Abstract
Rote and his colleagues in A. F. S. have suggested the fracture test to estimate melt quality of 85-5-5-5 red brass, and a few criticism is informed by some authers. The authers have already shown probable correlations between melt quality and fracture appearances of chill-blocks in the previous papers, and also indicated close relationships between fracture characteristics and amounts of dissolved gases in the metal.
In the present work, influences of casting conditions on the fracture appearances are deterimined to define the fracture testing process which will be applicable. Fracture appearances may be susceptible to variation in amounts of dissolved gases in the melt. Neverthless, depths of columnar and blue-grey patterns which are the most important variables in estimating the melt quality are affected by a little contamination of harmfull element such as aluminum and silicon, and this causes incorrect estimotion of the melt quality. A simple test to detect contaminations of alumlnum and silicon by means of observation of the surface apearances of cast blocks is also described.
A preferable way in which the melt quality may be evaluated includes observation of the surfaces of cast blocks to detect contaminatios and, if the melt is uncontaminated, fracture testing to determine amounts of dissolved gases in the melt.
