フェライト基地球状黒鉛鋳鉄の低温における静的及び動的3点曲げ特性 Static and Dynamic Three-Point Bending Characteristics of Ferritic Spheroidal Graphite Cast Iron at Low Temperature
Static and dynamic bending tests of ferritic spheroidal graphite cast iron were carried out at temperatures range from room temperature to 77K. Bending load-time curves obtained by using instrumented Charpy impact testing machine are converted to load-deflection curves. The relationship between bending load <i>P</i> and deflection <i>δ</i> is well expressed by <i>P</i>=<i>Dδ<sup>n</sup></i> in both of static and dynamic tests, where <i>D</i> and <i>n</i>’ are constants. <i>D</i> and <i>n</i>’ obtained are both larger than the expected respectively. Constant <i>D</i> in dynamic test is larger than that in static at the same temperature by 17%, regardless of the testing temperature. This difference coincides pretty well with the measured strain rate exponent of flow stress 0.0103. The critical deflection just before fracture <i>δ</i><sub>c</sub>, is proportional to fracture strain of specimen at loading point. Fracture energy <i>W</i>, the area surrounded by the load-deflection curve and abscissa graphically, can be numerated by <i>W</i> = <i>P</i>m<i>δ</i><sub>c</sub> / (1 + <i>n</i>’), where <i>P</i><sub>m</sub> denotes the maximum bending load. The strain rate dependence of transition temperature for the iron seems roughly similar to that of steel.
- 鋳造工学 = Journal of Japan Foundry Engineering Society
鋳造工学 = Journal of Japan Foundry Engineering Society 70(8), 563-568, 1998-08