Heat Transfer and Calorimetry of Tubular Ni/WC Wires Deposited with GMAW

  • Author / Creator
    Scott, Kevin
  • A calorimeter for the deposition of metal during free-flight GMAW was developed for the purpose of measuring droplet heat content in Ni/WC tubular wires. By approximating the thermal gradients within the calorimeter to be second order polynomials the energy transferred to the calorimeter by the droplets was accounted for with more accuracy than previous investigations. Testing with 1.2 mm (0.045 in.) ER70S-6 steel wire agreed with previous studies and confirmed a minimum droplet temperature in the transition between globular and spray transfer. Arc characteristics of the Ni/WC consumable were unstable and the transition from globular to spray transfer was gradual without a distinct demarkation. For a 1.6 mm (0.0625 in.) tubular wire manufactured by H.C. Starck droplet heat content reached a minimum at approximately 190 A using a voltage setting of 26.9 V, 172 in/min wire feed speed, 12.5 mm (0.5 in.) electrode extension and 12.5 mm arc length. Subsequent bead-on-plate trials indicated increased carbide survival at the minimum droplet heat content compared with a similar overlay at non-optimum parameters. Small, polygonal secondary carbides were nucleated indicating dissolution and re-precipitation occurred even at the optimum parameters.

  • Subjects / Keywords
  • Graduation date
    Fall 2011
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.