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U.S. Department of Energy
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The effect of process perturbations on the local thermal environment in VAR alloy 718

Technical Report ·
OSTI ID:5837191
; ;  [1];  [2];  [3]
  1. Sandia National Labs., Albuquerque, NM (United States)
  2. Carpenter Technology Corp., Reading, PA (United States)
  3. Teledyne Allvac, Monroe, NC (United States)

Melt pool shape in VAR is controlled by fluid flow, which is governed by the balance between two opposing flow fields. At low melt currents, flow is dominated by thermal buoyancy. In these instances, metal is swept radially outward on the pool surface, resulting in relatively shallow melt pools but increased heat transfer to the crucible at the melt pool surface. At high melt currents, flow is primarily driven by magento-hydrodynamic forces. In these cases, the surface flow is radially inward and downward, resulting in a constricted arc, the pool depth and relative heat transfer to the crucible are intermediate, even though the melt rate is significantly lower than either diffuse arc condition. Constricted arc conditions also result in erratic heat transfer behavior and non-uniformities in pool shape.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
5837191
Report Number(s):
SAND-92-0593C; ON: DE92009067
Country of Publication:
United States
Language:
English