The Development and Application of an Integrated VAR Process Model

[摘要] The VAR ingot has been the focus of several modelling efforts over the years with the result that the thermal regime in the ingot can be simulated quite realistically. Such models provide important insight into solidification of the ingot but present some significant challenges to the casual user such as a process engineer. To provide the process engineer with a tool to assist in the development of a melt practice, a comprehensive model of the complete VAR process has been developed. A radiation heat transfer simulation of the arc has been combined with electrode and ingot models to develop a platform which accepts typical operating variables (voltage, current, and gap) together with process parameters (electrode size, crucible size, orientation, water flow, etc.) as input data. The output consists of heat flow distributions and solidification parameters in the form of text, comma-separated value, and visual toolkit files. The resulting model has been used to examine the relationship between the assumed energy distribution in the arc and the actual energy flux which arrives at the ingot top surface. Utilizing heat balance information generated by the model, the effects of electrode-crucible orientation and arc gap have been explored with regard to the formation of ingot segregation defects.

[发布机构] MeltMet Technologies Unit 1205, 788 Humboldt St, Victoria; BC; V8W 4A2, Canada^1

[效力级别] 金属工艺学 [学科分类] 材料科学（综合）

[关键词] Comprehensive model;Development and applications;Energy distributions;Heat flow distribution;Operating variables;Process parameters;Solidification parameter;Thermal regimes