铸铁凝固期间电阻率的变化

作者们通过测量变压器式传感器中一次线圈内电流随时间的变化，研究了亚共晶白口铁、灰铸铁和稀土镁铸铁凝固期间电阻率的变化。发现，随着凝固行径和凝固过程中析出相的结晶构造不同，各种铸铁的电阻率变化特点也有很大差别。奥氏体和球状石墨的析出会造成试样电阻的降低或传播器一次线圈电流的升高，而莱氏体和片状石墨则引起相反的变化，在铸铁内所有的相和组成物中，石墨是决定电阻率变化的主要因素。作者们深信，本文所报导的实验结果有助于铸铁凝固机理的研究和生产过程的控制。

Changes in Electrical Resistivity of Cast Irons During Solidification

By measuring the change in current with time in the primary coil of a transformer-type sensor, the authors investigated the change in the electrical resistivity of hypo-eutectic white cast iron, grey cast iron and rare-earth magnesium cast iron during solidification. It has been found that the features of these changes of various cast irons are quite different, depending on the behavior of solidification and the crystal structure of the phase crystallizing in the course of solidification. The crystallization of austenite and spheroidal graphite will cause a decrease in the resistance of specimen, or a current increase in the primary coil, while ledeburite or flaky graphite brings about a change in opposite direction. Among all phases present in cast iron, the graphite is a predominant factor determining the change in resistivity. It is convinced that the results reported in this paper are helpful to the study of solidification mechanism and production control of cast iron.