| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an overlay method for a cast iron base material where an overlay layer having reduced gas defects is easily and stably obtained by suppressing gasification of graphite without performing the troublesome setting of overlay conditions and pretreatment. <P>SOLUTION: The area ratio of flaky graphite in the structure of a cast iron base material as an object for overlay is suppressed to≤10%, and further, the maximum length of the flaky graphite is suppressed to≤140μm. By suppressing the area ratio of the graphite, the total amount of the gas to be generated is suppressed, and an excessive gasification preventive countermeasure is eliminated. Further, smaller the degree of reducing the dimensions of individual graphite, smaller the amount of the gas to be generated from each graphite, and thus, even if gas defects such as pinholes and blowholes are generated in an overlay layer, the size of the gas defects is small. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
