Metal working – Method of mechanical manufacture – Process for making bearing or component thereof
Reexamination Certificate
2003-03-26
2004-03-30
Johnson, Stephen M. (Department: 3641)
Metal working
Method of mechanical manufacture
Process for making bearing or component thereof
C029S903000, C042S071020, C042S076020
Reexamination Certificate
active
06711819
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to firearms. More specifically, the present invention relates to firearms having components, such as frames and cylinders, made of scandium containing aluminum alloys, which alloys include alloying elements composed of 0.05% to 0.30% scandium and may include light weight alloying metals such as magnesium, chromium, copper and zinc, and additional rare earth elements such as zirconium, and to a method for heat treating the scandium containing aluminum alloy firearm components.
BACKGROUND OF THE INVENTION
Firearm frames composed of aluminum alloys have been known for some time. The life of such firearms is limited because conventional aluminum alloys breakdown relatively fast when compared to heavier materials such as steel. Furthermore, firearms composed of heavier materials are relatively heavy. Heavier firearms are inconvenient to carry concealed.
Revolver cylinders have not been manufactured using aluminum alloys because aluminum alloys of the prior art lack the strength and endurance to hold up under the stresses caused when the revolvers are discharged. Aluminum cylinders are subject to excessive wear and/or damage upon discharge of the revolvers making the cylinders inoperable. The damage sustained includes pitting and deformation of the cylinders under the high impact upon discharge of the revolver. Cylinders have been made of heavier materials such as steel and titanium alloys; however, revolvers having conventional steel cylinders are quite heavy, and titanium alloys are very expensive.
Firearms include many components in addition to a frame and a cylinder. Such components include, but are not limited to, barrel, slide, yoke, ejector, ejector rod, sear, hammer, and trigger. These parts are typically made of heavier metals which aggregate weight, including the frame and cylinder, if present, results in an overall heavier firearm than would result if lighter alloys were used in place of the heavier metals for as many parts as possible. Each component composed of heavy alloys, such as steel and titanium, increases the overall weight of the firearm in comparison to a firearm having lighter metal components. Components requiring high durability, endurance and strength have not been made of aluminum alloys. Many such components must function with minimum degradation under high impact and radical temperature change conditions. Such conditions occur repeatedly upon discharge of the firearm. Components of the firearm must be able to withstand the abuse inflicted thereupon, and prior art aluminum alloys have been unable to meet this requirement for a large number of firearm components.
Scandium is one of the most potent alloying elements in the periodic table. When added to an aluminum alloy, scandium significantly increases strength, and reduces grain size. Furthermore, scandium is a very light metal with a much higher melting point (2806.00° F.) than aluminum (1220.58° F.) making such alloys more durable in that they have longer life spans, have higher strength, and are degraded less by temperature extremes. In other words, aluminum-scandium alloys can sustain a larger range of repeated abuses including more extreme temperature variations than conventional aluminum alloys. Scandium containing aluminum alloys have improved strength, improved resistance to hot cracking, and improved resistance to recrystallization. Scandium provides the highest increment of strengthening per atomic percent of any alloying element when added to aluminum. Likewise, scandium containing aluminum alloys have dramatically greater thermal stability than aluminum alloys lacking scandium. Scandium containing aluminum alloys have been used in the manufacturing of baseball bats, bicycle frames, golf clubs, various exercise equipment and aerospace applications.
Scandium containing aluminum alloys and their products are well known in the art. Aluminum and aluminum alloys of varying binary, ternary and multicomponent types having from 0.01 to about 5.0 percent by weight of scandium, which may also contain copper, magnesium, zinc, manganese, beryllium, lithium, iron, silicon, nickel, chromium, titanium, vanadium, zirconium, boron, bismuth and lead, are described in U.S. Pat. No. 3,619,181, assigned to Aluminum Company of America. U.S. Pat. No. 4,261,767, assigned to Creusot-Loire of Paris, discloses an alloy resistant to high temperature oxidation which includes chromium, nickel, iron, aluminum and at least one rare earth metal. Similarly, U.S. Pat. No. 5,059,390, assigned to Aluminum Company of America, discloses a dual-phase magnesium-based alloy consisting essentially of lithium, aluminum, a rare earth metal (preferably scandium), zinc and manganese. U.S. Pat. No. 4,261,742, assigned to Johnson, Matthey & Co., Limited, describes platinum group metalcontaining superalloys which may include 0.01 wt % to 3 wt % scandium plus chromium, aluminum, titanium, one or more of the platinum group metals, and nickel. Furthermore, U.S. Pat. No. 4,689,090, also assigned to Aluminum Company of America, describes superplastic aluminum alloys containing scandium.
Products composed of scandium containing aluminum alloys are well known in the prior art as mentioned briefly hereinabove. U.S. Pat. No. 5,597,529, assigned to Ashurst Technology Corporation (Ireland) Limited, discloses aluminum-scandium alloys which may be used in welding applications and bicycle components. U.S. Pat. No. 5,620,652, also assigned to Ashurst Technology Corporation (Ireland) Limited, discloses aluminum alloys containing scandium with zirconium additions which may be used in recreational, athletic structures and components thereof, and in certain aerospace, ground transportation, marine structures and components thereof. Neither of these applications disclose the use of scandium containing aluminum alloy firearms. The recreational equipment disclosed are made from sheets of metal instead of being extrusion molded or pressed from metal bars.
U.S. Pat. No. 5,624,632, assigned to Aluminum Company of America, shows an aluminum alloy product for use as a damage tolerant product for aerospace applications, including fuselage skin stock, which alloy may include scandium. U.S. Pat. Nos. 5,055,257 and 4,874,440, also assigned to Aluminum Company of America, describe superplastic aluminum products and alloys containing scandium. U.S. Pat. No. 5,882,449, assigned to McDonnell Douglas Corporation, discloses a process for preparing aluminum-lithium-scandium rolled sheet products. These patents do not describe lightweight firearms composed of scandium containing aluminum alloys.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, a scandium containing aluminum alloy firearm solving the aforementioned problems is desired.
SUMMARY OF THE INVENTION
The present invention relates to firearms having components made of scandium containing aluminum alloys which are composed of an aluminum alloy containing alloying elements which include, in addition to aluminum, from about 0.05% to about 0.30% scandium plus light weight metals such as magnesium, chromium, copper, and zinc. The scandium containing aluminum alloy may also have zirconium as an alloying element, and may contain additional heavier metals and other rare earth metals. Preferably, the scandium containing aluminum alloy is composed of from about 0.05% to about 0.15% scandium, from about 7.5% to about 8.3% zinc, from about 1.6% to about 2.2% magnesium, from about 1.6% to about 2.0% copper, from about 0.02% to about 0.04% chromium, and from about 0.05% to about 0.15% zirconium with the balance being composed of aluminum. Incidental elements, impurities and other grain refiners may be present in the alloy as is well known in the art of metallurgy.
The scandium containing aluminum alloys used in the present invention have the following properties: yield strengths of 82 KSI to 100 KSI, tensile strengths of 88 KSI to 106 KSI, 12% to 19% elongation's, and 7% to 1
Fleury Kevin R.
Luty Jeffrey
Spencer Norman W.
Stall Thomas C.
Johnson Stephen M.
Smith & Wesson Corp.
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