Bell bright annealing furnace works

The bell-type bright annealing furnace by the heating hood cover, cooling cover, inside cover, stove, vacuum system and electrical control system. The furnace is mainly for strip and wire coiled bright annealing and tempering high production efficiency, less pollution, easy operation and maintenance and so on.
Work piece placed in a protective atmosphere filled with the protective hood uniform heating and cooling. Strong and protective atmosphere circulating fan can work after annealing to obtain a uniform surface hardness and luster, the vacuum system for protective gas and air replacement, the safe and reliable operation. Hood can be equipped with multiple hearth furnace, continuous operation, and its work processes generally: furnace installed - I vacuum - through protective gas - heating - heat - gas, water combined cooling - vacuum cleaners - deflated - baked - next workflow.
1. Vacuum cleaning system can be completely avoided mixing with air, hydrogen, hydrogen atmosphere for high fully applicable, and with plenty of protective gas than simply reduce the cost of cleaning the muffle furnace, the furnace atmosphere to accelerate the transition time. 2. Temperature uniformity is good, the furnace temperature can be controlled within the workpiece within ± 5 ℃, each part to be treated consistent with good mechanical properties.
3. Fan and stove, stove connection with the inner cover parts used PPM level airtight sealed structure for the safe use of the atmosphere to create the conditions to be treated without removal, adhesion phenomena, and to meet carbon steel, alloy steel, etc. bright annealed material.
4. Use of strong convection blower, vacuum cleaning, gas, water and other new technologies combined cooling, can speed up the process cycle, increase productivity, the main performance indicators have reached the level of similar foreign products.
5. Cooling system with a shunt (axis wind turbine structure) as compared to gas, water cooling can accelerate the combination of cooling the workpiece, to simplify the device structure, reducing construction costs and ease of maintenance.
6. Can automatically complete heating, insulation and other processes, temperature SCR power microcomputer intelligent control, programmable logic controller can be used to achieve full operation of automatic process control and automatic recording.
7. With over-temperature alarm, explosion relief, cooling water pressure loss alarm, emergency gas supply and other safety devices, safety and reliability.

High-temperature box resistance furnace advantages

High-temperature box resistance furnace, crucible resistance furnace used in various industrial and mining enterprises, universities, research units, small pieces of steel hardening, annealing, tempering heating. Carbon heater male used in steel mills, iron foundries, laboratories for carbon and sulfur exposition purposes. Therefore, high-temperature furnace with a temperature control device, control thermocouple temperature measurement instructions conditioning, active saving temperature in the furnace. Analog and digital temperature controller is divided into two kinds. Today's sx series resistance furnace is the product of the old reform and upgrade replacement product, with the first registered domestic chic produced initiative of the instrument response xmt series temperature controller and thermocouple, the temperature of the furnace control cutting accuracy higher and more automation. Another variety of special specifications can be customized large box-type furnace, tube furnace, tempering furnace pit. With programmable computer temperature controller can control the speed, temperature band.
When using high-temperature box resistance furnace, heat treatment equipment to work, we still have to pay attention to the following points:
1 Do not use over the course of the maximum temperature of the resistance furnace.
(2) when the sample taken must be installed to intercept the power to prevent electric shock.
3 loading door closed when the sample taken time should be as short as possible to reduce the furnace life.
4 Suppression of the furnace absorbed any liquid.
5 shall not be stained with water and oil sample into the furnace; shall not be moistened with water and oil clip loaded sample taken to avoid accidentally touching the fire;
6 sample taken when mounted to wear gloves to prevent burns.
7 The specimen should be placed on the furnace center, not misplacing.
8 furnaces and not just touch around the sample.
9 should be completed after intercepting power and water supply.
10 management staff are not allowed to manage, may manipulate the high temperature resistance furnace, should be strictly in accordance with the procedures for execution control equipment.

Sealed box furnace into the furnace technology

1. When everything is ready to pass the inspection before working furnace heating, when the the muffle furnace temperature greater than 750oC, only through endothermic atmosphere, the furnace gas positive pressure, and then lit the fire curtain and front room row of net operating.
2. Until the furnace heated to 930oC, the curtain of fire lit, the part is available into the furnace.
3. Quenching lifting mechanism, is expected out baskets channel, is also quenched, pre-cooling, and drain fixture position of the lifting mechanism and process requirements, generally on the platform below the first material basket quenching oil cooling, the material on the above platforms baskets workpiece pushed into the carburizing furnace heating, close the inner door, the third basket pushed the above platform into the front room, along with the net emission of decontamination preheating, under the platform material basket oil the Lek best baked, the inner door is opened first two baskets, baked quenching, and three baskets into the box furnace carburizing, and so on ad infinitum.
4. If the workpiece quenching, the baked air cooling, the material basket should be placed on the platform, pre-cooling, until the next platform material basket furnace installed, let the platform material basket fell baked.
5. Fire curtain door must seal the inner door seal fire curtain shall ensure that the furnace positive pressure, oil and gas will not be admitted.

Refractory ceramic fiber performance and development prospects

In recent years, high-temperature ceramic fiber kiln firing the application prospect of expanding to all kinds of ceramic fiber insulation products to good effect, easy to use, especially in small storage and other features, widely used in all kinds of kilns , which greatly shows high energy efficiency.
(A) variety and performance: ceramic refractory fibers most important indicator is the fiber diameter and thermal stability. Commonly used in ceramic industry is Al2O3SiO2 fiber, according to the level of Al2O3 content into different scope of use, but also to introduce them to improve their Cr2O3 refractory material with antioxidant properties. Generally high alumina content, low content of iron and other impurities fiber product was pure white, chromium oxide fibers were introduced Pins milk yellow color tone. The average diameter of the ceramic fibers of 2-4 microns. Fiber fineness, low density, low thermal conductivity by use of high temperature. If crude fiber, high density use is not ideal. The thermal stability index fiber is more important. Al2O3-SiO2 fiber variety of products at 1260 ℃ linear shrinkage between the range of 35-88%. Also directly affects the amount of shrinkage thermal stability.
Low thermal conductivity of the fiber density, light weight, the design and construction of the furnace are used when lighter steel support structure, so that the development of ceramic kiln into the "kiln lightweight" era. Fiber regenerative small, adapt to rapid heating and cooling firing mode. Flexible fibers can be processed into products with recesses or openings, and has good resistance to mechanical vibration and shocks, good chemical stability, these advantages is the development of a new furnace, and spread to ceramic technology, industry have an important role in promoting development.
Currently ceramic fiber products are: carpets, blankets, blocks, bulk fiber, fiber paper and vacuum forming of various products, the working range is generally 871-1427 ℃, special circumstances may be short-term temperatures above the temperature limit is used.
(2) masonry methods and precautions: refractory fiber felt for furnace lining can greatly improve energy efficiency. General use of synthetic organic binder so that the fiber volume tubular or sheet-shaped fabric. Lightweight high temperature furnace brick masonry wall, the available refractory ceramic fiber blanket paste into the lining, after firing, the fiber mat or plate form a certain rigidity and ability to have satisfactory reply, the cooling time can play back so that the seam taut.
Masonry fibers are usually two ways: First, the rugs applicator layer by layer, and then the bolt lever riveted together, usually in the 1222 ℃ temperature below with metal bolt rod, 1223 ℃ above using ceramic quality rivet. Side by side with the bulk heat resistant fiber and cement filling. Riveting quality ceramic pieces can prevent deposition of carbon fiber deterioration. The second method is the use of prefabricated assembly, which uses rugs stacked preform or the rugs with a wide 305mm folded accordion style preform. In comparison, the latter due to the hot surface next to the furnace shell are the same materials, energy efficient, but the cost is higher.
Temperature, the fiber preform required masonry seam formed elastic fiber inlay. Prefabricated assembly, easy installation, quick and easy maintenance, simply replace the damaged part down.
On the thermal efficiency, the layers of the applicator way better than prefabricated assembly. Because the former fiber direction perpendicular to the heat, the stack assembly of prefabricated shaped fiber direction parallel to the heat flow difference between the two is about 20-40% of the heat conductivity, such as accordion-like assembly of the preform folded in between its fiber direction parallel and perpendicular to the heat flow.
(3) Prospect: Due to rising energy prices, fuel costs will become a bottleneck in the development of ceramics curb, saving even more important. People are increasingly concerned about the heat loss of the furnace, some directly affixed to the original surface layer of refractory lining refractory ceramic fibers in order to improve thermal efficiency. In the kiln must be affixed to the wall before the apparent cracks or spalling parts repaired. But insulating firebrick and refractory fiber can not be indiscriminate. So far, such as basic oxygen steelmaking furnaces, cement rotary kiln lining, serious erosion due to high temperature chemistry are temporarily unavailable fiber as lining.
For continuous heating equipment, such as ceramic tunnel kiln, have long been used as a refractory ceramic fiber lining continuous heating equipment, according to the information reported, quickly push board kiln and tunnel kiln refractory ceramic fibers used in energy-saving effect is very significant. In particular, ultra high temperature heating, such as firing temperature 1538 ℃ -1649 ℃ kiln, the use of the best energy-resistant fiber.
At present, Europe and Japan ceramic kiln equipment used ceramic fiber lining. Gas-fired tunnel kiln recently Japan will be decomposed into sub-sections such as car manufacturing structure, and then delivered to the construction site porcelain factory assembled, all this is due to the use of ceramic fiber material, saving furnace costs, easier sake. Modified from the material aspects of ceramic fiber products to promote energy efficiency study is also underway.

High-pressure atmosphere sintering furnace

A high-pressure atmosphere sintering furnace structure
A high-pressure atmosphere sintering furnace designs and manufactures three types of pressure vessel standards, 16MnR or 304 of the furnace shell.
2 door locking bolts or teeth gnawing quick release flange, easy to operate safe and reliable.
Lid lifting electro-hydraulic operating light to reduce labor intensity.
Furnace insulation materials for carbon deposition the composite hard felt, heating elements for German imports of graphite.
5 temperature measurement devices using the company's own development of ultra-high temperature protective tube with tungsten-rhenium thermocouple, thermocouple wire service life of up to six months.
Control system for PLC + touch screen, complete safety interlock protection and alarm functions.
7 high-pressure valves and piping, etc. selection the "Shiwei Locke brands imported products, safe and reliable.
High-pressure sintering furnace features
1, the pressure is easy security qualified, safe and secure
2, dual high-temperature protection device
3, electric heaters burning air defense protection device
4, the double pressure protection switch
5, mechanical overpressure protection relief switch
6, automatic pressure relief safety shutdown protection switch
7, dual low-voltage door limit protection switch
High-pressure atmosphere sintering furnace electrical control
1, LCD liquid crystal display the HMI controller + PLC program controller
2,40 segment thermostat range memory storage function
3, the program automatically monitor and abnormal exclusion
4, PID + SCR the automatic calculation temperature control interface
5, the temperature and pressure data sampling recorder.

Vacuum heat treatment furnace experiment points to note

1. Vacuum furnace should have a fast-cooling devices. Cooling water pressure should be greater than 0.2Mpa, flow should be adjustable.
2. Heating: Put the workpiece, usually the first pre-heated before pumping to 6.67Pa when heated.
3. Heating process, the workpiece will be deflated and the furnace materials, the vacuum decreased.
4. Cooling gas: steel is generally used 99.995% purity nitrogen, high temperature alloys used 99.999 percent nitrogen or argon, titanium using 99.995% argon.
5. Vacuum furnace part of all active connections rubber O-ring sealed connections, the parts are cooled by water.
6. Vacuum tempering, annealing, solution treatment and vacuum vacuum aging process with conventional heating temperature is generally the same as the heating temperature.
7. Quenching the workpiece under vacuum, vacuum quenching oil should be used, this oil has a low saturated vapor pressure.
8. Vacuum furnace maintenance should state in a vacuum or under nitrogen charge to avoid the usually do not inhale, absorb moisture.
9. Domestic vacuum furnace pressure rise rate should not exceed 1.33Pa / h, some foreign enterprises standard 0.67Pa / h.
10. Titanium alloy vacuum furnace process, not with nitrogen as the cooling gas, because of titanium and nitrogen at high temperatures, to form titanium nitride golden yellow.
11. Vacuum heating mainly by radiation, the workpiece should be maintained in the furnace space.

Advantages of vacuum heat treatment furnace

The vacuum treatment furnace is a device of the workpiece to a heat treatment under vacuum conditions, the vacuum processing and compared to other heat treatment method having the following unique advantages:
Purification action: make a metal surface oxide decomposition, thereby obtaining a bright, clean surface.
2, vacuum protective effect: metal can avoid the adverse effects of oxidation, decarburization, carbon keep the chemical composition and brightness of the original workpiece surface.
Outgassing: original dissolution of the workpiece may be removed in vacuo, the absorption of gas, so that the metal product performance has improved significantly.
4, the degreasing effect: heating in a vacuum, self-volatile cooling agent, a lubricant, such as grease to the metal parts used in the machining and stamping molding process, and is pumped in vacuo, and will not react with the surface of the part at a high temperature. It can be obtained no oxidation, no corrosion very smooth surface.
5, save energy: vacuum heat treatment furnace heat storage and heat loss, high thermal efficiency.
6, the heat treatment of the workpiece deformation is small, easy to crack, product qualification rate, long life; vacuum heat treatment can easily be in strict accordance with technical requirements to control the temperature change, so as to obtain the desired microstructure, reducing the deformation.
7, after the vacuum heat treatment product can be directly used for plating or as a final product, eliminating the step of cleaning, surface machining and other auxiliary greatly reduce production costs.
8, environmental pollution, high degree of automation, simple operation.
Vacuum heat treatment furnace features:
Quenching, tempering, annealing, brazing, sintering, etc. a variety of purposes;
2 fully automated process control, stable operation, human-machine interface (optional);
3 powerful cooling capacity the quench a wider range of applications;
Uniform heating, cooling uniformity, small deformation of the workpiece;
Energy conservation, and pollution;
6 kinds of protection function, make the operation safer;
Cooling Fan Frequency (optional), the cooling method is more flexible.
Vacuum heat treatment furnace uses:
Vacuum heat treatment furnace is widely used in alloy steel, tool steel, high speed steel, tool steel, bearing steel, spring steel, stainless steel, heat-resistant alloys, a variety of magnetic materials, non-ferrous metals heat treatment.

Furnace charging methods and requirements

First, the loading method
EAF is the most common cold loading, their way into the furnace is divided into different manual loading and mechanical loading.
Manual loading and more for a nominal capacity of less than 3t electric furnace, the disadvantage is the loading time is long, low productivity, labor-intensive.
Baskets top loading is the best method of loading speed, heat loss, and the charge can be installed in advance in advance, fabrics and reasonable.
Second, the requirements for loading
To shorten the time to ensure that the recovery rate of alloying elements, reducing power consumption and improving lining life, charging time required: accurate, pretend to be dense fabric reasonable and fast into the furnace.
Before loading, ingredients workers to conscientiously planned furnace, with the requirements of steel ingredients, according to the requirements of different kinds of steel craft, careful analysis and calculation, accurate ingredients. Therefore, the necessary approval required before loading into the steel material with the composition of the alloy composition, but also to check metering equipment to ensure full penetration after suitable chemical composition, weight accurately, in order to facilitate the smooth progress of smelting.
Dense packed charge, can be obtained once entirety, and can improve the conductivity of the charge transfer performance, the electrode wear well, the muffle furnaces arc stability, and is conducive to melt. To achieve a dense, smooth loading time will depend on large, medium and small charge a reasonable match. Typically, the charge is less than 10kg of petit material, 10 ~ 25kg called the material, more than 50kg called aniseed. When charging, the charge capacity of different furnaces have different size requirements, but the charge may not exceed the maximum total weight of the charge 1/50.
Reasonable fabric is more important, generally is part of the small material miscellaneous iron baskets mounted on the bottom, in a small material above the center of the baskets loaded aniseed or refractory material, intermediate fill small material, so smooth, dense, large gaps, making it conducive to conducting, but also to eliminate and prevent the collapse of the bridge material is broken electrode material. The remaining material packed in small aniseed or refractory material on top and around. Finally, in the upper part of baskets loaded material weight 0.02% to 0.03% of the miscellaneous iron, in order to facilitate arc, stable arc current and reduce radiation damage on the lid.
Steel slag, Tang Tao steel and other difficult-conductive charge should be installed in a place away from the electrodes, so as not to affect the conductivity. Do not install in the vicinity of pig iron door, but to be installed in aniseed or refractory material around facilitate its carburizing effect, reducing aniseed or refractory material melting, thus speeding up the melting. Where the alloy into the furnace, in order to ensure the recovery rate of the elements should be based on their different physical and chemical properties installed in different locations, such as tungsten, molybdenum, iron high melting point, easily oxidized, can be installed in the high temperature zone, but do not install in the arc below; ferrochrome, nickel plate, ferromanganese, etc. should be installed in a position away from the high temperature zone, to reduce their volatilization losses.
The furnace temperature is high in the middle, surrounded by low, so the cloth should be done high in the middle, surrounded by low. In addition, you should also ensure Chuanjing fast, do not bypass, after the furnace door and slope without aniseed, no refractory material.

Industrial furnace controlled atmosphere

Controlled atmosphere Principle:
Metal furnace heated in the flame, the main component of the atmosphere surrounding the CO2, CO, H2O, H2, O2 and N2, etc. Including CO2, H2O and O2 to metal oxidation or decarburization; H2 and CO is a reducing gas; N. In addition to the particular metal, in general, is an inert gas, but in general contain a small amount of nitrogen oxide impurities, directly to the heat treatment can also cause oxidation.
Each direction of a reversible reaction, according to their chemical equilibrium constant and the temperature. That is, the furnace gas is an oxidizing or reducing, depending on the temperature of the furnace gas in the ratio of the content of the gas may be. Iron redox shown FIG. For example, at 825 ℃, when the CO and CO2 content and the ratio of H2 and H2O in the ratio greater than 2, the iron is not oxidized, but it is difficult to stabilize combustion control in this state, even if done, when the temperature drop to below 750 ℃, this atmosphere is oxidizing it. Therefore, in general, the flame furnace atmosphere is oxidizing or reducing is not controllable. Therefore, during the heat treatment, a chemical change when allowed, or only allowed to take place there is a change (such as carburization or decarburization etc.), only a radiation tube or muffle furnace electrically heated indirectly heated or modified and pass into the preform, the composition of the controlled atmosphere desirable.
Controlled atmosphere Category:
Controlled atmosphere metallurgical plants commonly used fuel preparation can be divided into the atmosphere, nitrogen-based controlled atmosphere, ammonia preparation of pure hydrogen atmosphere and so on.
Fuel preparation Atmosphere:
General use gas fuel (natural gas, propane, butane, and coke oven gas, etc.) or through incomplete combustion catalytic reaction, removal of CO2 and H2O from the system controlled atmosphere. When the heat released by the combustion process to maintain the reaction proceeds, the resulting gas is called exothermic atmosphere can be divided into Ⅰ, Ⅱ and type Ⅲ type, in order to adapt to different uses; When the excess air coefficient is very low, you must heat to maintain the reaction, the resulting clear endothermic gas atmosphere. Two kinds of combustible gases contained in the atmosphere based on the number, type and concentration can be divided into short type.
Nitrogen-based controlled atmosphere:
Mainly refers to the preparation of industrial nitrogen mixed atmosphere of nitrogen and hydrogen. Preparation exothermic fuel type Ⅱ and Ⅲ type also belong to this atmosphere. General separating oxygen from air or nitrogen pressure swing adsorption proceeds, oxygen is about 0.2% to 2%, only as a general controlled atmosphere diffuse gas; refined by oxygen is less than 10-5 nitrogen, can be used for light less demanding steel protective atmosphere. Should generally be mixed with a small amount of H2 or CH4, by catalytic deoxygenation dry before as a controlled atmosphere.
Preparation ammonia atmosphere:
Is evaporated with anhydrous ammonia through the catalyst interior, external heating to near 1000 ℃ tank reactor, the mixture containing 25% N2 and 75% H2 gas mixture, cooling, drying shall be controlled atmosphere of ammonia decomposition. Add ammonia of incomplete combustion air to remove CO2 and H2O, and then by further purification of the main component is obtained ammonia burner controlled atmosphere of N2.
Purity:
Solution with water or from a coke oven gas, chemical byproduct gas extracted by pressure swing adsorption method.
Controlled atmosphere choice:
Mainly based on the type of material and heat treatment process requirements to choose.

Use a vacuum furnace heat treatment process Precautions

1 titanium alloy vacuum furnace process, not with nitrogen as the cooling gas, because of titanium and nitrogen at high temperatures, to form titanium nitride golden yellow.
2 vacuum furnace part of all active connections rubber O-ring seal connection, this section are cooled by water.
3 work hardening in a vacuum state, a vacuum quenching oil should be used, this oil has a low saturated vapor pressure.
4 vacuum furnace maintenance should fill in a vacuum or nitrogen status, avoid usually do not inhale, absorb moisture.
5 domestic vacuum furnace pressure rise rate should not exceed 1.33Pa / h, some foreign enterprises standard 0.67Pa / h
6 vacuum heating mainly by radiation, the workpiece should be kept in the furnace space.
7 during the heating process, the workpiece will be deflated and the furnace materials, the vacuum decreased.
8 vacuum tempering, annealing, solution treatment and vacuum vacuum aging process with conventional heating temperature is generally the same as the heating temperature.
9 vacuum furnace should have a fast-cooling devices. Cooling water pressure should be greater than 0.2Mpa, flow should be adjustable.
10 Cooling gas: steel is generally used 99.995% purity nitrogen, high temperature alloys used 99.999 percent nitrogen or argon, titanium using 99.995% argon.
11 Heating: Put the workpiece, usually the first pre-heated before pumping to 6.67Pa when heated!