Effect of Quenching Heat-treatment on Mechanical Properties and Microstructure of Modified C95600 Bronze

doi:2011.25.6.97

J. Ocean Eng. Technol. > Volume 25(6); 2011 > Article

J. Ocean Eng. Technol. 2011;25(6):97-104.
DOI: https://doi.org/10.5574/KSOE.2011.25.6.097

Lee Sung-Yul,Moon Kyung-Man,Oh Jae-Hwan,Shin Dong-Il

Department of Marine Equipment Engineering Korea Maritime University,Department of Marine Equipment Engineering Korea Maritime University,Graduate School of Korea maritime University,Graduate School of Korea maritime University

Keywords: Modified C95600 bronze, C95600, Quenching, Mechanical properties, Hardness, Microstructure

Abstract

Modified C95600 bronze contains Fe component of 0.7 weight percentage besides Cu-7Al-2.5Si composition. The shape of centrifugal cast is a circular pipe with thick wall. Specimens machined from the centrifugal cast were quenched in oil after isothermal holding at a given heat treatment temperature in the range of $700{sim}900^{circ}C$. Mechanical properties and structural morphology are depended on the quenching heat treatment temperature regardless of isothermal holding time. Tensile strength or Brinell hardness is increased with increasing heat treatment temperature. The microstructure caused by quenching contains mixing phases of ${alpha}+{eta}'+FeSi+{kappa}$ which martensite of ${eta}'$ phase has been transformed from ${eta}$ phase. Effect of isothermal holding temperature on mechanical properties in case of quenching heat treatment attributes to the change of volume fraction of ${eta}'$ on the structural morphology. Mechanical characteristics of specimen, initially quenched from $850^{circ}C$, and then tempered at $500^{circ}C$, does not show an obvious softening indication, because disappearance of ${eta}'$ during tempering process can be compensated by precipitation of brittle phase ${gamma}$.