1989 巻 (1989) 34 号 p. 59-84
When the Committee was organized, there were some opinions concerning the comprehensive method for the estimation of long-term setting properties from experimental short-time data. For this kind of problem it seemed indispensable for springs used at elevated temperatures, the Committee took up this as one of collaborative studies.
Fourteen affiliates participated in the comprehensive test in intermittent procedure to get 3, 000 hours setting properties up to 400°C on the two kinds of steel wire springs. The setting values or residual shear strain have an inclination not to saturate, but increase ever after the 3, 000 hours setting. Both the steel wire springs have a transition in setting behavior at a certain temperature level. On the test data up to 3, 000 hours, it was possible to express the residual shear strain as a constitutive equation. The equation can be used for extrapolation to predict long-time setting values.