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Optimal beam pattern to maximize inclusion residence time in an electron beam melting hearth

Technical Report ·
DOI:https://doi.org/10.2172/432999· OSTI ID:432999
;  [1];  [2]
  1. Massachusetts Inst. of Tech., Cambridge, MA (United States)
  2. Sandia National Labs., Albuquerque, NM (United States)

Approximate probabilities of inclusion survival through an electron beam melting hearth are computed from nitride dissolution rates, flotation velocities, and residence times. Dissolution rates were determined by measuring shrinkage rates of pure TiN and nitrided sponge in small pools of molten titanium in an electron beam melting hearth. Flotation velocities were calculated using correlations for fluid flow around spheres, and show that particles sink or float unless their densities are extremely close to that of molten titanium. Flow field characteristics which lead to effective inclusion removal are discussed in terms of heat flux pattern required to produce them, based on the electron beam`s unique ability to impart a nearly arbitrary heat flux pattern to the melt surface.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC04-94AL85000
OSTI ID:
432999
Report Number(s):
SAND--97-0299C; CONF-970232--4; ON: DE97003028
Country of Publication:
United States
Language:
English