AC2BS합금의 열간 균열강도 및 인장특성에 미치는 스크랩 함량의 영향

Abstract

The effects of scrap content on the hot tearing property and tensile property were investigated in AC2BS alloy. The hot tearing strengths were <TEX>$16.4kgf/cm^2$</TEX>, <TEX>$15.2kgf/cm^2$</TEX>, <TEX>$14.9kgf/cm^2$</TEX> and <TEX>$13.3kgf/cm^2$</TEX>, respectively, under the constant solid fraction of 29.3% when the scrap contents of the specimens were 0%, 20%, 35% and 50%. In the same way, tensile strengths of the as-cast condition were <TEX>$24.5kgf/mm^2$</TEX>, <TEX>$23.7kgf/mm^2$</TEX>, <TEX>$17.3kgf/mm^2$</TEX> and <TEX>$16.0kgf/mm^2$</TEX>, respectively, and the corresponding tensile strengths of the T6 heat treatment condition were <TEX>$27.2kgf/mm^2$</TEX>, <TEX>$26.7kgf/mm^2$</TEX>, <TEX>$24.2kgf/mm^2$</TEX> and <TEX>$23.9kgf/mm^2$</TEX>. Hot tearing strength and tensile strength decreased as scrap content of the specimen increased. According to the evaluation of the quantitative hot tearing and tensile test results, the decrease of these strengths is due to the presence of oxide films which act as crack initiation site of the specimens. Therefore, elimination of oxide films of aluminum melt to maintain melt cleanliness is required.