The ductile cast-iron pipe and its production manner null C due to centrifugal force

摘要

PROBLEM TO BE SOLVED: To attain the improvement of quality of ductile cast iron tube by a centrifugal casting method and the simplification of the process. ;SOLUTION: The cast iron tube has components containing 3.0 to 4.0% C, 1.5 to 3.0% Si, 0.1 to 0.4% Mn, ≤0.05% P and ≤0.01% S, and the balance Fe, and further containing 0.0005 to 0.05% Bi, in particular, and, more preferably, containing 0.0001 to 0.05% Ca. The cast iron tube has a dense and tough structure in which many spheroidal graphite is crystallized into a ferrite based matrix while maintaining a spheroidization rate of ≥90%, so that ferritizing annealing after casting can be performed at a lower temperature, and/or can be performed in a short time.;COPYRIGHT: (C)2003,JPO