Development of lead-free copper alloy-graphite castings. Technical report, January 1994--December 1994
Water model experiments were conducted to develop a two-stage stirring method for obtaining higher yields and a more uniform distribution of graphite particles in copper alloys. This was followed by several melts for synthesis of copper-graphite alloys in which Ti was used as a wetting agent to improve the wettability of graphite in the copper melt. In the first stage, a vortex method was employed to facilitate the addition of graphite particles into the copper melt. In the second stage, a specially designed stirrer was used for uniform particle distribution while avoiding the formation of vortex in the melt. The two-stage stirring was found to considerably improve the recovery of graphite, over those obtained with the prior practice of single-stage stirring and resulting in a more uniform particle distribution. In addition, graphite recoveries increased with increasing Ti content in the range investigated. Floatation, fluidity, and directional solidification experiments were also conducted on copper-graphite alloys synthesized in this study. Fluidity tests showed that the spiral fluidity length of the yellow brass alloy increased with temperature and decreased with graphite. The fluidity of copper-graphite alloys investigated to-date remained adequate to make a variety of castings. The observations of casting microstructure under directional solidification and floatation showed that in certain castings the graphite particles remained agglomerated, and they readily floated to the upper part of the castings where they reduced the size of gains. However, even in the agglomerated form, the graphite particles improved the machinability of copper alloys in a manner similar to lead. The results of the first year work provide an improved method of synthesis of lead free copper graphite alloys with improved machinability and adequate fluidity.
- Research Organization:
- Wisconsin Univ., Milwaukee, WI (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FC07-93ID13236
- OSTI ID:
- 83843
- Report Number(s):
- DOE/ID/13236-T1; ON: DE95015157; TRN: 95:005420
- Resource Relation:
- Other Information: PBD: [1995]
- Country of Publication:
- United States
- Language:
- English
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