Reducing the Cost of Ingots Utilized in Large Steam Cycle Components by Heat Flux Manipulation during VAR Processing to Control Solidification

In its efforts to develop more efficient and cost-effective fossil fueled power generation, DOE has validated new alloy groups that are capable of withstanding the temperatures, pressures and extreme environments necessary to achieve the performance of these next generation fossil-based systems. Typically, these are nickel-based alloys that are both expensive to manufacture and prone to segregation during manufacturing. DOE specifically identifies the reduction of cost of these alloys as a key to making the next generation of fossil energy systems more affordable. Additionally, industry experts have explicitly identified the desire for larger Vacuum Arc Remelted (VAR) ingots as a major technical barrier yet to be overcome in order to enable advanced fossil generation technologies. This SBIR addresses these barriers by considering several key factors in the production cycle in order to provide advanced control over the melting process resulting in better yield and improved quality while requiring less energy to do so. By combining an advanced measurement system under development by Ampere Scientific, with the application of transverse magnetic forces we are capable of tailoring the solidification profile in the ingots allowing us to achieve an estimated 20% reduction in costs, including the reduction of waste material. In Phase I, the goal is to validate the applicability of our approach by a) investigating the system dynamics in an experimental VAR and validating the measurement technology against situations where these alloys are melted (short arc gap influenced by drip short dynamics); verifying that the low current profiles during the melting of these alloys aren’t prone to magnetic field interference from other sources; and c) development an arc gap measurement since the arc gap is so critical to the defect free melting of the alloys in question. In so doing, the following three tasks will be accomplished during the Phase I work: a) Modify existing research VAR to sustain the necessary validation experiments; b) Run a statistically relevant number of tests to validate the technology and to investigate scaling; and c)Analyze data to establish the relationship arc conditions and defect generation. Our technology has commercial application to all Vacuum Arc Remelting and Electro-slag Remelting facilities in the United States and throughout the world. In particular, the melting of almost all specialty metals and many highly alloyed steels are manufactured in these furnaces, which have not changed in more than 4 decades. In so doing we will electrical and yield loss commonplace in this industry. The beneficiary of this effort are the ingot producers and their customers, the consumer through the availability of electricity from advanced generation systems, and the DOE through the success of advanced fossil generation programs such as the AUSC. Additional beneficiaries include other energy related users of super alloys such as sCO2 components; and non-energy applications such as aircraft rotating parts where defects can cause catastrophic results.