Yes...and no. A plasma cutter is a tool for the job, and there are a number of inexpensive options on the market. The limiting factor, in any case, is the thickness of this flat sheet metal. If it is relatively thin, then yes. You could use a flux welder (such as a stick-electrode) and basically burn through the plate by using a high-power setting. Think of this as using too-much power for a correct welding application. If I am not mistaken, there are welding rods produced for this type of application. Regardless, these edges will be jagged and you will lose more material in the cut than you would with a saw blade or grinder cut. Additionally, you will have to grind the edges to get the look of a professional edge. Try a scrap piece first and adjust as needed. Thanks for the question, and don't forget to be safe in all cutting and welding procedures.