SBIR Phase I: Vacuum Arc Control using Arc Position Sensing and Induced Magnetic Fields

Kw Associates Llc, Albany OR

Investigators

Abstract

This Small Business Innovation Research Phase I project will provide the first technical advancement in the specialty metals industry (manufacturers of titanium and nickel) in more than 4 decades. Specialty metals are ubiquitous in our lives, with applications from aircraft parts to medical implants, yet the vacuum arc remelting (VAR) process, the work horse for this industry, has remained relatively unchanged since its development in the 1940?s. By coupling the ability to measure the location of electric arcs used for melting these high value alloys in the VAR, with the ability to steer the arcs, substantial electrical savings can be achieved, decreasing costs to the consumer and increasing reliability of the final products. For example, it is well known that the lack of understanding of the dynamics of the process leads to an estimated 8% yield loss, costing the US industry $1.024B per year in lost revenue through yield loss and electrical inefficiency, contributing to the high price of these products. This project proposes to decrease this loss by 50% by developing an applied feedback control technology capable of optimizing the energy distribution within these systems, providing better quality metals at a cheaper production price. The intellectual merit of this project is to prove that real-time control can improve plasma-based industrial processing systems. The innovation uses externally applied magnetic fields to manipulate arc position modes during melting operations. By coupling arc position sensing, which measures magnetic field vectors exterior to the process to determine arc positions interior to it, with active manipulation of externally derived fields, arcs can be precisely controlled. Relying upon years of development and validation of arc position sensing, coupled with Finite Element Analysis simulations and experimental validation, this technology will become the first active control of arc melting systems. The significant realization is that spatial and temporal control of the diffuse current paths can be controlled precisely if the validated measurement system of current location is coupled with external field generators. This effort will focus on the application to VAR furnaces but may have significant application to other processes with diffuse current pathways such as Joule heated systems, fuel cells, additive manufacturing or industrial microwave processing. The expected impact of arc control during melting is a reduction in manufacturing defects, an enablement of the production of ingots with increasing diameter, a reduction in energy required in alloy production, and improved safety of operations.