| 摘要 |
PURPOSE:To set the conditions optimum for cooling of an ingot under a continuous casting mold in a short time with preparation of some sample in the above-described cooling, by determining the optimum values of the temps. in the non-worked and worked regions of the ingot through tension test with the ingot sample of the same steel kind. CONSTITUTION:In is necessary to maintain the temp. in the bent part of an ingot and the thermal hysteresis to attain said temp. in order to prevent the transverse crack of the ingot, and these temps. are represented by the ingot temp. T2 in the bent part and the lowest ingot temp. T1 right after the casting mold. Thereupon, a sample of the same steel component system as the steel kind intended for preventing transverse crack is heated to the melting temp. and is then cooled to and kept at the temp. T1. While the sample is reheated and kept to and at the temp. T2, the sample is subjected to a high temp. tension test, and such temp. regions of T1 and T2 at which the drawing value attains >=50% are determined. Since the shape of the test piece in this stage has a smaller influence on the drawing value as compared to the temps. T1, T2, an ordinary shape, for example, a round steel shape is satisfactory, and the above-mentioned time for holding the sample is allowed to approximately coincide with the time when the ingot receives heating in an actual machine. |
