球铁铸管表面氧化夹杂物的消除措施

Measure to Eliminate Oxide Inclusion of Ductile Iron Cast Pipes

球铁铸管表面出现一种像是型砂被铁液烧结而产生的缺陷。根据这种分析,对型砂性能、浇注系统结构进行了改进,并对浇注温度进行了调整,但未能解决问题。最后认识到这种缺陷与型砂性能无关,因此并非是型砂烧结引起,而可能是铁液本身氧化产生的夹杂物缺陷;通过在铁液中加入稀土硅铁,降低铁液氧化倾向,彻底消除了这种缺陷。

There was some kind of surface defect found on the ductile iron cast pipes which looks like to be caused due to the molding sand sintered by the molten iron.Based on such analysis,both the properties of molding sand and the gating system were improved,and as well as the pouring temperature was adjusted.However,as the result,the defect still couldn＇t be completely eliminated.Test showed that this kind of defect couldn＇t be related to the molding sand,and therefore it was not caused due to the sintered sand and it was maybe some kind of inclusion produced due to the oxidation of the iron melt itself.Finally,by adding RESiFe alloy to decrease oxidizing tendency of the iron melt,the defect was completely eliminated.