To provide a metal cast ingot for plastic working which satisfies the advantages that the yield of casting is high, teeming is facilitated, the variation in the weight of the stock is reduced, a meniscus is extremely reduced, the quality at the inside is satisfactory, dimensional precision is excellent or the like.
Regarding the metal cast ingot for plastic working, molten metal filled into a mold 2 including parts where a sprue 4 is closed after teeming, and also partitioned by an upper face, side faces and a lower face is solidified at least on the surface part in the mold, and the metallic structure in at least a part of the metal cast ingot 6 is composed of a crystal structure grown from the surface part to a direction almost parallel to the rising direction in the mold 2 on the upper face of the molten metal. Also, the surface of the cast ingot is free from cut faces, and, the are ratio of the structure having DAS (secondary dendrite arm spacing) (μm) in the range of 1.1 to 10.0 times to the DAS (μm) in the surface part furthest in the teeming direction from the sprue of the cast ingot is ≥70% to the area observed in the central longitudinal section of the cast ingot.
FUKUDA MASASHI
SUDO YOSHIAKI
KATO TAKAYUKI
Shinichi Fukuda
Takemichi Fukuda