Observations of melt rate as a function of arc power, CO pressure, and electrode gap during vacuum consumable arc remelting of inconel 718
Statistically designed experiments were conducted at two different production melt shops to evaluate the influence of arc power, CO pressure, and electrode gap on melt rate. Appoximately 11,000 kg of Inconel 718 alloy 0.4 m diameter electrodes were vacuum consumable arc remelted into 0.5 m diameter ingots. Analysis of the experimental results revealed that melting efficiency (melting rate/kW) was maximized when CO pressure and electrode gap were held at low levels. Under these conditions, the heat distribution (created by the vacuum arc) on the electrode tip and the molten pool exhibited macro uniformity. Increased CO pressure and/or electrode gap depressed the melt rate, an at 13.3 Pa (100 microns) and a 0.050 m electrode gap, this depression exceeds 46 pct. Increasing these parameters also changed the arc behavior to that of a constricted arc with a highly localized heat input. It is hypothesized that the change from the usual diffuse arc to this constricted arc results in intense Lorentz pumping in a localized region of the molten pool atop the ingot causing fluid flow transients. These transients could, in turn, create solidification defects.
- Research Organization:
- Sandia Nation-1 Laboratories, Albuqueryue, NM
- OSTI ID:
- 6304077
- Journal Information:
- Metall. Trans., B; (United States), Vol. 15 B:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
INCONEL 718
VACUUM MELTING
CARBON MONOXIDE
EFFICIENCY
ELECTRIC ARCS
ELECTRODES
FABRICATION
MELTING POINTS
PARTIAL PRESSURE
PRESSURE EFFECTS
SOLIDIFICATION
THERMODYNAMICS
ALLOYS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHROMIUM ALLOYS
CURRENTS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
INCONEL ALLOYS
MELTING
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
360102* - Metals & Alloys- Structure & Phase Studies
360101 - Metals & Alloys- Preparation & Fabrication