A method is disclosed for producing an energetic metastable nano-composite material. Under pre-selected milling conditions a mixture of powdered components are reactively milled. These components will spontaneously react at a known duration of the pre-selected milling conditions. The milling is stopped at a time at which the components have been compositionally homogenized to produce nanocomposite powder, but prior to said known duration, and thereby before the spontaneous reaction occurs. The milled powder is recovered as a highly reactive nanostructured composite for subsequent use by controllably initiating destabilization thereof.

Nano-composite energetic powders prepared by arrested reactive milling

A self-contained crucible assembly (50) for forming a weld between a pair of metal articles (190, 192), includes a container (52) with side walls (54) and a fusible bottom (56), a refractory material (60) lining the side walls (54), an exothermic weld material (64) within the container (52), an ignitor (66) partially within or close to the weld material (64) and partially external to the container (52), and a cover (74) sealing the weld material (64). The ignitor (66) may be stiffened to maintain its shape, and keep it in a desired position relative to the exothermic weld material (64). The crucible assembly (50) is configured to be placed on mold (178) having a chamber (176) therein. Upon ignition of the weld material (64) via actuation of the ignitor (66), the weld mateiral (64) reacts exothermically to produce molten weld metal and slag. The fusible bottom (56) of the container (52) is melted by the liquified molten metal, and the weld material (64) flows into a weld chamber (186) of the mold (178) to produce the weld.

Welding apparatus and method

Exothermic reaction mixtures are electrically ignited with a low cost foil strip of two conductive strips separated by a layer of insulation. One or more holes are formed in the ignitor to create shaped spark plasma on one side and a venting plasma on the opposite side of the hole. The spark with low energy requirements is sufficient to ignite exothermic reactions for welding, casting and other uses. The ignitor may be part of reusable crucibles and molds, or expendable packages, containers, and molds, or smaller squibs for igniting larger charges. The ignitor may be immersed in or substantially adjacent the charge of exothermic material. The spark forming hole or holes is made and shaped by a punch in a simple and low cost manner. The ignitor eliminates the need for starting powders or materials and flint gun ignitors.

Exothermic reactions and methods

A weld mold assembly Which includes a crucible section for exothermically reacting weld material to form a molten metal, a weld mold having a weld chamber with an opening for receiving the molten metal and a plurality of guide hales for receiving ground rods and wires, and a cylindrical or tapered conversion plug sealably inserted into at least one of the guide holes to provide a weld. assembly with a variety of different configurations.

Exothermic welding mold conversion plug

Exothermic welding apparatus includes a toggle frame jig for supporting vertically split molds. The toggle includes a post projecting parallel to the main pivot of the jig on which telescopes a crucible support. The crucible support includes a handle extending above the crucible when secured to the support. A quick acting toggle connects the support and post enabling the crucible to be assembled, cleaned, or prepared remote from the molds and then quickly installed and locked in position.

Exothermic welding apparatus

An improved thermite reaction containment vessel and method of using the same includes a crucible in which the exothermic material is contained and which is connected at its lower end via a tap hole to a weld chamber in which the parts to be welded are positioned. On top of the crucible is positioned a baffle assembly which includes a plurality of expansion chambers which allows the escaping gas to expand and be reduced in velocity. As the gases move from one expansion chamber to the next the gases change direction. The expansion, direction change and the large surface area of the baffle assembly allows the gases to slow and cool before being exhausted leaving behind molten metal spatter or flame and greatly reducing the amount of smoke exhausted since particulate matter is accumulated on the baffle interior surface. Several forms of baffle assembly are disclosed using inverted stacked metal cups. The baffle assembly may be used in conjucntion with a filter assembly and remote electrical ignition or without a filter assembly and conventional starting material, with such matrial being ignited through the top of the baffle assembly.

Exothermic welding apparatus including a baffle cover assembly

The invention provides a method and means of producing weld metal for use in joining two or more aluminum containing pieces. The method includes the steps of providing a novel mixture of reactants comprising silicon, a reducing agent, a metallic compound which is exothermically reduced by the reducing agent, and a filler metal that does not react with the metallic compound. The mixture of reactants is then exothermically reacted so as to form the weld metal for joining the metallic pieces. At least about 90 percent by weight of the weld metal is produced by the silicon and the filler metal and at least about 90 percent by weight of the weld metal has a chemical composition substantially similar to that of at least one of the metallic pieces being joined.

Aluminum welding process and mixture of reactants for use in such process

The invention provides a new and improved process and exothermic reaction mixture for use in the process for producing molten weld metal. The molten weld metal is used in joining one non-ferrous metal piece with at least one other metal piece. The process and exothermic reaction mixture have distinct advantages over the prior art. These advantages include a higher filler metal yield, reduction of odor, and a higher quality corrosion resistant weld. These advantages are accomplished by a process wherein a reactant mixture is provided which has a reducing agent, a filler metal which does not react with any of the compounds of the mixture, and two or more metallic compounds which are exothermically reduced by the reducing agent. The metallic compounds subsequently form a compound, with the reducing agent, having a high heat of formation which provides an exothermic reaction with sufficient heat to melt the filler metal. The reactant mixture is exothermically reacted to release heat and melt the filler metal and provide a flow of filler metal from the reactant and product mixture which may be contacted with objects to be welded by the filler metal.

James E. Whetsel

Papers

Exothermic welding apparatus including a baffle cover assembly

Aluminum welding process and mixture of reactants for use in such process

Welding process and mixture of reactants for use in such process.

Mixture of reactants for use in welding