Structure Control and Characteristics of Solidification on Sulfide Dispersed Lead-Free Bronze Castings

• Published in: Chūzō kōgaku Vol. 81; no. 12; pp. 650 - 660
• Main Authors: Kobayashi, Takeshi, Akashi, Iwao, Maruyama, Tooru, Abe, Hiroyuki, Sugitani, Takashi, Wakai, Hiroaki
• Format: Journal Article
• Language: Chinese; Japanese
• Published: Japan Foundry Engineering Society 25.12.2009
• Subjects: activity of S; bronze; castings; Cu-Cu2S system; disperse; lead-free; sulfide
• ISSN: 1342-0429; 2185-5374
• DOI: 10.11279/jfes.81.650

  When copper sulfide is directly crystallized from copper alloy melt, sulfide floats and separates because of the low density. The purpose of this study was therefore to reduce the activity of sulfur (S) by solidification of the semistable system (monotectic system) in the double equilibrium diagram of the Cu-Cu2S system and disperse the spheroidal sulfide. The properties of sulfide dispersed lead-free bronze castings in the cooling and heating processes were examined. The results of investigations on the mass effect of lead-free bronze castings were as follows. (A) When Ni was added (Ni≤1mass%) and solidified in the monotectic system in the double equilibrium diagram of the Cu-Cu2S system to reduce the activity of S, it was possible to crystallize fine spheroidal sulfide in the Cu (α) dendrite clearance and prevent flotation and separation. (B) Spheroidal sulfide in the heating process did not float and separate because it was fused together with Cu (α) from the beginning. (C) Sulfide dispersed lead-free bronze castings had the same mass effect as many copper alloys.