Furnace pressure control method during continuous annealing of stainless steel

Abstract

The invention discloses a furnace pressure control method during continuous annealing of stainless steel, which can improve the hearth pressure detection accuracy, ensure the safety of equipment, and improve the continuous operation capability of the production line, wherein the furnace pressure control method comprises the following steps: step one, installing pressure transmitters on a working side and a driving side of a last hearth; step two, transmitting 4-20mA signals sent by the pressure transmitters to a PLC (Programmable Logic Controller) analog input module of an annealing furnace by a signal cable; step three, obtaining three pressure values as follows: a hearth pressure PT01 on the working side, a hearth pressure PT02 on the driving side and an average PT03 of PT01 and PT02, by PLC program conversion and calculation; and step four, compiling a PLC program and HMI (Human Machine Interface) software. The furnace pressure control method during continuous annealing of stainless steel has the advantages that the furnace detection accuracy is improved, the pressure detection value is closer to the actual furnace pressure due to two-point sampling and averaging, and the safety of the equipment is enhanced.

Description

technical field [0001] The invention relates to a furnace pressure control method during continuous annealing of stainless steel. Background technique [0002] The horizontal furnace for continuous annealing of cold-rolled stainless steel is a relatively common heating furnace. The furnace is divided into several zones along the direction of strip steel travel. The pressure in the furnace is taken as a reference by the value detected by the pressure detection instrument (pressure transmitter), and the speed of the exhaust fan is controlled by PLC (some annealing furnaces are also equipped with dampers controlled by analog signals) to increase or decrease to achieve The state of slight negative pressure in the furnace. [0003] The function of furnace pressure control is mainly to keep the pressure in the furnace at a slight negative pressure, that is, in the range of less than or equal to 0 relative to the atmospheric pressure. When the furnace pressure is high (greater th...

AI Technical Summary

Problems solved by technology

[0005] The disadvantage of the single-point sampling method is that the single-point sampling has limitations, and there is a certain deviation between the detected pressure value and the actual pressure; when there is a pressure transmitter failure or a blockage of the sampling pipe, etc. , production line stop

At this time, there is no guarantee that the production line will continue to run, and we can only wait for the fault to be resolved

It will cause strip defects in the furnace and other process sections, resulting in defective products and large losses; when the pressure transmitter fails to reach the high and low alarm values ​​due to various reasons, the operator is not easy to detect , may cause hot air to overflow, damage peripheral equipment, or cause the exhaust fan to run at high speed, thus wasting energy