低B含量細晶劑對1000系鋁合金鑄造時的影響

1000系的鋁合金由於純度較高，其內所含協助鑄造時晶粒細化的雜質含量相對偏低，因此在鑄造時晶粒組織的細化作用不易達成，而需添加細晶劑以提供足量的異相結晶種顆粒，來細化鑄造時的晶粒組織。此類細晶劑大都含有高量的B及TiB_2細晶種顆粒，可是TiB_2細晶種顆粒很容易和氧化渣結合而形成夾渣缺陷，此類夾渣缺陷雖然含量很少，且對成品機械性質沒有明顯的影響，但是對要求高表面品質的產品，卻會造成很多的表面條紋刮痕缺陷問題。為了避免此種缺陷問題的產生，在澆鑄有高表面品質需求的產品所用之原料鋁胚時，只能添加TiB_2細晶種顆粒含量較少的低B含量細晶劑，來進行鋁胚晶粒組織細化的處理。低B含量的細晶劑有相當多種類，而且生產的廠商也不止一家，不同廠商及種類的細晶劑對1000系鋁合金的鑄造晶粒細化效果也不明瞭。因此本研究乃針對兩家廠商所生產的兩種低B含量細晶劑，對1070鋁種鑄造時晶粒細化的效果進行探討，並和常用的高B含量細晶劑及AI-6Ti-0.02C細晶劑在鑄造時晶粒細化的效果相互比較。由本研究可得知，細晶劑的晶粒細化能力不但和其成份有關，亦和細晶劑製造廠商的製程能力有關。

關鍵字

細晶劑；晶粒細化效果；氧化物夾渣；表面條紋刮痕

並列摘要

The 1000 series aluminum and alloys are very difficult to get grain refined due to low impurity content. It is a common practice to introduce grain refiner into the melt during ingot or slab casting. Most kind of grain refiners contain B and TiB_2 nucleus particles. The TiB_2 nuclei are easy to combine with oxides and form big oxide inclusions. These inclusions are detrimental to the surface quality of surface-sensitive products and will induce a lot of scratches on the product surface. In order to avoid this kind of defect, low B content grain refiner is used to do the grain refining work. There are many kinds of low B content grain refiners manufactured by different producers. The grain refining effects of these low B content grain refiners varied and were not known yet. This study compared the grain refining effects of these grain refiners with each other. Then we also compared their grain refining effect with those of the commonly used high B content grain refiner and Al-6Ti-0.02C grain refiner. From this study it was found that the grain refining effect of the grain refiners were not only dependent on their compositions but also on the manufacturers.

並列關鍵字

Grain refiner ； Grain refining effect ； Oxide inclusion ； Surface scratch

國際替代計量

低B含量細晶劑對1000系鋁合金鑄造時的影響

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