{"id":8395,"date":"2026-09-29T17:41:56","date_gmt":"2026-09-29T15:41:56","guid":{"rendered":"https:\/\/tecratubes.com\/?p=8395"},"modified":"2026-09-29T17:47:16","modified_gmt":"2026-09-29T15:47:16","slug":"heat-exchanger-tubes","status":"publish","type":"post","link":"https:\/\/tecratubes.com\/en\/news\/heat-exchanger-tubes\/","title":{"rendered":"Heat exchanger tubes: applications and materials"},"content":{"rendered":"<p dir=\"ltr\">Heat exchangers are essential components in many industrial sectors, such as <a href=\"https:\/\/tecratubes.com\/en\/fields\/oilgas-en\/\" target=\"_blank\" rel=\"noopener\"><strong>oil &amp; gas<\/strong><\/a>, <a href=\"https:\/\/tecratubes.com\/en\/fields\/petrochemical\/\" target=\"_blank\" rel=\"noopener\"><strong>petrochemical<\/strong><\/a> and <a href=\"https:\/\/tecratubes.com\/en\/fields\/energy\/\" target=\"_blank\" rel=\"noopener\"><strong>energy<\/strong><\/a>. They are part of a system in which thermal energy is exchanged between fluids at different temperatures.<\/p>\n<p dir=\"ltr\">Selecting the most suitable tubes for building heat exchangers is essential, since they must comply with strict standards to ensure <strong>high performance<\/strong>, <strong>thermal conductivity<\/strong>, <strong>durability<\/strong> <strong>over time<\/strong> and <strong>compliance<\/strong> with safety standards.<\/p>\n<p dir=\"ltr\">The tube is the surface through which heat passes from one fluid to the other. It is also the <strong>most stressed<\/strong> component of the entire heat exchanger, because it is exposed to both fluids, to thermal fluctuations, to operating pressure and often to corrosive agents. An unsuitable tube can cause leaks, contamination between the two circuits, loss of efficiency and unplanned plant shutdowns. The cost of these problems far exceeds that of the initial supply.<\/p>\n<h2 dir=\"ltr\"><\/h2>\n<h2 dir=\"ltr\">Types of heat exchangers<\/h2>\n<p dir=\"ltr\">Heat exchangers are used in different industrial contexts and, depending on their intended use, there are <strong>several types<\/strong>:<\/p>\n<ul dir=\"ltr\">\n<li><strong>Shell and tube<\/strong>, consisting of a bundle of tubes enclosed in a cylindrical shell.<\/li>\n<li><strong>Double pipe<\/strong>, characterized by two cylindrical tubes and generally used in small-scale systems.<\/li>\n<li><strong>Spiral<\/strong>, consisting of tubes coiled in a spiral so that fluids flow in two different directions.<\/li>\n<li><strong>Plate<\/strong>, built with thin plates and featuring high thermal efficiency.<\/li>\n<\/ul>\n<h2 dir=\"ltr\"><\/h2>\n<h2 dir=\"ltr\">Requirements for heat exchanger tubes<\/h2>\n<p dir=\"ltr\">Compared to standard process piping, a heat exchanger tube must meet <strong>more specific requirements<\/strong>. It must ensure efficient heat transfer and maintain its integrity and tightness over time, often under demanding operating conditions. The main construction aspects to consider are the following:<\/p>\n<ul dir=\"ltr\">\n<li><strong>Seamless or welded tubes:<\/strong> seamless tubes have no weld seam along their length, which makes them suitable for high pressures and temperatures and for the most critical services. Welded tubes, manufactured and treated according to specific heat exchanger standards, offer uniform wall thickness and excellent dimensional accuracy at a lower cost. For this reason, they are widely used in many applications.<\/li>\n<li><strong>Dimensional tolerances:<\/strong> outside diameter and wall thickness must meet tight tolerances. The tubes are inserted into the holes of the tube sheets and secured by expansion or welding, and even minimal deviations can compromise the tightness of the joint.<\/li>\n<li><strong>Wall thickness:<\/strong> a thinner wall improves heat transfer. However, the tube must still withstand the operating pressure and provide an adequate margin against corrosion and erosion, so the choice is always a balance between efficiency and safety.<\/li>\n<li><strong>Surface finish:<\/strong> a smooth inner surface limits the build-up of deposits and fouling, which reduce the efficiency of the heat exchanger, and makes cleaning easier. In the food and pharmaceutical sectors, surface roughness is often a design requirement.<\/li>\n<li><strong>Heat treatment:<\/strong> in stainless steel tubes, solution annealing restores the material structure after processing and preserves its corrosion resistance.<\/li>\n<li><strong>Testing and certification:<\/strong> several checks ensure the traceability of each tube and its compliance with the required specifications. These include hydrostatic testing, non-destructive testing such as eddy current or ultrasonic inspection, and inspection certificates according to EN 10204 3.1.<\/li>\n<\/ul>\n<h2 dir=\"ltr\"><\/h2>\n<h2 dir=\"ltr\">Fields of application<\/h2>\n<p dir=\"ltr\">Heat exchangers are found in <a href=\"https:\/\/tecratubes.com\/en\/fields\/\" target=\"_blank\" rel=\"noopener\"><strong>many sectors<\/strong><\/a>, and each one places specific demands on the tube, depending on the fluid handled and the operating conditions.<br \/>\nThe main fields of application are:<\/p>\n<ul dir=\"ltr\">\n<li><strong>Chemical, petrochemical and oil plants:<\/strong> aggressive fluids, acids and high temperatures require materials with high corrosion resistance, such as AISI 316L, Duplex and nickel alloys.<\/li>\n<li><strong>Refineries:<\/strong> sulfur compounds, chlorides and severe temperature and pressure conditions steer the choice towards nickel alloys, Duplex and Superduplex. Carbon steel is also used for less aggressive services.<\/li>\n<li><strong>Marine applications:<\/strong> seawater is rich in chlorides and prone to biofouling. Seawater-cooled heat exchangers mainly use copper-nickel 90\/10 and 70\/30 and Superduplex.<\/li>\n<li><strong>Food industry:<\/strong> hygiene and ease of cleaning, including with CIP systems, make AISI 304L and 316L stainless steels the most common choice.<\/li>\n<li><strong>Pharmaceutical and biotechnology industries:<\/strong> fluid purity, sterilization cycles and controlled surface finishes steer the choice towards AISI 316L.<\/li>\n<li><strong>Water treatment:<\/strong> chloride content varies widely, up to brackish water and desalination plants, and calls for materials such as Duplex, Superduplex and copper-nickel.<\/li>\n<li><strong>HVAC systems:<\/strong> in refrigeration and air conditioning, copper is the preferred material thanks to its high thermal conductivity and ease of processing.<\/li>\n<\/ul>\n<h2 dir=\"ltr\"><\/h2>\n<h2 dir=\"ltr\">Materials<\/h2>\n<p dir=\"ltr\"><strong>Many different materials<\/strong> can be used to build heat exchangers, each with specific characteristics.<\/p>\n<h3 dir=\"ltr\">Austenitic stainless steels<\/h3>\n<p dir=\"ltr\">Among the most common materials are AISI 304L and 316L stainless steels, valued for their ease of cleaning and corrosion resistance. 304L is suitable for mildly aggressive fluids and for applications where hygiene is a priority. 316L contains molybdenum and therefore offers superior resistance in chloride-containing environments. The low carbon content of both ensures reliable welds without loss of corrosion resistance. For even more demanding conditions, AISI 317L can be used, as it has a higher molybdenum content.<\/p>\n<h3 dir=\"ltr\">Duplex and Superduplex<\/h3>\n<p dir=\"ltr\">Duplex and Superduplex steels have an austenitic-ferritic structure. They combine high mechanical strength with excellent resistance to stress corrosion cracking and to chloride-induced pitting corrosion. Their higher mechanical strength allows tubes to be designed with thinner walls, which benefits heat transfer. They are used in offshore applications, desalination plants and the petrochemical sector.<\/p>\n<h3 dir=\"ltr\">Nickel and nickel alloys<\/h3>\n<p dir=\"ltr\">Nickel and nickel alloys are suited to the most severe conditions: high pressures, high temperatures and highly corrosive environments.<\/p>\n<ul dir=\"ltr\">\n<li><strong>Inconel 625:<\/strong> resists seawater, chlorides and stress corrosion cracking, even at high temperatures.<\/li>\n<li><strong>Incoloy 825:<\/strong> is suitable in the presence of strong acids such as sulfuric and phosphoric acid.<\/li>\n<li><strong>Hastelloy:<\/strong> stands out in particularly aggressive chemical environments.<\/li>\n<li><strong>Monel:<\/strong> performs well in seawater and in the presence of hydrofluoric acid.<\/li>\n<\/ul>\n<h3 dir=\"ltr\">Copper and copper alloys<\/h3>\n<p dir=\"ltr\">Copper and copper alloys are used especially in refrigeration and air conditioning, as they are excellent thermal conductors.<\/p>\n<p dir=\"ltr\">Among copper alloys, copper-nickel 90\/10 and 70\/30 is a well-established solution for condensers and heat exchangers in contact with seawater, thanks to its resistance to marine corrosion and biofouling. 70\/30 is preferred where higher fluid velocities are expected.<\/p>\n<h3 dir=\"ltr\">Other materials<\/h3>\n<p dir=\"ltr\">In some cases, titanium is also used, as its extremely high corrosion resistance makes it suitable for highly corrosive environments. Carbon steel is a cost-effective solution for services with mildly aggressive fluids. Finally, aluminum is characterized by its light weight and good thermal conductivity.<\/p>\n<h2 dir=\"ltr\"><\/h2>\n<h2 dir=\"ltr\">Comparison of the main materials<\/h2>\n<div style=\"overflow-x: auto; margin: 20px 0; font-family: 'Montserrat',Arial,sans-serif;\">\n<table style=\"width: 100%; min-width: 640px; border-collapse: collapse; font-size: 14px; line-height: 1.4;\">\n<thead>\n<tr style=\"background: #0B2A4A; color: #fff; text-align: left;\">\n<th style=\"padding: 12px; border: 1px solid #d9e2ec;\">Material<\/th>\n<th style=\"padding: 12px; border: 1px solid #d9e2ec;\">Corrosion resistance<\/th>\n<th style=\"padding: 12px; border: 1px solid #d9e2ec;\">Thermal conductivity<\/th>\n<th style=\"padding: 12px; border: 1px solid #d9e2ec;\">High temperatures<\/th>\n<th style=\"padding: 12px; border: 1px solid #d9e2ec;\">Typical applications<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec; background: #3FA9D8; color: #fff; font-weight: bold;\">AISI 304L<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Good<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Low<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Good<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Food, pharmaceutical, mildly aggressive fluids<\/td>\n<\/tr>\n<tr style=\"background: #f3f7fa;\">\n<td style=\"padding: 10px; border: 1px solid #d9e2ec; background: #3FA9D8; color: #fff; font-weight: bold;\">AISI 316L<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">High, including with chlorides<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Low<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Good<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Chemical, food, pharmaceutical<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec; background: #3FA9D8; color: #fff; font-weight: bold;\">Duplex and Superduplex<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Very high, including with chlorides<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Low<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Limited<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Offshore, desalination, petrochemical<\/td>\n<\/tr>\n<tr style=\"background: #f3f7fa;\">\n<td style=\"padding: 10px; border: 1px solid #d9e2ec; background: #3FA9D8; color: #fff; font-weight: bold;\">Nickel alloys<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Excellent<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Low<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Excellent<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Chemical, refining, oil &amp; gas<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec; background: #3FA9D8; color: #fff; font-weight: bold;\">Copper<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Good in fresh water<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Very high<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Limited<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">HVAC, refrigeration<\/td>\n<\/tr>\n<tr style=\"background: #f3f7fa;\">\n<td style=\"padding: 10px; border: 1px solid #d9e2ec; background: #3FA9D8; color: #fff; font-weight: bold;\">Copper-nickel 90\/10 and 70\/30<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">High in seawater<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Medium<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Medium<\/td>\n<td style=\"padding: 10px; border: 1px solid #d9e2ec;\">Marine, offshore, condensers<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<h2 dir=\"ltr\"><\/h2>\n<h2 dir=\"ltr\">How to choose the right material<\/h2>\n<p dir=\"ltr\">Within this wide range, the choice of the most suitable material depends on <strong>several parameters<\/strong>, which must be considered to ensure the efficiency and long service life of the heat exchanger itself. The most important include:<\/p>\n<ul dir=\"ltr\">\n<li><strong>Operating temperature and pressure:<\/strong> they determine the mechanical strength and wall thickness of the tube. They can also rule out materials that lose performance at high temperatures.<\/li>\n<li><strong>Fluid type:<\/strong> chemical composition, suspended solids and flow velocity affect corrosion, erosion and the build-up of deposits.<\/li>\n<li><strong>Environmental corrosion level:<\/strong> chlorides, acids and marine environments require specific materials, from AISI 316L up to nickel alloys.<\/li>\n<li><strong>Required thermal conductivity:<\/strong> it affects heat transfer efficiency and the size of the heat exchanger.<\/li>\n<li><strong>Maintenance and cleaning:<\/strong> the frequency of maintenance and the cleaning methods planned point towards suitable materials and finishes.<\/li>\n<li><strong>Life cycle cost:<\/strong> a higher-performance material may require a greater initial investment, but it reduces replacements, plant shutdowns and maintenance costs over time.<\/li>\n<\/ul>\n<p dir=\"ltr\">Tecra supports you in choosing the most suitable solution for your needs.<br \/>\n<a href=\"https:\/\/tecratubes.com\/en\/contacts\/\" target=\"_blank\" rel=\"noopener\"><strong>For more information or to receive a dedicated quotation<\/strong><\/a>, our team is at your disposal.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Heat exchangers are essential components in many industrial sectors, such as oil &amp; gas, petrochemical and energy. They are part of a system in which thermal energy is exchanged between fluids at different temperatures. Selecting the most suitable tubes for building heat exchangers is essential, since they must comply with strict standards to ensure high [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":8396,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[48],"tags":[],"class_list":["post-8395","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"acf":[],"permalink_manager":null,"_links":{"self":[{"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/posts\/8395","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/comments?post=8395"}],"version-history":[{"count":2,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/posts\/8395\/revisions"}],"predecessor-version":[{"id":8399,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/posts\/8395\/revisions\/8399"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/media\/8396"}],"wp:attachment":[{"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/media?parent=8395"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/categories?post=8395"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tecratubes.com\/en\/wp-json\/wp\/v2\/tags?post=8395"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}