黄銅の低融点介在物と鋳造割れ

抄録

  Hot tearing tests were carried out on α- and β-brasses containing elements to form low melting point inclusions such as Pb, Bi and P using a bar-shaped test mold. Si, Sn, Al, Ni and Fe were also added to alter the shape of lead particles and the solidifying structure in leaded β-brasses. Brasses containing Pb and Bi have granular low melting point inclusions and tear before completion of solidification of the primary phase. Brasses containing P have continuous low melting point inclusions along the grain boundary and tear during solidification. The brasses containing Pb and Bi have better resistance to hot tearing than those containing P. Secondary dendrite arms are slenderized and tear resistance is weakened in the β-brasses containing Si, Al and Sn. Fe grain refining successfully intensifies resistance of the leaded β-brasses to hot tearing.