Exothermic welding composition

Claim 2

A STOICHIOMETRICALLY BALANCED, HOMOGENEOUSLY DMIXED EXOTHERMIC WELDING COMPOSITION COMPRISING THE INGREDIENTS: FROM ABOUT 65 TO 85 WEIGHT PERCENT OF AN ADMIXTURE OF POWDERED ELEMENTAL ALUMINUM AND POWDERED IRON OXIDE WITH FROM ABOUT 9 TO 15 PERCENT OF SAID COMPOSITION BEING SAID POWDERED ELEMENTAL ALUMINUM, FROM ABOUT 5 TO 20 WEIGHT PERCENT OF POWDERED GLASS-FORMING SLAG MELTING POING DEPRESSANTS SELECTED FROM THE GROUP CONSISTING OF CALCIUM, SILICON AND MAGNESIUM MATERIALS WHICH DURING WELDING YIELD CALCIUM, SILICON AND/OR MAGNESIUM, AND AND AMOUNT OF SELECTED POWDERED ALLOYING AGENTS EFFECTIVE TO FORM A PREDETERMINED ALLOY, SAID COMPOSITION BEING COMPRESSED TO BETWEEN ABOUT 60 AND 80 PERCENT OF ITS THEORETICAL VOLUME WHEREBY THE QUANTITY OF ENTRAINED AIR IN SAID COMPOSITION IS MIMIZED.

Claim 3

An exothermic welding composition of claim 1 wherein the ingredients are selected from those inorganic reagents that do not evolve any substantial amounts of gases at the reaction temperature of said exothermic welding composition.

Claim 4

An exothermic welding composition of claim 1 including an amount of powdered calcium fluoride effective to reduce to a predetermined value the viscosity of a slag formed by the burning of said exothermic welding composition.

Claim 5

An exothermic welding composition of claim 1 including an amount of powdered oxidizing reagent effective to increase to a predetermined value the heat generated by the burning of said exothermic welding composition.

Claim 6

An exothermic welding composition of claim 1 wherein the powdered glass-forming slag melting point depressant includes calcium.

Claim 7

An exothermic welding composition of claim 1 wherein the powdered glass-forming slag melting point depressant includes silicon.

Claim 8

An exothermic welding composition of claim 1 wherein the powdered glass-forming slag melting point depressant includes magnesium.

Claim 9

An exothermic welding composition of claim 1 wherein the powdered glass-forming slag melting point depressant includes calcium silicide.

Claim 10

A stoichiometrically balanced, homogeneously admixed exothermic welding composition comprising the ingredients from about 65 to 85 weight percent of an admixture of powdered elemental aluminum and powdered iron oxide, from about 9 to 15 weight percent of said composition being powdered elemental aluminum, an amount of powdered glass-forming slag melting point depressant selected from the group consisting of calcium, silicon and magnesium materials which during welding yield calcium, silicon and/ or magensium sufficient to depress the melting point of the slag produced during the reaction of said exothermic welding composition to approximately the melting point of a metallic weld material produced by said reaction, the combined weight percentage of said powdered glass-forming slag melting point depressant varying from the weight percent of said powdered elemental aluminum by no more than about 5 weight percent, and an amount of powdered alloying agent effective to provide a predetermined weld alloy, said composition being compressed into an integral, structurally coherent weld element.

Claim 11

A stoichiometrically balanced, homogeneously admixed exothermic welding composition comprising the ingredients from about 65 to 85 weight percent of an admixture of powdered elemental aluminum and powdered iron oxide, from about 9 to 15 weight percent of said composition being powdered elemental aluminum, an amount of powdered glass-forming slag melting point depressant selected from the group consisting of calcium, silicon and magnesium materials which during welding yield calcium, silicon and/ or magensium sufficient to depress the melting point of the slag produced during the reaction of said exothermic welding composition to approximately the melting point of a metallic weld material produced by said reaction, the combined weight percentage of said powdered glass-forming slag melting point depressant varying from the weight percent of said powdered elemental aluminum by no more than about 5 weight percent, and an amount of powdered alloying agent effective to provide a predetermined weld alloy, said composition being compressed into an integral, structurally coherent weld element.