Safe restarting of blast furnaces after major repair without preliminary hot-metal discharge from the well

Attention focuses on safety problems with blast-furnace housings that arise on restarting after major repair without preliminary hot-metal discharge from the well’s wear pits. A method of determining the threshold stress corresponding to industrial safety in different stages of furnace startup and operation is proposed. The identification of threshold stresses at which measures must be taken to improve the stress-strain state of the furnace housing at startup is discussed. For the example of blast furnace 7 at OAO ArcelorMittal Krivoi Rog, the dynamics of the stress-strain state in the metal framework of the furnace housing is considered, in the period from startup to the resumption of normal operating conditions.