Abstract
In previous papers, authors studied the difference in value of tension test on the test specimens taken from the standard Y-block and the actual body of castings and, especially, the large difference in elongation in as-cast iron. This was due to the manner of solidification of iron. Hence, authors conducted to find out the difference in the value between specimens taken from the bottom and center of Y-block. The experiments were made on ordinary or stainless steel castings and spheroidal graphite and ordinary cast iron (Table 1), using the Y-block in Fig. 1 (as a reference, the plate-like specimens in Fig. 2 and the ordinary cast iron specimen in Fig. 3 were tested as well.). These results are given in Tables 2-8 and they can be summarized as follows :
(1) In the as-cast ordinary or stainless steel castings, the strength of the test specimens taken from the center of the Y-block was 95-99.5% of that from the bottom, while the elongation of the former was 77.5-82% of that of the latter. In the spheroidal graphite cast iron, these ratios were about 90.5% on the strength and about 50% on the elongation.
(2) This was caused by the difference in the freezing manner indicated by the comparison of cooling curves in Figs. 4-7. Also, it seems from the observation of the microstructure that intricate crystal-configurations may be a factor causing the drop in the value of strength and elongation.
