Improved Vacuum Arc Remelting (VAR) Processing

Project Lead: Raytheon
Partners: Purdue University, Connecticut Center for Advanced Technology (CCAT)

Member % Cost Share: 50%
CESMII % Cost Share: 50%
Duration: 18 Months

Problem Statement

Dirty white spot (DWS) defects in forged IN718 turbine parts pose a significant safety risk to the aviation, marine, and power generation industries. Despite the manufacturing process being specifically designed to minimize these defects, engine failures still occur due to DWSs. IN718 turbine parts for turbine engines are produced using a triple melting process which requires substantial energy, time, and cost. Improving this process can have significant energy implications across multiple industries.

Project Goal

The goal of the proposed program is to develop a simulation/testing framework to determine the feasibility of using ultrasound to mitigate DWSs in the VAR process. If it can be shown that this method effectively reduces the frequency of DWSs, IN718 parts can be double melted as opposed to requiring triple melting.

Technical Approach

The proposed program entails 1) Multiscale solidification models to quantify the effect of ultrasound on crown formation; 2) Crown vibration, fracture, and melting models for ultrasonic feature optimization to mitigate risk of fall-in particles to DWS formation; 3) Specimen design, manufacturing, and experimental testing for model development, calibration, and validation.

Deliverables/Outcomes/SM Marketplace

  • Delivered multiscale VAR model to predict the effect of ultrasound on solidification.
  • Delivered physics-based multiscale model, validated with experimental testing data.
  • Delivered fall-in particle model and experimental data from ultrasonic fracture testing.
  • Integrated Computational Materials Engineering based predictive models to prevent dirty white spots through ultrasonic excitation are broadly applicable to the Vacuum Arc Remelting industry, for aerospace, marine, and other power generation applications.

Potential Impact

Eliminating the requirement for a third melting step for IN718 turbine parts used in aviation, marine, and energy generation applications will result in >30% energy savings over the current practice. 

    • Considering only turbofan engines, the total energy saved is ~264 GWh, equivalent to the annual energy consumption of >25,000 US homes
    • Including all turbine engines (power generation, turboprop, and marine), the total annual energy savings is ~600 GWh, equivalent to >57,000 US homes


The proposed program will contribute to advancing the CESMII goals and objectives through the following performance metrics:

  • Energy Productivity
  • Energy Efficiency
  • Industry Deployment Costs
  • Workforce

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