{"id":5576,"date":"2026-08-03T06:38:41","date_gmt":"2026-08-03T06:38:41","guid":{"rendered":"https:\/\/kilnroller.com\/?p=5576"},"modified":"2026-08-03T06:38:45","modified_gmt":"2026-08-03T06:38:45","slug":"u-shaped-radiant-tube-core-component-for-indirect-heating-in-industrial-furnaces","status":"publish","type":"post","link":"https:\/\/kilnroller.com\/ru\/u-shaped-radiant-tube-core-component-for-indirect-heating-in-industrial-furnaces\/","title":{"rendered":"U-Shaped Radiant Tube | Core Component for Indirect Heating in Industrial Furnaces"},"content":{"rendered":"<h2 class=\"wp-block-heading\">Product Overview<\/h2>\n\n\n\n<p>The U-shaped radiant tube\u2014also known as a dual-pass radiant tube\u2014is a mainstream indirect heating device for industrial heat treatment furnaces. The burner and exhaust outlet are positioned on the same side of the furnace wall; flue gas travels along the tube, reverses direction at the U-shaped bend at the far end, and transfers heat to the furnace chamber via infrared radiation from the tube walls.<\/p>\n\n\n\n<p>Radiant tubes isolate the workpiece from flames and combustion flue gases, thereby protecting the furnace&#8217;s controlled atmosphere and preventing workpiece oxidation and decarburization. Widely used in various gas-fired heat treatment furnaces, they serve as standard heating elements for continuous annealing furnaces, box-type carburizing furnaces, and car-bottom furnaces.<\/p>\n\n\n\n<p><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-1024x768.jpg\" alt=\"\" class=\"wp-image-5577\" style=\"width:384px;height:auto\" srcset=\"https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-1024x768.jpg 1024w, https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-300x225.jpg 300w, https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-768x576.jpg 768w, https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-1536x1152.jpg 1536w, https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-2048x1536.jpg 2048w, https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-16x12.jpg 16w, https:\/\/kilnroller.com\/wp-content\/uploads\/2026\/08\/206cff9328559eedd57a06ef01c49943-600x450.jpg 600w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Working Principle<\/h2>\n\n\n\n<p>The gas undergoes complete combustion inside the radiant tube; high-temperature flue gas travels through the first passage to the depths of the furnace, reverses direction via a 180\u00b0 U-bend, and flows back out through a parallel branch pipe. This recirculating high-temperature flue gas preheats the incoming air, thereby enhancing thermal efficiency; compared to straight radiant tubes, this design effectively reduces the axial temperature gradient along the tube, resulting in a more uniform furnace temperature distribution.<\/p>\n\n\n\n<p>Heat is transferred to the workpiece via thermal radiation through the metal tube walls; the process atmosphere inside the furnace is completely isolated from the combustion system, ensuring the stability of the heat treatment process.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Core Advantages<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1.Easy to install and maintain<\/h3>\n\n\n\n<p>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.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2.Excellent temperature uniformity<\/h3>\n\n\n\n<p>The dual-channel, U-turn structure mitigates unidirectional temperature gradients, reduces the temperature differential between the furnace&#8217;s high- and low-temperature zones, effectively eliminates heating dead spots, and ensures consistent heat treatment quality across batches of workpieces.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3.Higher thermal efficiency<\/h3>\n\n\n\n<p>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.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4.Suitable for various atmospheric conditions<\/h3>\n\n\n\n<p>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.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5.Flexible structure; supports non-standard customization<\/h3>\n\n\n\n<p>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.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Selection of Mainstream Materials and Applicable Operating Conditions<\/h2>\n\n\n\n<p>Material solutions can be tailored based on the customer&#8217;s operating temperature, furnace atmosphere, and start-stop frequency.<\/p>\n\n\n\n<p><strong>1.ZG40Cr25Ni20Si2 (HK alloy)<\/strong><\/p>\n\n\n\n<p>Long-term operating temperature: \u22641150\u00b0C<\/p>\n\n\n\n<p>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.<\/p>\n\n\n\n<p><strong>2.310S (0Cr25Ni20) Weldable Grade<\/strong><\/p>\n\n\n\n<p>Long-term operating temperature: \u22641050\u00b0C<\/p>\n\n\n\n<p>Features: Short processing cycle, high cost-performance ratio; suitable for medium-to-low temperature tempering furnaces and bright annealing furnaces.<\/p>\n\n\n\n<p><strong>3.ZG45Ni48Cr28W5Si2<\/strong><\/p>\n\n\n\n<p>Long-term operating temperature: \u22641250\u00b0C<\/p>\n\n\n\n<p>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.<\/p>\n\n\n\n<p><strong>4.FeCrAl alloy<\/strong><\/p>\n\n\n\n<p>Suitable for oxidizing atmospheres at medium-to-high temperatures; offers outstanding oxidation resistance and significant cost advantages.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Typical application areas<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Steel Industry: Continuous annealing furnaces for steel strips, hot-dip galvanizing lines, and solution treatment furnaces for steel plates.<\/li>\n\n\n\n<li>Mechanical Heat Treatment: Gear carburizing furnaces, bogie-hearth quenching furnaces, bearing tempering furnaces, and box-type controlled-atmosphere furnaces.<\/li>\n\n\n\n<li>Metallurgical Sintering: Powder metallurgy sintering furnaces, ceramic roller kilns<\/li>\n\n\n\n<li>Non-ferrous metals: Bright heat treatment furnaces for aluminum and copper materials<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Key Technical Parameters (Non-standard specifications supported)<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Common outer diameters: \u03a680mm\u2013\u03a6250mm<\/li>\n\n\n\n<li>Pipe wall thickness: 6\u201312 mm (cast); 3\u20136 mm (welded)<\/li>\n\n\n\n<li>Effective length per unit: \u22644000 mm<\/li>\n\n\n\n<li>Permissible operating temperature: 800\u00b0C\u20131250\u00b0C<\/li>\n\n\n\n<li>Connection types: Flanged connection or direct plug-in; compatible with various domestic and international burners.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Our Custom Services<\/h2>\n\n\n\n<p>1.Provide material selection proposals based on furnace dimensions, furnace chamber temperature, and atmospheric conditions;<\/p>\n\n\n\n<p>2.Customizable U-bend radius, total length, flange dimensions, and mounting brackets;<\/p>\n\n\n\n<p>3.The surface can be coated with a high-temperature radiative coating to enhance radiative heat transfer efficiency;<\/p>\n\n\n\n<p>4.One-stop supply of matching radiant tube supports and sealing assemblies;<\/p>\n\n\n\n<p>5.Direct factory production; supports manufacturing based on drawings and sample prototyping; factory-conducted flaw detection testing is available.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p>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.<\/p>\n\n\n\n<p>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.<\/p>\n\n    <div class=\"xs_social_share_widget xs_share_url after_content \t\tmain_content  wslu-style-1 wslu-share-box-shaped wslu-fill-colored wslu-none wslu-share-horizontal wslu-theme-font-no wslu-main_content\">\n\n\t\t\n        <ul>\n\t\t\t        <\/ul>\n    <\/div>","protected":false},"excerpt":{"rendered":"<p>Product Overview The U-shaped radiant tube\u2014also known as a dual-pass radiant tube\u2014is a mainstream indirect heating device for industrial heat treatment furnaces. The burner and exhaust outlet are positioned on the same side of the furnace wall; flue gas travels along the tube, reverses direction at the U-shaped bend at<\/p>","protected":false},"author":1,"featured_media":5577,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[50,49],"tags":[28,51,53,64],"class_list":["post-5576","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-galvanized","category-metallurgy","tag-factory","tag-galvanized","tag-radiant-tube","tag-u-type-radiant-tube"],"_links":{"self":[{"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/posts\/5576","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/comments?post=5576"}],"version-history":[{"count":1,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/posts\/5576\/revisions"}],"predecessor-version":[{"id":5578,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/posts\/5576\/revisions\/5578"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/media\/5577"}],"wp:attachment":[{"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/media?parent=5576"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/categories?post=5576"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kilnroller.com\/ru\/wp-json\/wp\/v2\/tags?post=5576"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}