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再生废杂铜在结晶器冷却水为40℃左右、950℃保温、以180～350mm/min连铸得到无裂纹的十二边形、最小壁厚为5mm的HPb58-2A异型管材;经金相、扫描电镜观察和能谱成分分析,结果表明,当相成分中w(Si)/w(Fe)为0.100以下时,初生相Fe基固溶体具有择优生长方向,形成树枝晶;当w(Si)/w(Fe)为0.178时,Fe-Si相形貌为多边形;α和β相先后凝固析出,两者同时向熔液中析出Pb,因此在后凝固的β相中Pb浓度较大,在α和β相交界处Pb浓度最大。在冷却过程中,Pb在α和β相中弥散长大,且在α和β相中Pb粒尺寸分别小于0.5μm和0.75μm,在两相交界处的β相中,Pb呈花瓣状,尺寸最大为2.5μm;细小的Pb粒使连铸异型管材在具有高的切削性能的同时还具有更高的力学性能。
Recycled scrap copper in the mold cooling water is about 40 ℃, 950 ℃ insulation to 180 ~ 350mm / min continuous casting without cracked dodecahedron, the minimum wall thickness of 5mm HPb58-2A shaped pipe; the metallographic , Scanning electron microscopy (SEM) and energy spectrum analysis. The results show that when the content of w (Si) / w (Fe) is 0.100 or less, the primary phase Fe-based solid solution has the preferred growth direction and forms dendrites. / Fe (Fe) is 0.178, the morphology of the Fe-Si phase is polygonal. The α and β phases are solidified and precipitated simultaneously, and both precipitate Pb simultaneously to the melt. Therefore, the Pb concentration in the post- Pb concentration at the junction of α and β is the largest. During the cooling process, Pb diffuses and grows in the α and β phases, and Pb particle sizes in the α and β phases are less than 0.5 μm and 0.75 μm, respectively. In the β phase at the two-phase junction, Pb is petaloid, A maximum of 2.5μm; fine Pb particles so that the continuous casting of special-shaped pipe with high cutting performance but also have higher mechanical properties.