METHOD FOR PRODUCING GRAY CAST IRON EXCELLENT IN VIBRATION DAMPING PERFORMANCE AND STRENGTH

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a gray cast iron excellent in vibration damping performance and strength with which both of the vibration damping performance and the strength can be obtained in as-cast without applying induction-hardening heat treatment.;SOLUTION: This method for producing the gray cast iron, is performed, with which firstly, mixture mixing sand grains and resins is formed and a shell-mold sand mold for promoting the cooling having resin-enrich portion set to ≥4.0% of weight ratio of the resin content on at least surface layer, is prepared. Successively, this shell-mold sand mold is set in the mold and the resin-enrich portion of the shell-mold sand mold is faced to the portion promoting the cooling of the molten iron in a casting cavity, and the molten iron is poured into the casting cavity in the mold and solidified, and the gray cast iron excellent in the vibration damping performance and the strength by dispersing flaky graphite in a matrix, is formed. Further, this gray cast iron has the cast iron surface layer having ≤8μm average graphite length and ≥90% pearite area ratio, and has the cast iron inner layer having ≥90% pearite area ratio.;COPYRIGHT: (C)2004,JPO&NCIPI