Abstract��By means of the metallographic examination of unqualified 9SiCr hot rolled bars by the ultrasonic inspection in Fushun Special Steel Co.��Ltd.�� it was found that the ultrasonic test defects were flake cracks and superheating cores. The flake in 9SiCr steel could be controlled by the fully baking of the ladles�� the hot charging annealing after rolling�� etc. The baking temperature of tundish should be more than 1 100 �棬 all the baking time should be no less than 3 hours�� the collection should be quick after rolling�� the collecting time should be no more than 15 minutes�� and the time for hot charging annealing or protective reheating should be no fewer than 36 hours. The arising of superheating core in 9SiCr steel could be reduced by controlling the heating temperature and holding time�� and the heating temperature of the casting couldn��t exceed 1 200 �� and the whole heating time should shorter than 2.5 hours.
����. 9SiCr�������ij�����̽�˲��ϸ�ķ��������[J]. �й������ڿ���, 2017, 35(1): 41-44.
LIU Gui-jiang. Analysis and control of unqualified 9SiCr hot rolled bar by the ultrasonic inspection. Chinese Journal of Iron and Steel, 2017, 35(1): 41-44.
2017, Vol. 35 
