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Study on Formation Mechanism of Blowholes in Nodular Cast Iron(PDF)

南京师范大学学报（工程技术版）[ISSN:1006-6977/CN:61-1281/TN]

Issue:
2012年04期
Page:
78-81
Research Field:
Publishing date:

Info

Title:
Study on Formation Mechanism of Blowholes in Nodular Cast Iron
Author(s):
Sun Shaodong1; Zhang Mengqun2; Ma Xiang2; He Shijian1; Wan Suwen1
1.Mechanical & Electrical Engineering Department,Huaian College of Information Technology,Huaian 223003,China
Keywords:
nodular cast iron;  subcutaneous blowhole; bubble transfer;  graphitization expansion;  oxide film
PACS:
TG255
DOI:
-
Abstract:
The subcutaneous blowhole is one of defects in nodular cast iron，and its formation mechanism has no final conclusion in the area of foundry technology． Because non-metallic inclusion always transfers in metal liquid together with bubbles，we believe that determinations of magnesium in different inner parts of a casting will be helpful in analyzing the motion paths of bubbles migration． The testing results have shown that the magnesium content gradually increases from the surface to the center of the casting，and the oxide film has shown enrichment of magnesium and sulfur． Our study shows that the oxide films hinder the bubbles to transfer outward and those stranded bubbles form subcutaneous blowholes． Increasing of carbon equivalent will raise the graphitization expansion property， and in the meanwhile accelerate the bubbles transfer， so， the subcutaneous blowholes will be avoided．

References:

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Last Update: 2013-03-21