Ib qho tsis xws luag: Tsis tuaj yeem nchuav Cov Nta: cov duab casting tsis tiav, cov npoo thiab cov ces kaum yog puag ncig, uas feem ntau pom hauv cov phab ntsa nyias. Yog vim li cas: 1. Iron kua oxygen yog hnyav, carbon thiab silicon cov ntsiab lus yog tsawg, sulfur ntsiab lus siab; 2. Tsawg pouring kub, qeeb pouring ceev ...
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