Effect of Hydrogen Content and Mold Temperature on the Porosity of A356 Alloy Plate Castings

• Main Authors: L.C.Chan, 詹連池
• Other Authors: E.Chang
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/04077779923778176209

碩士 === 國立成功大學 === 材料科學(工程)研究所 === 83 === Thermal measurements were used to explore the porosity formation in cast alloy. In sand casting, the dimension of riser, and mold temperature of the castings were systematically varied obtain a wide range of thermal variations during the The Thermal variables together with changes of hydrogen content were correlated with the porosity content in the casting. The results show that small or without riser can cause non- directional solidification and negative thermal gradient and velocity values. During solidification, thermal gradient and solidification time increase and solidus velocity decreases with increasing dimension of riser. The porosity content was found to increase with decreasing thermal gradient and increasing solidus velocity and hydrogen content. Previous criterion of soundness unsoundness as a function of volume and freezing ratios is also to be dependent on the hydrogen content. An increase of hydrogen content moves the regime boundary upward and causes to produce sound casting more difficult, even for a casting designed with volume ratio and low freezing ratio.