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Dai H.,Ningbo University | Ma Y.,Ningbo University | Zhang X.,Ningbo University | Pan J.,Ningbo University | And 6 more authors.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2010

HPb58-2A dodecagon abnormal-shape tubes with 5 mm in the smallest thickness and crack free was produced with recycled scrap cooper by continuous casting at 950'C and 180-350 mm/min in condition of cooling at 40'C. Microstructure of the tubes was analyzed by optical microscope (OM), SEM (scanning electron microscope) and EDS (energy dispersive spectrum). The results reveal that Fe based solid solution is formed into dendrite due to exhibiting preferred growth with mass ratio of Si via Fe increasing to 0.078, while with mass ratio of Si via Fe of 0. 178, Fe-Si phase shows polygonal structure, a phase is solidified ahead to β phase , which results in the higher Pb concentration in latter solidified β phase and the highest ones in interface of o phase and β phase. During cooling process, Pb particles is dispersedly grown in o phase and β phase, and size of Pb particles in both a phase and in β phase are less than 0. 5μm and 0. 75μm, respectively. In addition, size of Pb particles exhibiting rosette structure in the β phase in interface reaches up to 2. 5 μm. Fine Pb particle can not only ensure excellent cutting performance but also increase mechanical properties of continuous casting abnormalshape tubes.

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