Backside shielding assembly for plasma arc welding

摘要

A backside shield assembly for use during plasma arc welding. Two elongated closed boxes are supported in a selected spaced apart distance suitable for positioning the boxes on opposite sides of the backside of a weld line. Each box includes an inlet tube for an inert gas that generates a first side of the box and communicates with an elongated tube running along the inner surface of the first side. Perforations are provided in the elongated tubes. The balance of the interior of each box contains a flow diffusing material. The second box side, opposite the first side, is perforated. In use, the assembly is placed inside a conventional welding chill bar channel with the boxes on opposite sides of a weld line. The second surface is spaced slightly from the panel to be welded. An inert gas is directed through the inlet tubes, elongated tube perforations, diffusing material and out through the second side perforations. Since the only opening thereafter is oriented toward the volume between the boxes, the gas enters and fills that volume, where the weld flame and cooling weld bead are located. The gas covers the weld bead and prevents contamination from air borne contaminants.