erosion corrosion in stainless steel pipe  

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

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