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How are heat-resistant steel castings heat-treated?
Common heat-resistant steels typically require casting under high-temperature conditions, which means they must possess sufficient resistance to oxidation, corrosion, and wear. If the material or quality of the product exhibits segregation, it will be unable to achieve the capabilities just described. During the manufacturing process, not only is it essential to select high-quality materials, but after the product has been formed, heat treatment is absolutely necessary. The heat treatment of heat-resistant cast steel involves several steps—such as cleaning, furnace loading, preheating, heating, and cooling—to ensure that the final product attains the desired properties. In this process, certain operations require particular attention; for example, the preheating and cooling stages for bearing housings in coal mills—the preheating step is especially critical for components that are relatively complex.
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05
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10
2023
Precautions Before and After Using a Car-Type Annealing Furnace
To facilitate the heating of large workpieces, trolley-type furnaces suitable for heating steel ingots and large billets have been developed. For heating long bar-shaped components, well-type furnaces have also been introduced. After the 1920s, various mechanized and automated furnace types emerged, capable of increasing furnace productivity and improving working conditions. As fuel resources were developed and fuel conversion technologies advanced, the fuel used in trolley-type annealing furnaces gradually shifted from solid fuels such as lump coal, coke, and coal powder to gaseous and liquid fuels—including producer gas, city gas, natural gas, diesel, and fuel oil—and specialized combustion equipment tailored to these fuels has been developed. Trolley-type annealing
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04
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13
2023
Instructions for the Well-Type Vacuum Furnace Control System
Instructions for the Well-Type Vacuum Furnace Control System: The well-type vacuum furnace control system employs temperature-controlled thermocouples and the Shanghai Guolong intelligent digital display temperature controller for temperature regulation. The temperature controller can precisely maintain the set temperature and simultaneously displays both the target value and the actual measured value. The temperature control system is also equipped with an overtemperature audible and visual alarm function. For temperature recording, the control system utilizes a Shanghai Dahua long-chart temperature recorder to log the furnace chamber temperature; the thermocouples used are of K-type. The compensation lead wires for furnace chamber temperature measurement are connected from the instrument cabinet to the thermocouples inside the furnace body and are supplied by the vendor. The control execution system adopts a high-power thyristor zero-crossing trigger system, complete with a heat sink and a full air-cooling system. Additionally, it is equipped with a self-…
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03
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10
2023
Introduction to Box-Type Quenching Furnaces and Their Process Flow
The box-type quenching furnace, also known as hard-mold forging or permanent-mold forging, is a method in which molten aluminum alloy is poured into a metal mold to produce castings. In aluminum alloy solution treatment furnaces and box-type quenching furnaces, metal cores are commonly used; however, sand cores or shell cores can also be employed. Compared with die casting, aluminum alloy solution treatment furnaces and metal-mold forgings have a longer service life. 2. Advantages of Forging (1) Advantages: The metal mold cools relatively quickly, resulting in a finer-grained casting microstructure that can be further strengthened through heat treatment. As a result, the mechanical properties of metal-mold castings are approximately 15% higher than those of sand-mold castings. Box-type quenching furnaces ensure stable casting quality, with surface roughness superior to that of sand-mold castings and lower defect rates. Moreover, working conditions are improved, and productivity is enhanced.
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02
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09
2023
Introduction to the Basic Structure and Classification of Box-Type Quenching Furnaces
The box-type quenching furnace is a batch-operated furnace suitable for the heat treatment of bar-shaped and long-axis components. The structure of the box-type quenching furnace consists of a cylindrical, deep-well-shaped furnace body. Workpieces are vertically loaded into the furnace using a dedicated crane for heating. The fuels typically used are gas and oil. When electricity serves as the heat source, the furnace is referred to as a well-type resistance furnace. Box-type quenching furnaces are generally installed below the workshop floor level; however, they can also be located above the floor level or split equally between above and below the floor level. The box-type quenching furnace goes by various names, including forced-convection box-type quenching furnace, natural-convection box-type quenching furnace, and well-type gas carburizing furnace. Box-type quenching furnaces can utilize either gaseous or liquid fuels, or they can be electrically heated.
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01
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10
2023
How can we reduce the heating time for the heat treatment of forged blanks?
The ratio of the durations of the two stages—surface temperature equalization (referred to as “uniform heating”) and core temperature equalization (holding at temperature)—to the total heating time varies depending on the heating temperature. At lower heating temperatures, the proportion of time spent on uniform heating is relatively smaller, while the proportion of time spent on holding at temperature is larger. Thus, the key to shortening the overall heating time lies in reducing the duration of the stage that accounts for the greater proportion of the total heating time. According to the principles of heat transfer, there are several ways to shorten the heating time: 1. Ensure uniform heating: When a workpiece is heated, if the temperature distribution is uneven and the surface heats unevenly, it can lead to an eccentricity in the heating center, effectively increasing the cross-sectional dimensions—for example, by adjusting the dimension to 1.4 times the diameter (D).
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09
2022
Customer Service Hotline
Equipment Service: +86-15923378884 (Mr. Yin)
Processing Services: +86-13648364855 (Mr. Gao)
Jingkou Factory
Phone: +86-023-65180506
Email: yin.youzhi@fengdong.com
Address: No. 5, Jingsheng Road, Jingkou Industrial Park, Shapingba District, Chongqing, China.
Bishan Factory
Phone: +86-13648364855 (Mr. Gao)
Email: gao.xinjie@fengdong.com
Address: No. 219, Donglin Avenue, Biquan Subdistrict, Bishan District, Chongqing, China.
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