The Design And Implementation Of Control System For Wire-steel Heat Treatment Direct-fired Furnace

In the process of hard-drawing of the steel wire, it is becoming increasingly hard. At same time, the intensity raises either. Over the plastic nature and flexibility going down, the cold-working-hardening is generated, preventing the shape change further more. It can not be pulled out until it goes through heat processing after cold working hardening. Hence, heat treating furnace is a part of essential equipment in the producing process of hard-drawing of steel wire.The thesis is based on the current state of the electric muffle furnace in No.1 factory of Ningxia Hengli Steel Wire Rope Co., Ltd., illustrating the potential problem in the heating process of electric muffle furnace and the target to achieve that direct-fired furnace of the natural gas heat processing has been rectified. In order to energy saving and improve the destination of steel wire'quality, from the very beginning of technology of direct-fired furnace in heating process, the relationship of temperature and element of fume with oxidation carbon elimination of steel wire, and the relationship between the percentage of the containing volume of oxygen and the duty ratio of gas, the variety of furnace temperature and the gas flow are analyzed. The burning control strategy of direct-fired furnace is put on more emphasis, taking the fuzzy PID control strategy, Second generation cross-limit control theory and expert control strategy to modulate gas flow, air flow and the pressure of the furnace. The amplitude setting and control process of gas and air flow control loop are analyzed fully, as the mutual following relationship is ensured, the modulating speed of this system is accelerated, making it that the direct-fired furnace in heating process is at its best status. Through the analysis of the procedure parameters of the direct furnace in heating process, indicating that this system functions stable, the alternatives of the design is proper, the configuration of PLC system is reasonable, the computer program can be online modulated fluently, the temperature control of the furnace satisfy the technology requirement of the steel wire in heating process.The industrialized realization method of optimizing model of the direct-fired furnace in burning process is also discussed. The result of modulating process and simulating show that, the presented control strategy can improve the stability of the temperature of the furnace effectively, and offer a beneficial attempt of combustion control for the direct-fired furnace in heating process.