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The Mechanical Properties of Aluminum Weld Rods

Aluminum weld rods are made of solid aluminum alloys. Used in construction applications including irrigation pipes, banisters, loading ramps and truck beds, aluminum weld rods come in bulk packs, straight-cut lengths or wound around a reel. An aluminum alloy is classified according to its metal composition, which also determines its welding ability and mechanical properties.

  1. Aluminum Alloys

    • Aluminum alloys are defined as either cast or wrought alloys. Cast alloys are used for their rigidity and corrosion resistance, and are produced by either pressure die-casting, metal or sand molds. Alloying metals include zinc, iron, copper, manganese and nickel. Wrought alloys contain cast material that undergoes additional processing -- such as extrusion, forging, rolling or drawing -- which enhances the mechanical properties of the alloy.

    Welding

    • Aluminum alloy welding takes place via inert gas shielded processes using either argon or helium. However, welding is not straightforward; the aluminum oxide film must first be removed to prevent porosity. Porosity is also caused by hydrogen dissolving in liquid aluminum. Welding sometimes reduces some mechanical properties across the weld zone of the alloy. Casting alloys, particularly those containing copper, are generally not used because of their high porosity and susceptibility to cracking.

    Strength

    • The ductility and malleability of aluminum allows for the application of various manufacturing methods. While aluminum is light, its strength is improved upon alloying it with other metals followed by work hardening. In wrought alloys, work hardening accomplished by either heat treatment or cold working depending on the predominant alloying metal. Alloy strength is maintained at very low temperatures -- below -148 degrees F.

    Other Mechanical Properties

    • Aluminum alloy weld rods have a melting point of approximately 700 degrees C. They are insoluble in water and also non-flammable, so they pose no fire or explosion risk. Aluminum alloys are highly stable and unreactive, but produce metal oxide fumes during welding that may cause health concerns.

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