PREPARATION OF CRFE ALLOYS,
Abstract
High purity, homogeneous samples were prepared for a study of the thermoelectric power and electrical resistivity of the CrFe system. The use of an induction heater for making these samples at first appeared to be ideal because of its ability to generate high temperature and its magnetic stirring properties. However, the chromium component of the molten alloy at this temperature is quite reactive, and a crucible material was not found that would remain inert and intact. The next device that was tried, an arc furnace, did fill the requirement of being able to contain the melt without reacting with it. The samples were successfully melted on a water-cooled copper hearth with an arc initiated from a water-cooled tungsten tip, under one-half atmosphere of argon. The samples made were of 5-9's purity and were homogeneous to within plus or minus 0.2% of their entire volume of some 2 cc. Further difficulty was encountered in reducing the rough, as-cast ingot to a usable geometry. In this case a uniform cylinder was desired of approximately 1/8-inch diameter and 2-1/2-inch length. This difficulty was overcome by spark-erosion machining of the rough ingot to near cylindrical form, followed by centerless grinding to a perfect cylinder. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 05, 1966
- Accession Number
- AD0641896
Entities
People
- J. E. Cox
Organizations
- United States Naval Research Laboratory