产品概述
U 型辐射管是热处理工业炉主流间接加热装置，又称双通道辐射管。燃烧器与排烟口同侧布置于炉墙一端，烟气沿管道前行，经末端 U 型弯头折返回流，依靠管壁红外辐射向炉膛输送热量。
辐射管隔绝火焰、燃烧烟气与工件，保护炉内可控气氛，避免工件氧化、脱碳，广泛应用于各类燃气热处理炉，是连续退火炉、箱式渗碳炉、台车炉标配加热元件。
工作原理
燃气在辐射管内部充分燃烧，高温烟气沿第一通道抵达炉体深处，通过 180°U 型弯折返，沿平行支管回流排出。回流高温烟气可预热进气，提升热能利用率；相比直管辐射管，有效缩小管道轴向温差，炉膛温度分布更加均衡。
热量通过金属管壁以热辐射方式传递至工件，炉内工艺气氛与燃烧系统完全隔离，保障热处理工艺稳定。
核心优势
1.安装维护便捷
The burner and exhaust ends are concentrated on the same furnace wall, eliminating the need for openings on both sides and resulting in superior furnace sealing; maintenance and replacement of radiant tubes can be performed without entering the furnace chamber, significantly reducing downtime.
2.Excellent temperature uniformity
The dual-channel, U-turn structure mitigates unidirectional temperature gradients, reduces the temperature differential between the furnace’s high- and low-temperature zones, effectively eliminates heating dead spots, and ensures consistent heat treatment quality across batches of workpieces.
3.Higher thermal efficiency
The recirculating flue gas undergoes continuous heat exchange, fully recovering waste heat; under identical operating conditions, energy consumption is superior to that of traditional straight radiant tubes.
4.Suitable for various atmospheric conditions
Constructed from heat-resistant alloy, the material offers excellent resistance to oxidation, carburization, and sulfur corrosion, making it suitable for complex furnace environments involving nitrogen, endothermic atmospheres, and protective atmospheres.
5.Flexible structure; supports non-standard customization
Pipe diameter, total length, bending radius, and flange connections can all be customized to suit various furnace layouts, including batch furnaces, continuous mesh-belt furnaces, and roller-hearth furnaces.
Selection of Mainstream Materials and Applicable Operating Conditions
Material solutions can be tailored based on the customer’s operating temperature, furnace atmosphere, and start-stop frequency.
1.ZG40Cr25Ni20Si2 (HK alloy)
Long-term operating temperature: ≤1150°C
Features: Manufactured via centrifugal casting, resulting in a dense microstructure; offers creep and carburization resistance. Suitable for carburizing and annealing furnaces; a widely used, mainstream material in the market.
2.310S (0Cr25Ni20) Weldable Grade
Long-term operating temperature: ≤1050°C
Features: Short processing cycle, high cost-performance ratio; suitable for medium-to-low temperature tempering furnaces and bright annealing furnaces.
3.ZG45Ni48Cr28W5Si2
Long-term operating temperature: ≤1250°C
Features: High nickel-chromium alloy offering resistance to high-temperature corrosion and thermal shock; the preferred choice for demanding high-temperature operating conditions involving frequent start-stop cycles.
4.FeCrAl alloy
Suitable for oxidizing atmospheres at medium-to-high temperatures; offers outstanding oxidation resistance and significant cost advantages.
Typical application areas
- Steel Industry: Continuous annealing furnaces for steel strips, hot-dip galvanizing lines, and solution treatment furnaces for steel plates.
- Mechanical Heat Treatment: Gear carburizing furnaces, bogie-hearth quenching furnaces, bearing tempering furnaces, and box-type controlled-atmosphere furnaces.
- Metallurgical Sintering: Powder metallurgy sintering furnaces, ceramic roller kilns
- Non-ferrous metals: Bright heat treatment furnaces for aluminum and copper materials
Key Technical Parameters (Non-standard specifications supported)
- Common outer diameters: Φ80mm–Φ250mm
- Pipe wall thickness: 6–12 mm (cast); 3–6 mm (welded)
- Effective length per unit: ≤4000 mm
- Permissible operating temperature: 800°C–1250°C
- Connection types: Flanged connection or direct plug-in; compatible with various domestic and international burners.
Our Custom Services
1.Provide material selection proposals based on furnace dimensions, furnace chamber temperature, and atmospheric conditions;
2.Customizable U-bend radius, total length, flange dimensions, and mounting brackets;
3.The surface can be coated with a high-temperature radiative coating to enhance radiative heat transfer efficiency;
4.One-stop supply of matching radiant tube supports and sealing assemblies;
5.Direct factory production; supports manufacturing based on drawings and sample prototyping; factory-conducted flaw detection testing is available.
结语
For heat treatment production lines aiming for process stability and reduced operation and maintenance costs, U-shaped radiant tubes have become the preferred heating solution for many furnace manufacturers, thanks to their ease of installation, balanced temperature control, and high reliability.
Whether you are upgrading an existing furnace or building a new heat treatment production line, please provide parameters such as furnace temperature, atmosphere, and chamber dimensions, and we will match you with the most suitable U-shaped radiant tube solution.
