Title:
METHOD FOR PREVENTING CRYSTALLIZATION OF CHUNKY GRAPHITE IN SPHEROIDAL GRAPHITE CAST IRON
Document Type and Number:
Japanese Patent JP3475607
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a large-size, thick-walled spheroidal graphite cast iron free from formation of chunky graphite by performing spheroidizing treatment by the use of an Mg spheroidizing material completely free from rare earth elements and further performing inoculation treatment by the use of an inoculate completely free from rare earth elements.
SOLUTION: A large-size, thick-walled spheroidal graphite cast iron, having ≥80mm wall thickness or ≥4cm modulus M, is produced. The crystallization of chunky graphite is mainly caused by REM. The purpose of the use of REM is (1) to compensate spheroidizing-inhibiting elements, (2) to inhibit the fading of Mg, (3) to increase the number of graphite grains, and (4) to inhibit Mg reaction by being added to an Mg type spheroidizing material. However, the purpose (1) is unnecessary because high purity scrap becomes easily obtainable and the precision of equipment for analysis is increased. Further, the purposes (2), (4) are unnecessary because spheroidizing temp. for the large-size, thick-walled spheroidal graphite cast iron is low and, as a result, the proceeding rate of fading is retarded and Mg reaction does not occur. Moreover, the purpose (3) is also unnecessary because the increase in the number of graphite grains is a problem in the case of a thick-walled product.
Inventors:
Haruki Itofuji
Ayumu Masutani
Ayumu Masutani
Application Number:
JP28061895A
Publication Date:
December 08, 2003
Filing Date:
October 27, 1995
Export Citation:
Assignee:
Ube Industries,Ltd.
International Classes:
B22D1/00; C21C1/10; (IPC1-7): C21C1/10; B22D1/00
Other References:
鋳物，日本，１９８５年，第５７巻第８号，５３４−５３５頁