2001 Volume 87 Issue 11 Pages 713-718
The authors developed a weight-dropping impact testing machine which evaluates the toughness of materials under tensile impact loading. The relation between the time t and load P is measured with the developed testing machine. The impact strength σmax, is determined from the maximum load P max; impulse F s from the time t and load P. Also, the "impulsivity Tim"-the ratio of the material impulse F s to the standard impulse F ss calculated by means of the maximum load P max-is defined. A toughness evaluation method based on the relationship between the impact strength σmaxand the "impulsivity Tim" was reported in a previous paper. In this paper, heat treated S45C, well known for its static mechanical properties and Charpy impact value, is used as the specimen in the developed testing machine. It is confirmed that the developed testing machine is useful as a toughness evaluation method under tensile impact loading.