1980 Vol 3. 4 A A Report Concerning the Cooperative Test Motohiko Nagai

This report presents the results of a cooperative test conducted to determine the yield strength of commercially pure titanium bars in Japan, addressing a gap in the Japanese Industrial Standards (JIS) which had not specified minimum yield strength values due to insufficient data. Our objective was to establish a standard method for determining yield strength and to provide reasonable values for classifying different material grades. The methodology involved testing materials from two out of three planned classes, as class 1 materials were unavailable. We collected data on mechanical properties and conducted tensile and hardness tests on the selected samples. The findings suggest that the effect of straining rate on yield strength is minimal, recommending a controlled straining rate between 0.30% and 0.70% per minute for ease of testing. Lastly, it was concluded that it is feasible to specify a minimum yield strength value for commercially pure titanium rods and bars that is consistent with the established values for sheets, plates, and strips.