CAJ | 학술논문

皮下气孔是球铁件常见的铸造缺陷之一，其形成机理至今说法不一．既然非金属夹杂物伴随气泡一并迁移，那么，检测铸件各部位的镁含量势必能够追踪到气泡的迁移路径，从而能够对其运动过程作出分析．检测结果表明，铸件内部的镁含量由外而内呈梯度增加，铸件表面的氧化皮中富含镁元素．研究表明，皮下气孔由不能外逸的气泡形成，其外逸阻力来自于已经凝固的氧化膜，提高碳当量有助于增强石墨化膨胀能力，从而存氧化结膜前将气泡尽快挤出金属液，避免皮下气孔的产生．
피하기공시구철건상견적주조결함지일，기형성궤리지금설법불일．기연비금속협잡물반수기포일병천이，나요，검측주건각부위적미함량세필능구추종도기포적천이로경，종이능구대기운동과정작출분석．검측결과표명，주건내부적미함량유외이내정제도증가，주건표면적양화피중부함미원소．연구표명，피하기공유불능외일적기포형성，기외일조력래자우이경응고적양화막，제고탄당량유조우증강석묵화팽창능력，종이존양화결막전장기포진쾌제출금속액，피면피하기공적산생．
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.