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The development direction of mesh belt furnace:
The mesh belt furnace production line adopts pollution-free DX gas tempering blackening technology and pollution-free tempering waste heat blackening technology to replace the traditional polluting blackening process. The mesh belt furnace has zero thermal pollution.
Mesh belt furnace detailed introduction:
After more than half a century of development, the first generation of mesh belt furnaces gradually developed from heating in an oxidizing atmosphere to the second generation of heating in a protective atmosphere and less oxidizing atmosphere, and then to the third generation of controlled atmosphere heating and the fourth generation of computer management. How has the mesh belt furnace developed in the 21st century? What are the characteristics of the mesh belt furnace?
Today, the driving force for the development of heat treatment mesh belt furnaces, like other products, comes from market demand, and the results of development come from technological progress. my country's reform and opening-up policy is greatly promoting and accelerating the development of the heat treatment industry.
The mesh belt furnace technology in the 21st century will have distinct characteristics of the times, with four major features: intelligent heat treatment, high-quality heat treatment, low-cost heat treatment, and clean heat treatment.
1.1 Intelligent heat treatment research and development personnel use the latest CAD programs and heat treatment databases, computer simulation technology and control technology, and adopt highly flexible and intelligent comprehensive control and management systems for mesh belt furnaces and their production lines.
In the future, mesh belt furnace operators will only need to input the number of workpieces to be processed and drawings into the computer, and the entire equipment will automatically process high-quality products.
At present, the whole system has realized real-time multi-project operation control. Such as controlling the charging thickness, mesh belt speed, temperature, carbon potential, etc. It can monitor and control the movement of batch feeding on the full screen. It can fully control the process program and store 9999 processes. It can fully record the process parameters (part number, material, temperature, carbon potential, etc.) detected during the operation of the equipment and send them to the computer for processing and storage. It can be retrieved and printed at any time. It can store records for ten years. Password hierarchical control, complete stratification. It contains the new furnace heating program and the furnace shutdown heating program, which can effectively execute the heating process, etc.
1.2 High-quality heat treatment has zero mass dispersion and zero heat treatment distortion. Quality control measures:
Feeding control system: weight, quantity, and uniformity are controllable. Tipping bucket, suction cup, magnetic tape, step, and vibration feeding systems are widely adopted. Feeding rhythm is automatically controlled and frequency conversion is used for speed regulation. Parts are automatically arranged in direction. Feeding thickness is monitored in real time. Guarantee the accurate execution of heat treatment process from the source.
Equipment temperature control: furnace temperature stability ±1°C, furnace temperature uniformity ±10°C, cold treatment temperature uniformity ±5°C, switch-type temperature control will be eliminated.
Atmosphere control in the furnace: The uniformity of the atmosphere in the furnace is controlled by 0.05% oxygen probe, carbon removal air pump, carbon potential controller, and furnace gas regulator, which are reliably matched on the mesh belt furnace. Suitable for nitrogen methanol atmosphere. Methanol acetone (toluene) atmosphere, endothermic atmosphere, exothermic atmosphere, etc. The development of multi-carbon potential control technology combined with oxygen probe and infrared instrument and the emergence of other new carbon potential control technologies can not only improve the accuracy and stability of carbon potential control, but also better adapt to the atmosphere prepared by various gas sources. The dual oxygen probe two-zone carbon potential control technology further optimizes the control of the quality of carburizing and carbonitriding layers. The emergence of the continuous mesh belt furnace water agent quenching and water vapor elimination device stabilizes the atmosphere in the furnace and ensures the accuracy of carbon potential control. The new development of methanol gasification and cracking technology and the widespread use of stirring fans in the furnace have further improved the uniformity of the atmosphere in the furnace. The furnace shell sealing welding method not only saves energy but also is conducive to the long-term stability of the atmosphere in the furnace.
Quenching tank control: In order to ensure the uniformity of workpiece hardness and reduce part deformation, the company has developed from simply reducing the cooling speed to focusing on improving cooling uniformity. The quenching tank has added a powerful agitator with adjustable speed, and has paid attention to the flow field of the quenching tank and the uniformity of the quenching tank temperature. The quenching tank temperature is controllable. The computer cooling medium performance tester has also been accepted by many users.
Heat treatment distortion control; use the quenching furnace hot zone extension to remove stress. Use a fully enclosed heat-insulated controllable graded quenching oil tank. The quenching medium temperature uniformity is 5°C. The quenching tank and the elevator drop system are designed to prevent bumps and scratches. In order to reduce the amount of residual austenite in bearing parts and control the slight deformation of bearings after processing, adding a cold treatment device after quenching in the mesh belt furnace production line will be popularized.
1.3 Low-cost heat treatment In the 21st century, as my country joins WTO, Chinese enterprises will be in the environment of international market competition, and the market will be more in need of inexpensive and high-quality heat treatment equipment. Inexpensive and high-quality heat treatment equipment will be low-cost heat treatment equipment rather than low-price heat treatment equipment. The cost of heat treatment equipment consists of five parts: equipment procurement cost, equipment operation cost, equipment maintenance cost, equipment 4T labor cost, and heat treatment failure treatment cost.
Usually, the equipment procurement cost only accounts for 5-10% of the total equipment cost. Therefore, equipment manufacturers will not strive to provide low-priced heat treatment equipment, but strive to provide low-cost heat treatment equipment.
For this reason, mesh belt furnaces designed and manufactured according to RMs (reliability, maintainability, supportability) engineering theory are very popular.
Furnace type selection: The design starts with the selection of the furnace type with or without muffle.
Heat-resistant steel material selection: high-quality Fe-Cr-Ni, Fe-Ni-Cr, Ni-based alloy materials are selected reasonably according to the furnace's operating temperature range, heat treatment process, etc., so that the actual life extension and performance-price ratio tend to be more reasonable. The life of the muffle can reach 2-5 years, the mesh belt 2-4 years, the roller 5-10 years, the radiation tube 2-4 years, and the fan 5-10 years.
Instrument and electrical material selection: High-reliability PLC programmable controllers, SRC heating modules, adaptive digital temperature controllers, and carbon controllers are commonly used to achieve trouble-free operation throughout the life cycle of the equipment.
Sensing element selection: atmosphere control oxygen probe life 1 year, carbon potential control accuracy ±0.05%, thermocouple life more than 5 years, control accuracy ±0.05%
Refractory material selection: 0.48 ultra-light anti-carburization bricks, ultra-light insulation boards, and refractory wool with a service life of 5 years.
Common defect prevention devices: prevent parts from knocking and scratching the cushion; prevent parts from jumping out of the baffle; prevent parts from jumping out of the torque limiter that damages the transmission mechanism; prevent parts from sticking and spraying and brushing devices: prevent parts from sticking and groove-type lifting; prevent parts from pitting and the washing liquid is difficult to drain. Mountain-type and drum-type drying devices. Enlarge and lengthen the tempering furnace to ensure high hardness uniformity, etc.
(2) Maintainability: The fault point is automatically displayed; the upstream channel of the fault point automatically shuts down after a fault occurs; automatic sound and light alarms are given; and special maintenance tools are provided.
(3) Security: Serving users wholeheartedly and considering users in every aspect are no longer empty words. More and more manufacturers publicly promise to quickly assist buyers to solve problems when they receive calls for help from buyers: if problems cannot be solved over the phone, they will be sent immediately. The seller sets up a spare parts library for buyers. The seller establishes a reporting system for spare parts required by buyers. With the development of emerging network technologies, remote control has become a reality. The cooperation between suppliers and users will be more tacit, and the application of new processes and new technologies will drive costs down further.
(4) Energy conservation: The “15th Five-Year Plan” for heat treatment requires that the average power consumption of heat treatment plants in major industrial cities across the country be reduced to below 500 KWh/t. The energy utilization rate of mesh belt furnaces will be increased to 360-420 KWh/t (including quenching, cleaning and tempering).
Heat exchanger technology, waste heat utilization technology, furnace shell airtight welding technology, and energy-saving technology that reduces the surface area of the furnace body (such as cylindrical type) are widely used. 0.48 ultra-light anti-carburization bricks, ultra-light insulation bricks, ultra-light insulation boards, and refractory wool furnace construction technology are used to increase the furnace wall temperature by 6°C. Rapid cooling technology for tempering furnaces is used. High-pressure fan oil blowing and oil saving technology is used. The use of direct-generation atmosphere using air plus propane can save 80% of the atmosphere cost. With the realization of the domestic West-East Gas Transmission Project, the mesh belt furnace that directly uses primary energy natural gas will be expanded, which will bring significant overall energy-saving effects. The promotion and application of equipment and process energy-saving technology will shorten the heat treatment process cycle, such as zero-insulation heat treatment of carbon steel: thin-layer carburizing (carbonitriding) direct quenching omitting tempering: double oxygen probe two-zone carbon potential control shortens the carburizing and carbonitriding time and other processes will be expanded.
1.4 Clean heat treatment
In 1992, the World Summit on Environment and Development adopted the "Ganshi Century Agenda" to advocate the development of clean production. In 1995, my country officially listed clean production as a common technology for key development and promotion in the "Decision to Accelerate Scientific Progress". Further promote and develop various clean heat treatment technologies and cleaning and cleaning technologies. During the "15th Five-Year Plan" period, the discharge of various wastewater, waste gas and waste residue must meet the relevant national standards. In 2015, we will strive to achieve zero environmental pollution caused by heat treatment production. Ganshi Century's mesh belt furnace reduces the impact on the environment to zero during the production process. More water-based quenching media are used to gradually replace quenching oil. Quenching oil realizes online closed-loop control, and adopts advanced oil-water separation technology and oil purification technology (the separation effect of the oil-water separator can be less than 10 PPM. The centrifugal oil cleaner can remove 1Lt of impurities in the oil). The recovery rate of electrostatic recovery technology for oil fume pollution can reach 0.999. The clean combustion degreasing method is implemented by extending the hot zone length of the quenching mesh belt furnace.
The mesh belt furnace production line adopts pollution-free DX gas tempering blackening technology and pollution-free tempering waste heat blackening technology to replace the traditional polluting blackening process. The mesh belt furnace has zero thermal pollution.
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