Solidification: The Separation Theory and Its Practical Applications

ISBN-13: 9783540182337 / Angielski / Miękka / 1987 / 123 str.

Atsumi Ohno; Judy Wakabayashi

Opis

It was when I saw the countless number of icebergs floating in the North Atlantic Ocean in August 1964 that I decided to commence research into the solidification mechanism of metals, and already I have been continu ing this research for two decades. In 1970 my former professor Susumu Miyata received a letter from Pre sident Jiro Komatsu of the Tokyo Keigokin Seisaskusho Co., Ltd. The letter enclosed a copy of an article written by Mr. Imao Sasaki, chief of the casting research section at Daihatsu Motor Co., Ltd., entitled "Aruminyumu gyoko riron no shimpo" (Progress in aluminum solidi fication theory) from a journal called "Kinzoku Zairyo" (Metals in En gineering). This article introduced my research in considerable detail and well-written style. After stating that I "rebuffed conventional theories and enlightened casting engineers," Sasaki wrote that "These research results deserve great attention from casting engineers for the progress they have brought about in basic theories on improved soundness in casting quality." The letter from President Komatsu was a request to arrange a meeting with me. Saying that "I've heard you mention your theory occasionally, but I'd like to hear a full discussion of it for once," Professor Miyata accompanied me to the Tokyo Keigokin Seisakusho Co., Ltd. at Gyoda in Saitama Pre fecture."

Spis treści

1 The formation of cast structures.- 1.1 The macro structure of cast metal.- 1.2 Separation theory.- 1.2.1 Principal mechanism of the formation of equiaxed zone.- 1.2.2 Research motives.- 1.2.3 Precipitation of crystals along the mould wall.- 1.2.4 In-situ observations of the solidification phenomenon.- 1.2.5 Formation of the equiaxed zone.- 1.2.6 Separation theory and free chill crystal theory.- 1.2.7 Origin of showering crystals caused by cooling of the molten metal surface.- 1.2.8 Confirmation of the separation theory.- 1.3 Origin of the formation of equiaxed crystals.- 1.4 Formation and separation of equiaxed crystals.- 1.4.1 Growth of crystals on the mould wall.- 1.4.2 Growth of necked-shape crystals.- 1.4.3 Separation and multiplication of crystals.- 2 Controlling the macro structure of cast metals.- 2.1 Equiaxed crystal structure.- 2.1.1 Crystal grain refiners.- 2.1.2 Mould cooling capacity.- 2.1.3 Mould properties.- 2.1.4 Vibration.- 2.1.5 Stirring.- 2.1.6 Pouring temperature.- 2.2 Columnar structure.- 2.2.1 Unidirectional solidification.- 3 Application of the separation theory.- 3.1 Formation of the macro structure of eutectic alloys.- 3.1.1 Primary crystal distribution and equiaxed eutectic grains.- 3.1.2 Eutectic leading phase.- 3.1.3 Refining of equiaxed eutectic grains.- 3.1.4 Separation of eutectic grains from the mould wall.- 3.2 Solidification of cast iron and the creation of an inverse chill structure.- 3.3 Spherical graphite cast iron and the separation theory.- 3.4 Separation theory and macrosegregation.- 3.4.1 Normal segregation.- 3.4.2 Inverse segregation.- 3.4.3 String segregation.- 3.4.4 Band segregation.- 3.4.5 Gravity segregation.- 3.5 Separation theory and the O.C.C. Process.- Conclusion.- References.