Automatic Control System

1. Equipment Positioning

Centered on PLC, the heat treatment automation system is matched with HMI human-machine interfaces, sensors and actuators to realize closed-loop automatic control of the whole process including heating, conveying, atmosphere and cooling of the entire production line. It replaces manual operation, stabilizes process parameters, realizes production data traceability and automatic fault early warning, compatible with various continuous and batch heat treatment furnaces.

2. System Hardware Composition

1. Main Control Unit

Industrial-grade PLC (redundant hot standby models can be selected to guarantee non-stop production), responsible for logic operation, PID temperature control, equipment linkage and fault judgment; supports storage of multi-segment process curves and one-click switching of multiple formulas.

2. Human-machine Interaction Unit (HMI Touch Screen)

Real-time display of furnace temperature, cooling medium temperature, roller speed, atmospheric oxygen content, water & oil pressure and equipment operating status; supports modification of process parameters, curve retrieval, production report inquiry and pop-up fault prompts.

3. Signal Acquisition Sensing Unit

Thermocouples, infrared pyrometers, oxygen probes, dew point meters, pressure transmitters, liquid level sensors, photoelectric switches, encoders and gas concentration detectors collect real-time signals of temperature, flow rate, pressure, displacement and gas concentration.

4. Drive Execution Unit

Variable frequency motors, servo drivers, hydraulic solenoid valves, pneumatic valves, thyristor power regulators, cooling water pumps / fans and combustion controllers receive instructions from PLC to complete speed regulation, temperature adjustment, cooling flow regulation and atmosphere switching.

5. Communication and Expansion Unit

Industrial Ethernet and field bus modules can connect with upper SCADA monitoring systems and MES production management systems to realize remote monitoring, production data upload and batch process distribution.

6. Safety Interlock Hardware

Sound and light alarms, explosion-proof valves, emergency stop buttons, furnace door interlock switches, over-temperature cut-off devices and combustible gas leakage detection modules.

3. Core Software Functions of the System

1. Multi-segment programmable temperature control curves

Supports more than 30 segments of heating, soaking and cooling programs to automatically match heat treatment processes for different steel grades and workpiece specifications. Closed-loop PID precise temperature control achieves control accuracy of ±1~±5℃.

2. Sequence linkage control of all equipment on the line

Automatically coordinates the time sequence of the whole process including loading, conveying, heating, atmosphere supply, cooling and unloading. For continuous production lines, roller speed is automatically matched with cooling cycle; for batch furnaces, automatic circulation of charging → heating → soaking → cooling → unloading is realized.

3. Independent intelligent regulation of cooling system

Automatically adjusts the frequency of cooling water pumps, spray pressure and fan rotating speed according to workpiece discharge temperature; real-time monitoring of quenchant temperature and concentration triggers automatic heat exchange, liquid replenishment and filtration procedures.

4. Intelligent atmosphere regulation

Automatically adjusts the flow rate of nitrogen, hydrogen and propane based on feedback from oxygen probes and carbon potential detectors to maintain stable protective atmosphere inside the furnace and achieve oxidation-free bright heat treatment.

5. Automatic fault diagnosis and interlock protection

Automatic alarm and safety interlock actions (gas cut-off, power cut-off, shutdown and pressure relief) will be triggered under abnormal conditions such as over-temperature, flame failure, insufficient cooling medium liquid level, gas leakage, conveying overload and fan malfunction, with fault codes recorded for maintenance.

6. Data storage and process traceability

Automatically stores temperature curves, cooling parameters, production time and equipment operation records of each batch of workpieces with a storage period of no less than 1 year. Reports can be exported to meet quality inspection traceability requirements.

7. Dual mode switching: Manual / Automatic

Fully automatic unattended operation; switch to manual mode to control each mechanism individually during commissioning and maintenance.

4. Core Advantages of Automatic Control System

1. High process consistency: Closed-loop automatic control of full-process parameters eliminates manual operation errors and stabilizes mechanical properties of workpieces in each batch.

2. Labor cost reduction: Only one on-duty operator is required for a single production line, supporting 24-hour unattended continuous production.

3. Energy saving and consumption reduction: Heating power, cooling fan and pump load are automatically adjusted according to real-time working conditions to reduce no-load energy consumption.

4. Safe and controllable: Multi-level complete safety interlocks prevent safety accidents such as over-temperature, gas leakage and workpiece collision.

5. Digital expansion: Compatible with factory MES and energy management systems to realize unified management and control of intelligent workshops.

5. Applicable Furnace Types

Roller hearth furnaces, Pusher Furnaces, Bogie Hearth Furnaces, bell-type furnaces, mesh belt furnaces, vacuum furnaces, walking beam quenching & tempering production lines and industrial Cleaning Furnaces.