CFD Modeling of Macro-segregation and Shrinkage During Solidification of Superalloy Castings
スポンサーリンク
概要
- 論文の詳細を見る
Minimizing macro-segregation during static casting of segregation prone alloys has always been a challenge. Over the years, alloy manufacturers have optimized the processing techniques for these alloys by balancing the total heat input of a casting and the rate of heat extraction from the casting surface. In this study, a computational fluid dynamics (CFD) code was used to develop a generic framework for studying macro-segregation and shrinkage in various casting processes. The code developed the framework by solving for the solid fraction evolution, micro-scale characteristics, temperature, flow and solute balance in multi-component alloy systems.Experiments were previously designed to measure solidification parameters using micro-probe compositional analysis. The thermo-physical properties of alloy 718 that were used in the simulations strongly depend on temperature. The partition coefficients of Nb, Ti, Al, and Mo in alloy 718 are also a strong function of temperature. They were determined based on quenching experiments during solidification of alloy 718.The model predictions were validated against measured macro-shrinkage and shrinkage porosities and against macro-segregation measured from pieces cut from both laboratory scale and industrials scale castings. A special segregation index was developed and then applied to properly assess the influence of material and process parameters on macro-segregation. The effect of Nb content and processing parameters such as super-heat, mold taper, mold type, and mold diameter on macro-segregation was also studied.Additional validation of the segregation model was performed using the literature analytical solution and experiments. Additional experimental validation of the model for prediction of macro-shrinkage and shrinkage porosities was performed using A356 plates cast in furan-silica sand molds.
論文 | ランダム
- 二重加盟に悩む幼稚園組織 (第34回日教組大会の討論にまなぶ(特集))
- 原子力を利用する南カリフォルニヤの海水淡水化計画
- 熱帯魚シクラソマにみられる虹彩の暗化について(行動・生態学)
- 熱帯魚Pelmatochonmis kribensisの社会順位の解析III. : 黒色物体に対する定位(行動学)
- 熱帯魚Pelmatochromis kribensisの社会順位の解析I. : "隠れ"順位の基本的要因について(生理)