Some Experimental Results by Micro-Tension Tester

This paper contains the following two experimental results obtained by “Micro-Tension Tester” recently provided in our labolatory. The size of the specimen was shown in Fig. 3. For the 1st experiment, notch toughness in the vicinity of welded part was investigated. In this study, a simplified method to judge the notch-sensitivity of material, which was suggested by one of the authors previously, was applied. The specimens were cut as shown in Fig. 6. From the test result shown in Fig. 8, it can be said, for both rimmed and killed steels, that (a) the notch toughness become worse as the part is far from the weld metal in the heat-affected zone and (b) far from this part the notch toughness recovers. For the 2nd experiment, the tensile terts of the eleven kinds of killed steels were performed, in each of three directions, i. e. rolling, transverse and thickness directions. Fig. 9 shows the schematic load-elongation curve of each direction. The experimental results were shown in Fig. 11 for all materials. From this figure, we know that tensile properties in the thickness direction are inferior to other two directions, especially in ductility.