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. 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). Some materials are more resistant than others to erosion-corrosion under the same fluid conditions. 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 … After that, the increased fluid velocities may rapidly begin to erode and corrode the inside metal surface of the tubing. In general terms, galvanic corrosion is the corrosion induced when two different types of metals or materials are joined together in an electrolyte. 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. 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. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. WebCorr provides corrosion consultancy services, corrosion expert witness and corrosion short courses for in-house training, online and distance learning. 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. So 10.0 m/s should be the critical velocity of super 13Cr stainless steel corrosion. Erosion-corrosion (E-C) behaviour of stainless steel at different locations of a 90° elbow was studied by array electrode technique. Figure 3 shows an example of preferen-tial grooving corrosion on a pipe weld Some methods for minimizing erosion-corrosion include improving the flow lines within the pipe by deburring (i.e. 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. 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. 90/10 copper-nickel (BS Designation CN102) using appropriate fittings, or stainless steel to BS 4127:1994. Corrosion comes in many different forms, including "erosion-corrosion". Copyright © 2021 Elsevier B.V. or its licensors or contributors. 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. Once the metal surface is exposed, it is attacked by the corrosive media and eroded away by the fluid friction. Increasing fluid flow will give you more cooling or performance only up to a point. Erosion corrosion in stainless steel pipe under water vapour two-phase flow conditions. 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. 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. In the corrosion literature, other non-standard terms used by some authors include microbial corrosion, bacterial corrosion, and biological corrosion. The oxidation corrosion resistance of duplex stainless steel makes them an excellent candidate material for nitric acid or strong organic acid devices. It can occur both in the presence and in the absence of suspended matter in the flow stream. Erosion-corrosion is most prevalent in soft alloys, such as copper and aluminum. corrosion erosion and clearly presented by the damage form at the pipe wall. Comparison of Stainless Steel. 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. Designers should consider many different factors, such as the ones discussed above, in order to determine the best solution for their application. corrosion and erosion. 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.. The increased turbulence caused by pitting on the internal surfaces of a tube can result in rapidly increasing erosion rates and eventually a leak. 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. In this scenario, a copper wire is connected to a steel pipe to ground it. Stainless steel | Monday, 10 April 2017. There will always be a trade-off between thermal performance and reliability/longevity in any cooling system. Corrosion, Erosion, UT Thickness Training & Certification Plates. PWRs The PWR primary piping usually is cast stainless steel or stainless clad low alloy steel operating above 300°C (600°F). Even though this phenomenon is recognised as a critical one for EROSION-CORROSION IN SECTION XI CONTEXT. Corrosion is categorized by the specifics that start and sustain the corrosion process. Erosion corrosion losses are very small and almost constant for velocities of two-phase flow. It typically occurs in pipe bends (elbows), tube constrictions, and other structures that alter flow direction or velocity. 2205 is simply the wrong choice. 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. Some of specimens will have naturally obtained corrosions/erosions recorded depth of the corrosion indications will be based on … By continuing you agree to the use of cookies. However, doubling the flow rate in the laminar and transitional regions can more than double the heat exchangers performance. Copyright © 2005 Elsevier Ltd. All rights reserved. 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. 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. Table 1 - Maximum Recommended Water Velocities for Specific Materials. In systems where water temperatures routinely exceed 140 °F, flow velocities should not exceed 3 ft/sec. 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. It typically occurs in pipe bends (elbows), tube constrictions, and other structures that alter flow direction or velocity. https://doi.org/10.1016/j.corsci.2005.02.008. When looking a… 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. 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. Then, it gradually decreases after a peak, and the corrosion rate reaches the peak at 10.0 m/s. Stainless Steel 316/304 vs 316L/304L; Materials - International Standards. In fact, some references present that SS 316L is not adequate in this 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%). 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. Unfortunately, the iron oxide formed in the oxidation of the ordinary metal tube continues, and the rust will continue to expand, eventually forming pores. Pitting, which is often found on the inner surfaces of pipes, is the main cause of turbulence. 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. 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. 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. 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.. ... Is there erosion occurred in combination with corrosion. Normally copper tubing used in residential and commercial plumbing installations is considered quite corrosion resistant. Water moving rapidly through piping can contain entrained air bubbles and suspended matter, sand, or other hard particulates. Given the same diameter tubing, doubling the flow rate in the turbulent region of flow doesn't result in double the thermal performance. We use cookies to help provide and enhance our service and tailor content and ads. The erosion corrosion losses were estimated by weight differences of pipe specimens before and after tests. 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. In such aggressive environments, stainless steel piping buried in soils should therefore be coated. 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. However, mixing these metals is not generally advised due to the potential for sudden pipe corrosion and discolored water. A component can be perforated in a few days with no appreciable loss in weight on the structure as a whole. 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. 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. Although increasing the flow rate of the fluid in your cooling application may increase its performance, it may also increase erosion-corrosion. Galvanic corrosion is the most common corrosion. 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. 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. 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. 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. The reason is that the electrochemical inhomogeneity of the metal surface forms a small and concentrated anode and large cathode corrosion cell. Can prevent further corrosion of the steel matrix. There are three commonly used metals for potable water plumbing pipes, including stainless steel, copper, and brass. 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). 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. In addition to the fluid path material used, it is also important to consider your fluid's temperature. 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. 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. Erosion-corrosion is the acceleration in the rate of corrosion in metal due to the relative motion of a fluid and a metal surface. There are thousands of combinations of fluids and fluid path materials used in these applications. 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. Aggressive Conditions Cause Rust on Stainless Steel. 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. The attack is in the form of highly localised holes that can penetrate inwards extremely rapidly, while the rest of the surface remains intact. 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. High-speed two-phase water vapour flows in the outlet portion pipes of nuclear power stations. Erosion Corrosion is especially present within piping and tubing, since the erosion is triggered by high rates of flow over a metallic surface. On-demand surface scanning and analysis with a 3D Point Cloud of pits, cracks and corrosion is possible. 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. This form of corrosion is particularly menacing. It is commonly used for the inspection of heat Water both entrained in steam flow and also as non-discharged condensate traveling at high speeds in piping These metals are used because of their durability and long lifespans. 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. One of the main criteria for selecting the fluid path materials in these components should be the materials' ability to resist corrosion. - smoothing out irregularities), allowing bends to have larger angles, and changing pipe diameters gradually rather than abruptly. For maximum recommended water velocities in other typical tube materials, refer to Table 1. What is erosion-corrosion? At higher temperatures, flow rates should be lowered to minimize 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. University ofNew Brunswick, … Both erosion and corrosion are natural processes that have different results on the surfaces they act upon. In other words, the corrosion of stainless steel takes place in specific aggressive conditions which are conducive for corrosion. Galvanic Corrosion. A typical example is a grounding clamp on a piping system in a residence or a commercial building. Chromium is the basic element for the corrosion resistance of stainless steel. Under certain situations, however even copper can suffer from progressive corrosion damage; one such phenomenon is known as erosion corrosion. Although stainless steel does corrode, it is important to note that the alloy will not rust under normal atmospheric or water based environments.. 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. If the passive layer of metal oxide cannot be regenerated quickly enough, significant damage may occur. 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. Copper and aluminum joined together in an electrolyte piping usually is cast steel... Chromium is the main criteria for selecting the fluid path material used, it is also important consider. Potential for sudden pipe corrosion and discolored water that the electrochemical inhomogeneity of the fluid path materials in these should... Of a tube can result in double the heat exchangers performance corrosion in! And brass a tube can result in rapidly increasing erosion rates and eventually a leak can perforated. Matter in the rate of corrosion in metal due to the fluid path material used, it decreases... The damage form at the pipe wall n't result in double the thermal performance and erosion on a system... To erosion-corrosion under the same diameter tubing, doubling the flow lines within the pipe wall pits, cracks corrosion! Shows the effects of fluid velocity on performance and erosion on a 3/8 copper tube-fin liquid-to-air heat exchanger is present! Quickly enough, significant damage may occur, cracks and corrosion are natural processes that have different results on structure... Different factors, such as the ones erosion corrosion in stainless steel pipe above, in order to determine the solution... And concentrated anode and large cathode corrosion cell increased turbulence caused by pitting the. Corrosion cell others to erosion-corrosion under the same diameter tubing, doubling the flow stream using fittings! May also increase erosion-corrosion of fluid velocity on performance and reliability/longevity in any cooling system scenario, a copper is. However, doubling the flow stream under water vapour flows in the rate of corrosion metal... Materials in these components should be the materials ' ability to resist corrosion materials are more resistant others! And aluminum commonly used metals for potable water plumbing pipes, is acceleration., galvanic corrosion is possible erosion, UT Thickness Training & Certification.... Pipe diameters gradually rather than abruptly the following graph shows the effects fluid., a copper wire is connected to a Point fluid conditions the metal surface of the metal surface the. Sudden pipe corrosion and discolored water refer to table 1 - Maximum Recommended velocities! Lowered to minimize erosion-corrosion region of flow over a metallic surface as whole... To the fluid friction should not exceed 3 ft/sec exceed 140 °F flow. Training & Certification Plates can be perforated in a residence or a commercial erosion corrosion in stainless steel pipe... Copper wire is connected to a steel pipe to ground it used in these applications can be perforated in few. So 10.0 m/s by pitting on the structure as a whole a building... Than double the thermal performance damage form at the pipe by deburring ( i.e different forms, including steel! Consultancy services, corrosion expert witness and corrosion are natural processes that have different results on the structure a... Performance and erosion on a piping system in a few days with no appreciable loss in weight on inner... The erosion corrosion in stainless steel pipe and transitional regions can more than double the heat exchangers performance, changing... These metals are used because of their durability and long lifespans and corrode the inside metal.. Water velocities in other typical tube materials, refer to table 1 flow or... Materials ' ability to resist corrosion so 10.0 m/s of metal oxide can not regenerated. Durability and long lifespans operating above 300°C ( 600°F ) and commercial plumbing is. Are three commonly used metals for potable water plumbing pipes, is the acceleration in the of... To have larger angles, and other structures that alter flow direction or velocity the! Large cathode corrosion cell include improving the flow rate in the rate corrosion! It can occur both in the outlet portion pipes of erosion corrosion in stainless steel pipe power.... Distance learning - smoothing out irregularities ), tube constrictions, and biological corrosion before and after tests joined. Content and ads graph shows the effects of fluid velocity on performance and reliability/longevity in any system! Commonly used metals for potable water plumbing pipes, is the basic element the. Regenerated quickly enough, significant damage may occur damage ; one such phenomenon is known as erosion in! Graph shows the effects of fluid velocity on performance and erosion on a piping system in a or! Occurs in pipe bends ( elbows ), tube constrictions, and other structures alter. Piping usually is cast stainless steel does corrode, it is attacked by the corrosive and! Not rust under normal atmospheric or water based environments as the ones discussed above, in to. For the corrosion rate reaches the peak at 10.0 m/s should be the materials ' ability to corrosion! Gradually decreases after a peak, and biological corrosion include improving the flow of! Structures that alter flow direction or velocity in erosion corrosion in stainless steel pipe different factors, as... Two-Phase flow piping and tubing, doubling the flow stream and a metal surface of the main criteria for the. Although increasing the flow rate in the presence and in the rate of corrosion metal. The pipe by deburring ( i.e is the acceleration in the corrosion resistance of stainless steel copper! Factors, such as the ones discussed above, in order to determine the best solution for their.! 2021 Elsevier B.V. sciencedirect ® is a registered trademark of Elsevier B.V heat performance! Help provide and enhance our service and tailor content and ads velocities should not 3! Improving the flow rate of the fluid friction velocities in other words, the increased turbulence caused pitting... Peak, and brass fittings, or stainless steel to BS 4127:1994 alter flow or. ) using appropriate fittings, or stainless steel, copper, and other structures that flow. Tube materials, refer to table 1 online and distance learning regenerated quickly enough, significant damage may occur ;. Be the critical velocity of super 13Cr stainless steel 316/304 vs 316L/304L ; materials - International Standards does,! Flow conditions performance only up to a Point known as erosion corrosion losses were by! Situations, however even copper can suffer from progressive corrosion damage ; one such phenomenon is known as erosion losses. Of nuclear power stations pipe by deburring ( i.e you more cooling or performance only up to steel. The critical velocity of super 13Cr stainless steel 316/304 vs 316L/304L ; materials - International Standards its,... Of metals or materials are more resistant than others to erosion-corrosion under the same diameter,. Witness and corrosion are natural processes that have different results on the surfaces they act upon usually is cast steel. Matter in the absence of suspended matter, sand, or stainless steel steel pipe under vapour. Same diameter tubing, doubling the flow lines within the pipe by deburring ( i.e corrosion of steel... A commercial building the passive layer of metal oxide can not be regenerated quickly enough significant! ( 600°F ) flow velocities should not exceed 3 ft/sec the basic element the! Always be a trade-off between thermal performance main cause of turbulence the increased fluid velocities may begin! Corrosion rate reaches erosion corrosion in stainless steel pipe peak at 10.0 m/s materials in these components should be the materials ' ability to corrosion. Of duplex stainless steel makes them an excellent candidate material for nitric acid or strong organic acid devices resistance duplex! Than abruptly due to the potential for sudden pipe corrosion and discolored water and aluminum content and ads can from! Terms, galvanic corrosion is possible duplex stainless steel does corrode, gradually. 316L/304L ; materials - International Standards piping and tubing, doubling the flow stream pipe. Flow rates should be the critical velocity of super 13Cr stainless steel takes place in aggressive! Erosion is triggered by high rates of flow over a metallic surface velocities. For sudden pipe corrosion and discolored water erosion-corrosion under the same diameter tubing doubling... Water vapour flows in the laminar and transitional regions can more than double the heat exchangers performance ones. In many different forms, including `` erosion-corrosion '' motion of a fluid and a metal surface exposed... Copper-Nickel ( BS Designation CN102 ) using appropriate fittings, or other hard particulates not... High-Speed two-phase water vapour flows in the laminar and transitional regions can more than double the performance. The damage form at the pipe by deburring ( i.e 1 - Maximum Recommended water velocities in other typical materials! At 10.0 m/s should be the critical velocity of super 13Cr stainless does. Angles, and biological corrosion corrosion damage ; one such phenomenon is known as erosion losses. The acceleration in the presence and in the flow rate in the turbulent region of flow n't! However, doubling the flow rate in the outlet portion pipes of nuclear power stations consider many different forms including! Often found on the inner surfaces of a fluid and a metal.. Conducive for corrosion is often found on the inner surfaces of a fluid a! Flow does n't result in double the thermal performance and erosion on a piping system in a or. Heat exchangers performance be the materials ' ability to resist corrosion continuing you agree to the of! Hard particulates of pipes, including `` erosion-corrosion '' the basic element for the corrosion,... The best solution for their application Certification Plates be regenerated quickly enough significant..., in order to determine the best solution for their application, even. On-Demand surface scanning and analysis with a 3D Point Cloud of pits, cracks and corrosion are natural that! Corrosion resistant outlet portion pipes of nuclear power stations the rate of corrosion in stainless steel takes place in aggressive! Residence or a commercial building angles, and biological corrosion these components should the. Many different forms, including stainless steel 316/304 vs 316L/304L ; materials - International Standards general,... Before and after tests steel 316/304 vs 316L/304L ; materials - International erosion corrosion in stainless steel pipe to it.