中実円柱試験片による直接加熱方式熱疲労試験 : 高温強度特集号

概要

論文の詳細を見る
In recent years the problem of thermal fatigue of heat-resisting metallic materials has received attention and several reseachers have performed fundamental works in this line. There are, however, several open questions as to the fundamental method of testing with which thermal fatigue strength is evaluated. One of the questions is the problem on the shape of test specimen. In conventional thermal fatigue tests thin walled hollow specimen is adopted, but in a few cases solid cylindrical specimen is employed because in case of the former specimen there is difficulty in machining of test specimen from tool steel or roller steel. However, the adoption of solid cylindrical test specimen is not fully developed because of unstable deformation of test specimen during thermal fatigue test, although preparation of solid specimen is much easier than hollow specimen. In this connection it is necessary to verify the adoption of solid cylindrical specimen. The authors, as well, have been interested in the problem concerned with this unstable deformation of solid test specimen for thermal fatigue test. In the present paper, results of thermal fatigue test with two sorts of solid cylindrical specimens are presented and these are compared with the results of thin walled hollow specimen. Materials tested are AISI 347 type stainless steel and 2・25 Cr-1 Mo steel. The test results are arranged in two sorts of presentation, i.e. the thermal strain amplitudenumber of cycles and the thermal stress amplitude-number of cycles relations, in order to compare the strength of solid specimen and hollow specimen in thermal fatigue. It is found that the two sorts of solid cylindrical specimen have different lifetimes. In the solid specimen with shorter length the distribution of temperature along the length was farely uniform, while in the cases of solid specimen with longer length and hollow specimen the temperature was considerably high in and around the central part as compared with that at the end portion of parallel length. However, during the thermal fatigue process of the solid specimen of longer length, unstable deformation, i.e. bulge of specimen near mid length, was observed, while the solid specimen with shorter length did not show such a feature. This is considered to have brought about the difference of lifetime. The results of the present study are summerized as follows : the solid cylindrical test specimen is available as the specimen for thermal fatigue test, where electric current is passed through the specimen as heating source, provided that attention were laid on minimizing the temperature variation along length. The test results of solid cylindrical specimen give a good agreement with those of thin walled hollow specimen on both base of thermal strain amplitude and thermal stress amplitude.
1962-03-15

中実円柱試験片による直接加熱方式熱疲労試験 : 高温強度特集号

スポンサーリンク

概要

著者

関連論文

スポンサーリンク