Ltd | Bearing alloys of tin based white metal |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6197253B1 (en) | 1998-12-21 | 2001-03-06 | Allen Broomfield | Lead-free and cadmium-free white metal casting alloy |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1428070A (en) | 1976-03-17 |
| DE2455613A1 (en) | 1975-06-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: FRY S METALS, INC., NEW JERSEY Free format text: NUNC PRO TUNC ASSIGNMENT;ASSIGNOR:A.J. OSTER COMPANY;REEL/FRAME:005916/0213 Effective date: 19911029 |