Heat treating the strips, sheets or wires made of steel, in batch, in form of coil, comprises cooling the batch in first and second cooling phases, and discharging inert gas from furnace chamber in second cooling phase

摘要

The method for heat treatment of strips, sheets or wires made of steel, in a batch, in the form of a coil under an inert gas in a furnace chamber, comprises cooling the batch in a first cooling phase and a second cooling phase with different cooling rates according to a heating phase, discharging inert gas from the furnace chamber in the second cooling phase and then cooling in a heat exchanger by delivering heat to a heat carrier, and recycling the inert gas in the furnace chamber. The heat carrier is a temperature-resistant liquid heat transfer medium such as thermal oil. The method for heat treatment of strips, sheets or wires made of steel, in a batch, in the form of a coil under an inert gas in a furnace chamber, comprises cooling the batch in a first cooling phase and a second cooling phase with different cooling rates according to a heating phase, discharging inert gas from the furnace chamber in the second cooling phase and then cooling in a heat exchanger by delivering heat to a heat carrier, and recycling the inert gas in the furnace chamber. The heat carrier is a temperature-resistant liquid heat transfer medium such as thermal oil. The batch is slowly cooled in the first cooling phase over several hours, and the inert gas, in the first cooling phase, delivers heat to the heat carrier present in the heat exchanger. The heat carrier flows into a first heat transfer circuit A by a first heat exchanger for decoupling heat on high temperature level of the batch or into a second heat transfer circuit B by a second heat exchanger for decoupling heat on a low temperature level of the batch. The decoupling of heat by the first heat exchanger integrated in the first heat transfer circuit A is started when the batch temperature is 550[deg] C. Heat is transferred to an energy conversion system, to convert the heat into electric energy, by the first heat exchanger integrated in the first heat transfer circuit A. The volume flow of the heat carrier in the first heat transfer circuit A is lower than the volume flow of the heat carrier in the second heat transfer circuit B. An independent claim is included for a system for heat treatment of strips, sheets or wires made of steel in a batch in the form of a coil under an inert gas in a furnace chamber.