Processes for welding composite materials and articles therefrom

摘要

The invention is directed at a method for welding a composite material and to welded structures thus prepared. The method includes a step of contacting a substrate material with a composite material, wherein the composite material includes a pair of spaced apart steel sheets and a core layer between the sheets; the volume of the core layer is about 25 volume % or more, based on the total volume of the composite material; the core layer includes a plurality of steel fibers arranged in one or more masses of fibers that extend the thickness of the core layer so that the core layer is in electrical communication with the steel sheets; and the steel fibers have a cross sectional area perpendicular to the length of the fibers from about 1×10−5 mm2 to about 2.5×10−2 mm2.

主权项

1. A process of forming a weld joint comprising the steps of:
providing a substrate material, wherein the substrate material is a metallic material; providing a light weight composite material having a stamped configuration, a roll formed configuration, a bent configuration, or a punched configuration; forming a weld stack including at least the substrate material and the light weight composite material; and welding the light weight composite material directly to the substrate material; wherein the step of welding includes a step of applying a weld current to the substrate material and the light weight composite material using electrodes of a resistance welding apparatus to weld the substrate material with the light weight composite material; the step of welding includes a first weld stage having an upslope weld current starting at an initial weld current followed by an increase to the weld current; wherein the light weight composite material includes a pair of spaced apart steel sheets and a core layer including a filled polymeric material between the steel sheets, wherein the core layer has a thickness; the filled polymeric material is present at a concentration from about 30 volume % to about 75 volume %, based on the total volume of the light weight composite material; the core layer includes a polymeric matrix and a plurality of steel fibers arranged in one or more masses of fibers that extend the thickness of the core layer so that the core layer is in electrical communication with the steel sheets, the polymer matrix includes one or more polymers, and the polymer(s) and steel fibers are present at a volume ratio of polymer(s) to steel fiber of about 19:1 to about 2.2:1; the steel fibers have a length of about 200 μm or more and less than 7 mm; and the steel fibers have a generally rectangular cross-section perpendicular to the length of the fibers.