METHOD OF CONTROLLING STEEL STRIP TEMPERATURE IN CONTINUOUS HEATING EQUIPMENT

摘要

A method of controlling steel strip temperature in continuously heating steel strip in heating equipment having a preheating zone and a fast-heating zone. The preheating zone comprises a number of gas-injecting preheating units that can individually be put into and out of operation at will. The in-operation length of the preheating zone is prefixed irrespective of strip thickness. The tempera-ture of the fast-heating zone is preset according to strip thickness so that the strip acquires the desired temperature at the exit end thereof. In regular opera-tion threading strip of a given thickness, the strip is preheated in the preheat-ing zone of the prefixed in-operation length and rapidly heated in the fast-heat-ing zone at the preset temperature. In irregular operation, such as threading strip of varying thickness, the temperature of the fast-heating zone is changed from the one preset for the preceding strip to a second one optimum for the following strip. There is a transitional period in which the preset temperature of the fast-heating zone changes to the second one. During this period, the in-operation length of the preheating zone is adjusted to control the strip tempera-ture at the exit end thereof. Thus the desired strip temperature at the exit end of the fast-heating zone can be assured irrespective of strip thickness.