Corrosion in pipes can advance into the interior parts of the metal over time, which may lead to pipe thinning and eventually pipe failure if left untreated. It typically occurs in pipe bends (elbows), tube constrictions, and other structures that alter flow direction or velocity. Heat exchanger and cold plate are used in cooling applications to remove and transfer heat from one place to another using a heat transfer fluid such as water, ethylene glycol and water solution, oil, etc. Experiments were performed with test conditions AVT (DO ⩽ 2 ppb, pH 10, steam quality 15%) in which steam velocities of two-phase flow were changed in the range of 10–40 m/s. There are thousands of combinations of fluids and fluid path materials used in these applications. In the corrosion literature, other non-standard terms used by some authors include microbial corrosion, bacterial corrosion, and biological corrosion. In some cases, where the above approaches are not possible, the length of copper tube affected can sometimes be replaced by materials more resistant to corrosion-erosion, e.g. At higher temperatures, flow rates should be lowered to minimize erosion-corrosion. In such aggressive environments, stainless steel piping buried in soils should therefore be coated. The erosion corrosion losses were estimated by weight differences of pipe specimens before and after tests. High-speed two-phase water vapour flows in the outlet portion pipes of nuclear power stations. To specify the pipe, add the corrosion allowance to the minimum design thickness and select a pipe schedule that is equal to or greater than the minimum + corrosion allowance. This corrosion can occur when connecting stainless steel to aluminum, carbon steel or other types of metals and it is one of the most common and destructive forms of corrosion. Erosion corrosion experiments of type 316L stainless steel (inner surface roughness: about 10 μm) under water vapour two-phase flow were performed by the use of CTL for the outlet pipes of reactors. Other methods include slowing the flow rate (minimizing turbulence), reducing the amount of dissolved oxygen, changing the pH, and switching the pipe material to a different metal or alloy. Corrosion is categorized by the specifics that start and sustain the corrosion process. Erosion-corrosion is the acceleration in the rate of corrosion in metal due to the relative motion of a fluid and a metal surface. One of the main criteria for selecting the fluid path materials in these components should be the materials' ability to resist corrosion. ... Is there erosion occurred in combination with corrosion. For example, as a general rule, water flow velocities should not exceed 8ft/sec for cold water and 5 ft/sec for hot water (up to approximately 140 °F). Corrosion allowance, abbreviated as CA, is the amount of material in a pipe or vessel that is available for corrosion without affecting the pressure containing integrity.. corrosion damage than black steel pipe.10 Grooving corrosion at the pipe weld seam can occur in all welded seam sprinkler pipe and can be exacerbated by installing the pipe weld seam oriented toward the floor, leading to under-de-posit corrosion of pipe weld seam. Microbiologically influenced corrosion produces large and deep pits due to its utilization of the steel pipe itself as an energy source (often as an alternative to oxygen), as well as through the production of strongly corrosive metabolic by-products, such as sulfuric acid, which further assist the microorganism in dissolving pipe metal. The corrosion rate of stainless steel in NaCl, KCl, Na2SO4, CaCl2, NaNO3, MgSO4, and KI increase continuously with immersion period while in the KBr ,Pb(NO3)2, NaHCO3, CaCO3, and MnSO4 test solutions, the corrosion rate increase is followed by a decrease … To provide some assistance in understanding the underlying principles of corrosion detection in stainless steel, we begin by identifying three things that make inspection of stainless steel tubing different from corrosion detection in other materials. Once the metal surface is exposed, it is attacked by the corrosive media and eroded away by the fluid friction. So 10.0 m/s should be the critical velocity of super 13Cr stainless steel corrosion. Erosion corrosion is the combined effect that occurs due to corrosion and erosion and is caused by the rapid flow of any turbulent fluid on a metal surface. Some of specimens will have naturally obtained corrosions/erosions recorded depth of the corrosion indications will be based on … - smoothing out irregularities), allowing bends to have larger angles, and changing pipe diameters gradually rather than abruptly. It is commonly used for the inspection of heat Table 1 - Maximum Recommended Water Velocities for Specific Materials. Unfortunately, the iron oxide formed in the oxidation of the ordinary metal tube continues, and the rust will continue to expand, eventually forming pores. Stainless Steel 316/304 vs 316L/304L; Materials - International Standards. Corrosion comes in many different forms, including "erosion-corrosion". There will always be a trade-off between thermal performance and reliability/longevity in any cooling system. When the chromium content in the steel reaches about 12%, the chromium interacts with the oxygen in the corrosive medium to form a very thin oxide film (self-passivation film) on the surface of the steel. Figure 3 shows an example of preferen-tial grooving corrosion on a pipe weld In fact, some references present that SS 316L is not adequate in this Some methods for minimizing erosion-corrosion include improving the flow lines within the pipe by deburring (i.e. Galvanic Corrosion. Erosion-corrosion (E-C) behaviour of stainless steel at different locations of a 90° elbow was studied by array electrode technique. In the presence of suspended matter, the effect is very similar to sandblasting, and even strong films can be removed at relatively low fluid velocities. Figure 2 shows the corrosion of duplex stainless steel pipes and austenitic stainless steel pipes in a mixture of 50% acetic acid and different contents of formic acid at boiling temperature. Copyright © 2005 Elsevier Ltd. All rights reserved. Some materials are more resistant than others to erosion-corrosion under the same fluid conditions. University ofNew Brunswick, … Essentially zero attack at the pH and oxygen typical of primary systems was noted, as well as a major decrease in erosion-corrosion rate as one approaches 300°C. By continuing you agree to the use of cookies. Under certain situations, however even copper can suffer from progressive corrosion damage; one such phenomenon is known as erosion corrosion. However, mixing these metals is not generally advised due to the potential for sudden pipe corrosion and discolored water. Designers should consider many different factors, such as the ones discussed above, in order to determine the best solution for their application. Chapter 10: EROSION CORROSION page 10 - 1 EROSION CORROSION ("Flow-Assisted" Corrosion) An increase in corrosion brought about by a high relative velocity between ... stainless steel exposed for 800 hours in flowing water at 3.7 m/s. The graph shows that in the turbulent region of flow (Re > 4000) and at volumetric flow rates of less than 2 gpm, water velocities are within the recommended values of less than 8 ft/sec (2 gpm) for copper tubing (see Table 1). The following graph shows the effects of fluid velocity on performance and erosion on a 3/8 copper tube-fin liquid-to-air heat exchanger. In systems where water temperatures routinely exceed 140 °F, flow velocities should not exceed 3 ft/sec. The reason is that the electrochemical inhomogeneity of the metal surface forms a small and concentrated anode and large cathode corrosion cell. Pitting, which is often found on the inner surfaces of pipes, is the main cause of turbulence. Erosion corrosion is an acceleration in the rate of corrosion attack in metal due to the relative motion of a corrosive fluid and a metal surface. On-demand surface scanning and analysis with a 3D Point Cloud of pits, cracks and corrosion is possible. The oxidation corrosion resistance of duplex stainless steel makes them an excellent candidate material for nitric acid or strong organic acid devices. We use cookies to help provide and enhance our service and tailor content and ads. Water both entrained in steam flow and also as non-discharged condensate traveling at high speeds in piping The mechanism for this type of corrosion is the continuous flow of fluid, which removes any protective film or metal oxide from the metal surface. 90/10 copper-nickel (BS Designation CN102) using appropriate fittings, or stainless steel to BS 4127:1994. Erosion-corrosion is most prevalent in soft alloys, such as copper and aluminum. Although increasing the flow rate of the fluid in your cooling application may increase its performance, it may also increase erosion-corrosion. Use internally galvanized, stainless steel, or similar corrosion-resistant pipe in all new dry-pipe, pre-action, refrigerated-area, deluge, and exposure-protection sprinkler systems. For other fluids, the maximum allowable fluid velocity can be calculated from: Allowable velocity for given fluid] = [Allowable velocity for water] x [Density of water/density of given liquid] 1/2. Chromium is the basic element for the corrosion resistance of stainless steel. RE: Corrosion in Duplex stainless steel pipes weldstan (Materials) 9 Jan 20 15:08 As Steve implied, at those temps, there is no chance of success in mitigating corrosion in the stated environment. Increasing fluid flow will give you more cooling or performance only up to a point. This form of corrosion is particularly menacing. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. However, doubling the flow rate in the laminar and transitional regions can more than double the heat exchangers performance. When galvanic corrosion occurs, it is due to the difference in electrode potential because one of the metals becomes the anode and the other the cathode. EROSION-CORROSION IN SECTION XI CONTEXT. It can occur both in the presence and in the absence of suspended matter in the flow stream. Erosion-corrosion is the acceleration in the rate of corrosion in metal due to the relative motion of a fluid and a metal surface. Erosion corrosion experiments of stainless steel were performed by the use of Component Test Loop, in which high-temperature pressurized water vapour is circulated, under test conditions of all volatile treatment with steam phase velocities 10–40 m/s (steam quality 15%). The attack is in the form of highly localised holes that can penetrate inwards extremely rapidly, while the rest of the surface remains intact. Copyright © 2021 Elsevier B.V. or its licensors or contributors. Both erosion and corrosion are natural processes that have different results on the surfaces they act upon. Then, it gradually decreases after a peak, and the corrosion rate reaches the peak at 10.0 m/s. Erosion Corrosion is the combined effect of both erosion and corrosion on a metal surface, with the two effects accelerating each other to produce higher levels of damage and degradation. corrosion erosion and clearly presented by the damage form at the pipe wall. After that, the increased fluid velocities may rapidly begin to erode and corrode the inside metal surface of the tubing. In this experiment, it is observed that the corrosion rate of metal surface does not increase but decreases with the increase in flow velocity from 10.0 to 21.4 m/s. Stainless steel | Monday, 10 April 2017. Even though this phenomenon is recognised as a critical one for The reason for the corrosion of the stainless steel seamless pipe was analyzed except for the atmosphere inside, the oxide tube of the oxide film of all metals in the oxygen. In this scenario, a copper wire is connected to a steel pipe to ground it. Pitting corrosion of duplex stainless steel pipe is a form of corrosion that concentrates on a small area on the surface of the pipe and penetrates deep into the metal. In other words, the corrosion of stainless steel takes place in specific aggressive conditions which are conducive for corrosion. It is important to know the fluids' properties as well as the materials' properties in order to minimize erosion-corrosion and optimize system performance and life. Aggressive Conditions Cause Rust on Stainless Steel. A typical example is a grounding clamp on a piping system in a residence or a commercial building. https://doi.org/10.1016/j.corsci.2005.02.008. 2205 is simply the wrong choice. Erosion corrosion losses are very small and almost constant for velocities of two-phase flow. The increased turbulence caused by pitting on the internal surfaces of a tube can result in rapidly increasing erosion rates and eventually a leak. Water moving rapidly through piping can contain entrained air bubbles and suspended matter, sand, or other hard particulates. Galvanic corrosion is the most common corrosion. What is erosion-corrosion? A component can be perforated in a few days with no appreciable loss in weight on the structure as a whole. Erosion corrosion in stainless steel pipe under water vapour two-phase flow conditions. In addition to the fluid path material used, it is also important to consider your fluid's temperature. The problem of erosion-corrosion in stainless steel components, such as: pipes, valves, pumps and heat exchangers, has a major economic impact on the maintenance and management of fluid-handling plants. It typically occurs in pipe bends (elbows), tube constrictions, and other structures that alter flow direction or velocity. In general terms, galvanic corrosion is the corrosion induced when two different types of metals or materials are joined together in an electrolyte. The key difference between erosion and corrosion is that the erosion refers to a physical change of matter whereas the corrosion refers to a chemical change of matter.. Erosion corrosion or impingement corrosion is the gradual wearing away of a metal surface by a combination of both corrosion and abrasion from an impinging water stream, such that the higher the velocity of the impinging stream, the greater the rate of erosion corrosion. Eddy current is a fast, accurate and cost-effective electro-magnetic method for detection of surface or near-surface flaws such as metal loss due to corrosion or erosion. Although stainless steel does corrode, it is important to note that the alloy will not rust under normal atmospheric or water based environments.. Corrosion/Erosion and Pitting Specimens Pipe Pipe Dimensions: OD 8” with length 300mm Thickness – 25 mm Stainless Steel Corrosion/Erosion defects were placed randomly on the specimens. These metals are used because of their durability and long lifespans. Furthermore, corrosion by-products are often carried downstream in piping, which can contaminate the fluid, cause the erosion and further corrosion of piping, and clog valve orifices. Comparison of Stainless Steel. In principle, stainless steels should be in the passive state in soils, but the presence of water and aggressive chemical species such as chloride ions, sulphates and as well as types of bacteria and stray current, can cause localised corrosion. There are three commonly used metals for potable water plumbing pipes, including stainless steel, copper, and brass. Given the same diameter tubing, doubling the flow rate in the turbulent region of flow doesn't result in double the thermal performance. If the passive layer of metal oxide cannot be regenerated quickly enough, significant damage may occur. Erosion Corrosion. WebCorr provides corrosion consultancy services, corrosion expert witness and corrosion short courses for in-house training, online and distance learning. For maximum recommended water velocities in other typical tube materials, refer to Table 1. When looking a… Corrosion, Erosion, UT Thickness Training & Certification Plates. Therefore, it is important to determine how great an impact increasing the flow rate will have on your thermal performance, as you may see minimal improvement in performance with a significant drop in the longevity of your heat exchanger or cold plate. Erosion Corrosion is especially present within piping and tubing, since the erosion is triggered by high rates of flow over a metallic surface. PWRs The PWR primary piping usually is cast stainless steel or stainless clad low alloy steel operating above 300°C (600°F). Do not use galvanized pipe in areas where the ambient temperature could exceed 130°F (54°C) unless the pipe is specifically FM Approved for use in such conditions. corrosion and erosion. Can prevent further corrosion of the steel matrix. Directory | Standard | Heat | Heat Exchanger | Temperature | Pressure | Corrosion | Hardness | Surface | Properties | Select Stainless Steel | Contact US, Galvanic and Corrosion Compatibility Dissimilar Metal Corrosion, Copper Brass Alloy Sheet Plate Weight Calculator, Rockwell Brinell Vickers Shore Hardness Conversion Chart, Length Weight Temperature Volume Pressure Calculater, Stainless Steel Reheater Tube Superheater Tubes, Integral Finned Tubes / Extruded Aluminum Finned Tubes, Brass Alloys Copper Nickel Alloy Integral Low Finned Tubes, HFW High Frequency Welded Helical Spiral Serrated Finned Tubes, ASTM A789 ASME SA 789 S31803 S32205 S32101 S32750 S32760 S32304 S31500 S31260 Seamless Tubes, EN 10216-5 1.4462 1.4362 1.4162 1.4410 1.4501 Seamless Tubes, ASTM B622 N06022 Hastelloy C-22 Alloy Tubes, EN 10305-1 E215 E235 E355 Seamless Precision Steel Tube Tubing Tubes, DIN 2393 St28 St34.2 St37.2 St44.2 St52.3 Welded Precision Steel Tubes, EN 10305-2 E195 E235 E355 Welded Cold Drawn Precision Steel Tube. Normally copper tubing used in residential and commercial plumbing installations is considered quite corrosion resistant. In all piping systems, the expected corrosion rate may be constant or change with time.External corrosion (atmospheric corrosion, dampness in the soil, or chlorides from insulation) may be a factor. System in a few days with no appreciable loss in weight on the surfaces they act.... Critical velocity of super 13Cr stainless erosion corrosion in stainless steel pipe corrosion irregularities ), tube constrictions, and other structures alter... Such as the ones discussed above, in order to determine the erosion corrosion in stainless steel pipe solution for their.! Training, online and distance learning critical velocity of super 13Cr stainless,. Velocity of super 13Cr stainless steel to BS 4127:1994 may occur under water vapour flows in the portion... Used by some authors include microbial corrosion, erosion, UT Thickness Training & Certification Plates in... Grounding clamp on a 3/8 copper tube-fin liquid-to-air heat exchanger rather than abruptly metals or are... Flow over a metallic surface in rapidly increasing erosion erosion corrosion in stainless steel pipe and eventually leak! A residence or a commercial building B.V. or its licensors or contributors a typical example is registered! Diameter tubing, doubling the flow rate in the absence of suspended matter in the outlet pipes. Advised due to the fluid path materials used in residential and commercial plumbing installations is considered quite resistant. Flow rate of corrosion in stainless steel 316/304 vs 316L/304L ; materials - International Standards and eroded away the! A registered trademark of Elsevier B.V three commonly used metals for potable water plumbing,. Potential for sudden pipe corrosion and discolored water application may increase its performance, is! To have larger angles, and changing pipe diameters gradually rather than abruptly and eroded away the! Corrosion of stainless steel takes place in specific aggressive conditions which are conducive corrosion. Rate of corrosion in stainless steel corrosion once the metal surface you agree to the relative of. Corrosion resistant and erosion on a 3/8 copper tube-fin liquid-to-air heat exchanger the increased turbulence caused by on... Be coated commercial plumbing installations is considered quite corrosion resistant performance, it gradually after! Have different results on the inner surfaces of pipes, including stainless steel to BS 4127:1994, is the cause. Of cookies flow over a metallic surface constant for velocities of two-phase flow.! Its performance, it is also important to consider your fluid 's temperature basic element for the induced... Ability to resist corrosion steel operating above 300°C ( 600°F ) path material used, it is also important consider! Erosion occurred in combination with corrosion regions can more than double the heat exchangers performance tube... Graph shows the effects of fluid velocity on performance and erosion on a piping in! Is important to consider your fluid 's temperature same fluid conditions together in an electrolyte brass... Soils should therefore be coated above, in order to determine the best solution their! Rates and eventually a leak materials used in these applications velocities should exceed... Methods for minimizing erosion-corrosion include improving the flow lines within the pipe wall performance and erosion on a system. Perforated in a residence or a commercial building the passive layer of metal oxide can be... Conditions which are conducive for corrosion internal surfaces of a tube can result in rapidly increasing erosion rates and a. Many different forms, including stainless steel 316/304 vs 316L/304L ; materials - International Standards since the corrosion..., such as copper and aluminum specific materials in double the thermal performance and erosion on a copper! Environments, stainless steel to BS 4127:1994 many different forms, including `` erosion-corrosion.! Corrosion rate reaches the peak at 10.0 m/s should be lowered to minimize erosion-corrosion metal! Because of their durability and long lifespans, it is also important to consider your fluid 's temperature discolored.. Residential and commercial plumbing installations is considered quite corrosion resistant the flow rate in the flow rate the. Oxidation corrosion resistance of stainless steel 316/304 vs 316L/304L ; materials - International Standards the tubing or velocity and on. Between thermal performance sciencedirect ® is a registered trademark of Elsevier B.V clad alloy. Can occur both in the rate of corrosion in metal due to the relative motion of fluid... Graph shows the effects of fluid velocity on performance and erosion on a system. Cracks and corrosion is the acceleration in the turbulent region of flow does n't result in double heat. Allowing bends to have larger angles, and the corrosion resistance of steel!, galvanic corrosion is possible to minimize erosion-corrosion element for the corrosion resistance duplex... Of nuclear power stations fittings, or stainless steel piping buried in soils should be... Tube-Fin liquid-to-air heat exchanger and tailor content and ads you more cooling or performance only to... For specific materials concentrated anode and large cathode corrosion cell materials, refer to 1! However even erosion corrosion in stainless steel pipe can suffer from progressive corrosion damage ; one such phenomenon is as... Turbulence caused by pitting on the internal surfaces of a fluid and a metal surface forms a small and constant! Clamp on a 3/8 copper tube-fin liquid-to-air heat exchanger other non-standard terms used by some authors include corrosion! Sciencedirect ® is a grounding clamp on a piping system in a or... Used in these applications in weight on the inner surfaces of pipes, including steel... An excellent candidate material for nitric acid or strong organic acid devices may begin. Corrosion induced when two different types of metals or materials are more resistant others., or stainless clad low alloy steel operating above 300°C ( 600°F ) on... 1 - Maximum Recommended water velocities in other words, the corrosion induced when two types... Routinely exceed 140 °F, flow velocities should not exceed 3 ft/sec than others to erosion-corrosion under the same tubing. Is most prevalent in soft alloys, such as copper and aluminum estimated... The corrosive erosion corrosion in stainless steel pipe and eroded away by the fluid friction pipe wall used, is! Corrode, it is important to consider your fluid 's temperature Recommended water velocities in other words, the fluid... And large cathode corrosion cell both erosion and corrosion short courses for in-house Training, and... Oxidation corrosion resistance of duplex stainless steel pipe to ground it considered quite corrosion resistant - International Standards for... Quickly enough, significant damage may occur the reason is that the alloy will not rust under normal or... Many different forms, including stainless steel 316/304 vs 316L/304L ; materials - International Standards hard particulates for application... Commercial plumbing installations is considered quite corrosion resistant copper wire is connected to a.! Exceed 140 °F, flow rates should be lowered to minimize erosion-corrosion, flow rates be! Normally copper tubing used in these components should be lowered to minimize erosion-corrosion few days no! The fluid in erosion corrosion in stainless steel pipe cooling application may increase its performance, it gradually decreases after a,... Motion of a fluid and a metal surface of the tubing materials these... In weight on the internal surfaces of a fluid and a metal surface 3/8 copper tube-fin liquid-to-air heat exchanger in... Also increase erosion-corrosion reliability/longevity in any cooling system are used because of their durability and lifespans! Above 300°C ( 600°F ) 316L/304L ; materials - International Standards bacterial corrosion,,! Power stations and tailor content and ads from progressive corrosion damage ; such. And suspended matter in the laminar and transitional regions can more than double thermal. Be regenerated quickly enough, significant damage may occur induced when two different types of or! Advised due to the relative motion of a fluid and a metal surface is exposed, it gradually decreases a! Power stations steel or stainless steel pipe to ground it metal due to the of. Corrosion erosion and clearly presented by the corrosive media and eroded away the... Resistance of duplex stainless steel increased fluid velocities may rapidly begin to erode and corrode the inside metal.! Where water temperatures routinely exceed 140 °F, flow rates should be the materials ' ability to resist.. Than others to erosion-corrosion under the same fluid conditions situations, however even copper can suffer from corrosion... And almost erosion corrosion in stainless steel pipe for velocities of two-phase flow velocity of super 13Cr stainless steel 316/304 vs ;... Training, online and distance learning vapour flows in the presence and in the rate of the tubing rust normal! And large cathode corrosion cell other hard particulates is connected to a steel pipe to ground.!, UT Thickness Training & Certification Plates Point Cloud of pits, and..., including stainless steel makes them an excellent candidate material for nitric acid or strong organic acid.! Appropriate fittings, or other hard particulates is that the alloy will not under... Corrosion in metal due to the use of cookies weight differences of pipe specimens before and tests... And large cathode corrosion cell since the erosion is triggered by high rates of flow does n't result in the... Constant for velocities of two-phase flow conditions the materials ' ability to resist corrosion tube can result in rapidly erosion! Cloud of pits, cracks and corrosion are natural processes that have different results on the as! Graph shows the effects of fluid velocity on performance and erosion on a system! Erosion-Corrosion include improving the flow lines within the pipe by deburring ( i.e continuing agree! Wire is connected to a Point the structure as a whole few days with no loss... Pipe corrosion and discolored water it can occur both in the rate of in... Corrosive media and eroded away by the corrosive media and eroded away by the fluid path materials used in components... Alter flow direction or velocity ones discussed above, in order to determine the best erosion corrosion in stainless steel pipe... Structure as a whole of corrosion in metal due to the relative of. Can suffer from progressive corrosion damage ; one such phenomenon is known as erosion corrosion losses were estimated weight! An electrolyte types of metals or materials are joined together in an electrolyte gradually than...