Jiangsu Aopuda Furnace Equipment Co., Ltd. Cases

According to national standards, industrial resistance furnaces are classified into medium-temperature resistance furnaces, high-temperature box-type electric furnaces with metal heating elements, and high-temperature box-type electric furnaces with silicon carbide heating elements. For small resistance furnaces with a furnace length of no more than one meter, there is a uniform power distribution on the side walls and the bottom of the furnace. For large resistance furnaces, the power will be appropriately increased in areas with large heat dissipation, while the power will be appropriately reduced in areas with small heat dissipation. When heating the furnace charge, it must be in the air medium. Since there is no mechanized device for discharging, only small batches of workpieces can be used for normalizing, annealing and other heat treatments. The power distribution of box-type resistance furnaces is widely used in the industrial field. When distributing the power of the resistance furnace, it will be specifically analyzed according to the size of the resistance furnace. Just like this type of resistance furnace is divided into large and small, the power has different distribution methods for different resistance furnaces when distributing.

Because the electrode lifting mechanism did not reach the position, the secondary load was heavy when the power was supplied, the two-phase overcurrent tripped, and the light gas alarm was sounded at the same time. After the gas was discharged, the gas was ignited and flammable, and then the power was tested and it ran normally. The collapse of materials in the box-type electric furnace and the physical reaction mechanism in the furnace are easy to cause the secondary current to increase, and even the secondary side electrode short circuit and other phenomena, which have a great impact on the electric furnace transformer. The electric furnace transformer is an electrical equipment operating under harsh working conditions. There was a 12.5MVA ore-fired furnace producing silicon manganese products. Suddenly, two light gas alarm signals occurred, and the alarms generated by the two light gas were highly valued. The first light gas alarm signal was when the furnace was operating normally. Due to the physical and chemical reaction in the furnace, the secondary current increased. The rated current was 206.2A. At that time, it was running at 260A (the industry allows overload operation of 20-30%). The light gas alarm signal appeared. After the power outage, the gas was discharged and the power was supplied normally, and no abnormality was found. However, the second time, the light gas signal is when the furnace is powered on during shift change. The electric furnace transformer is one of the important components of ferroalloy equipment. The operating characteristics of the box-type furnace transformer are: frequent power outages, 24-hour operation, and electrode discharge after the furnace is taken out of the furnace, about 8-12 times. In addition, due to the characteristics of the smelting process, the load fluctuates greatly.

Performance analysis of low temperature deformation heat treatment: Recrystallization can occur. Substructure strengthening in low temperature deformation strengthening state, high strength; defect density increases, affecting the precipitation process Low temperature deformation heat treatment process Tube furnace: Typical process (cold deformation, various forms, depending on alloy and performance requirements) Special process (warm deformation-dynamic recovery, improve the stability of the organization after deformation heat treatment). Cold deformation before electric furnace aging High tensile strength and yield strength, but low plasticity Low temperature deformation heat treatment organization analysis: Cold deformation introduces dislocations, improves energy storage, and during low temperature aging, the matrix recovers and subgrains appear; (For alloys that have not been cold deformed, the grains are still quenched grains-it is possible to retain recrystallization) Dispersed particles may be dispersed, and the polygonization of the box furnace is affected by the precipitation particles.

With the development of emerging science and technology, various high-performance requirements have been put forward for materials, so that they can be applied to cutting-edge technologies such as computers, communications, lasers, aviation, aerospace, nuclear energy and national defense science; new materials have superior properties such as high temperature resistance, wear resistance, corrosion resistance and high strength, and have shown broad development prospects. The research and production of these materials and performance testing need to be carried out at high temperatures, and the temperature, pressure, atmosphere, temperature field and other process conditions are very strict. The design and development of new high-efficiency thermal equipment and the research on high-temperature generation technology largely determine the further development of materials. The design, construction and commissioning of heat sources used to manufacture high-temperature materials require the same amount of labor and cost as the research and development of new materials. For many materials and products, in addition to atmospheric pressure and vacuum sintering, the application and continuous progress of hot pressing sintering, atmosphere pressure sintering and hot isostatic pressing technology have accelerated the development of industrial electric furnaces. It makes the development of new industrial electric furnaces more difficult and more advanced. Compared with flame kilns, electric furnaces have many advantages: 1. High thermal efficiency. The heating furnace does not need to burn flue gas as a heat transfer medium, there is no heat loss caused by exhaust gas, the space heat intensity is high, and it can reach a very high temperature.2. Good product quality. The atmosphere in the furnace is clean, the furnace temperature can be controlled, the temperature field is uniform and stable, and it can meet the requirements of various firing systems.3. It can be fired in various artificial atmospheres. For example, products can be fired in N2, Ar, H2, O2 and other atmospheres.4. Simple equipment. Small footprint, saving equipment investment.5. Easy to operate. Good working conditions. However, the auxiliary equipment of the electric furnace is relatively complex, and the installation cost and electricity cost are high. Industrial electric furnace is a comprehensive application technology. It requires designers and researchers to have a solid theoretical foundation in heat transfer, gas mechanics, mechanics, electrical engineering, microelectronics and materials science. They should also have rich production practice experience and professional knowledge related to processing and manufacturing. Modern industrial electric furnaces are highly mechanized and automated, and are computer controlled and managed. Industrial electric furnaces are facing comprehensive technological innovations. They need to transform existing industrial electric furnaces, design and develop new energy-saving and multi-purpose electric furnaces, study key furnace components, continuously improve their technical performance, form specialized production, digest and introduce advanced technologies, and improve the overall design and manufacturing level of my country's electric furnace industry.

A solid bottom furnace is a type of furnace in which the billet is heated on a solid bottom. All the heat required by the billet is supplied by the upper part. Since only one side is heated, this type of furnace is usually only used for heating small-section billets and round tube billets, and the production is low, and usually one-stage or two-stage heating is used. Since there is no bottom water pipe, the insulation is better, so this type of furnace still has a future in energy saving through reform. The two-stage furnace is divided into a preheating section and a heating section along the length of the furnace. The function of the preheating section is to use the high-temperature flue gas from the heating section to preheat the billet to save feed. The two-stage furnace is generally suitable for heating small-section billets. The billet has almost no equalizing time in the furnace and is always in the heating stage. The temperature gradually decreases along the length of the furnace. Since there is no equalizing section, the temperature difference between the inside and outside is large when heating large-section billets. In terms of furnace structure, there is no obvious boundary between the furnace waist and the furnace head of this furnace at the height of the furnace top. The temperature distribution of the three-stage furnace is different from that of the two-stage furnace. The temperature of the heating section rises, and the billet heats faster in this section. The temperature difference on the cross section is also larger. The billet must be heated in the equalizing section before it can be discharged. The billet is heated slowly in the equalizing section, or the surface temperature of the billet is maintained unchanged to increase the internal temperature of the billet. Since the billet does not absorb a lot of heat in the equalizing section, the furnace temperature is slightly lower than that in the heating section. Obviously, the three-stage furnace has higher output and better heating quality than the two-stage furnace, and is suitable for heating thicker billets. Compared with the two-stage furnace, the heating section and the equalizing section of this type of furnace have obvious boundaries in terms of furnace structure. In terms of burner configuration, the waist furnace provides more heat and the head furnace provides less.

1. Two-stage and three-stage heating furnaces. This type of furnace is currently widely used in medium and small steel rolling workshops. There are two ways to discharge this heating furnace. The billet slides onto the roller along the discharge slope at the discharge end. In the side discharge method, the steel is pushed onto the discharge trough and is pushed out of the guard from the side by the steel discharging machine. The advantage of end discharge is that the discharge is convenient and is not limited by the number of furnaces. The disadvantage is that the guard is less tight. The advantage of side discharge is that the furnace is tighter, but it is difficult to discharge more than two heating guards side by side, and it is not easy to handle when the steel is bonded. 2. Multi-stage heating furnace. This type of furnace is suitable for use with large rolling mills with larger production. The guards are relatively long, and the discharge method generally adopts end discharge. At first, the guard was 4-stage, and later it was made into 5-stage, 6-stage and even 8-stage as the output continued to increase. 3. Stepping heating furnace. At present, single-sided heating walking furnace and double-sided heating walking furnace are more commonly used. Single-sided heating furnaces are mostly used to heat thin billets, small billets, round billets and steel pipes that cannot be heated by push-type heating guards. Double-sided heating walking furnaces are generally large furnaces with high output, and are mostly used with strip steel mills with hourly outputs of several hundred tons to more than one thousand tons. 4. Ring heating furnace. This type of furnace is currently widely used for heating billets before perforation in steel pipe workshops, and is also used for heating before rolling wheel rims. In the machinery industry, this type of furnace is also widely used, mostly for heating billets or steel cakes before die forging. 5. Solid bottom heating furnace. This type of furnace is suitable for occasions with small billets and low output. The furnace is generally short, and sometimes the bottom of the furnace has a certain slope to facilitate pushing steel. This type of furnace mostly uses side discharge.

In recent years, fuel prices have tripled compared to 15 to 20 years ago. Foreign countries have conducted extensive research on energy conservation issues, using modern technology to analyze common structures and operating methods in order to obtain updated designs and operating procedures, and to explore and seek new structures and operating methods. The West German Salzgitter Company designed and built two large push-type furnaces with the same capacity. Furnace No. 1 was put into operation in 1971, and Furnace No. 2 was put into operation in early 1976. When designing Furnace No. 2, considering the increase in fuel prices, a higher infrastructure investment was made to reduce fuel consumption in production. The design of the T-type was applied to the mathematical model. A new solution was derived for the differentially expressed heat balance and heat exchange equations. Compared with the conventional method, this method can reduce the computer's calculation program and storage capacity. It can also determine the horizontal temperature gradient caused by the rail (black mark on the rail), heat balance data, and the temperature field of the upper wall, furnace gas and slab of the furnace length. A series of fuel-saving measures were taken in the design of Furnace No. 2. Such as: 1) air preheating to above 6000℃ to improve waste heat recovery rate (air preheating of furnace No. 1 is 4300℃); 2) the wall (especially the furnace top) is well insulated; 3) alloy steel guide baffle burners are used to achieve radiation furnace top micro-firing to improve heat transfer efficiency. The trial production data of furnace No. 2 is completely consistent with the numerical model prediction data. The final temperature was measured to be 12500℃ by a thermocouple inserted into the slab borehole, the temperature difference between the upper and lower surfaces was less than 200℃, and the horizontal temperature difference was not more than 500℃. The fuel consumption of furnace No. 2 is 19% less than that of furnace No. 1, and the heat consumption is saved by 81.5 kcal per kilogram of steel. When the annual output of the two furnaces is 1.543 million tons, furnace No. 2 can save 114,100 million kcal of heat per year. According to the current European fuel price of US$8/million kcal, the fuel cost can be saved by 913,000 yuan per year. The construction cost of the No. 2 furnace was approximately $1.5 million more than that of the No. 1 furnace.