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Corrosion
Brian Dalder, engineering consultant, Eli Lilly
Brian Dalder is an engineering consultant at Eli Lilly and Company, Lafayette, Indiana and a registered professional engineer. He has almost 28 years of experience with the company, covering many aspects of bulk chemical manufacturing, including process automation, process development and scale-up, and process engineering. He now is the material selection and corrosion expert for the firm and heads its Materials Compatibility Lab. He has developed several internal material awareness and material training courses and currently teaches these several times each year. 
Is 304 stainless steel pipe suitable for handling nitric acid?
Is 304 stainless steel pipe suitable for handling nitric acid (10% to 30% concentration) for a continuous duty application?
Category: Corrosion
Which is a better MOC for carbon black plants?
Which is a better MOC for carbon black plants? We crack heavy oils (with sulfur content) at 800 degrees C to produce carbon black. Is 304 better or 316 better to avoid acid corrosion in our pipelines?
Category: Corrosion
Is it better to use a Hastelloy C alloy or 316L stainless steel?
We need to install a level switch probe in 98% sulfuric acid. Based on corrosion resistance, would it be better to use a Hastelloy C alloy or should we use 316L stainless steel? The storage tank temperature is 70 to 90 degrees F and there is no contamination of the acid.
Category: Corrosion
Do austenitic stainless steels have good resistance to carbonic acid attack?
We have a fin-tube style heat exchanger in which we mix natural gas and liquid water, and use an exhaust gas stream to vaporize the water and preheat the fuel mixture. We have a new water recovery process in which we condense the water out of a carbon dioxide rich exhaust stream and feed this into the heat exchanger. It has been observed that the recovered water is slightly acidic at a pH 4.5, and it has been attribute to the presence of dissolved carbonic acid in the water. The tubes of the heat exchanger are 304H Stainless Steel. Is corrosion something we should be concerned about for the long term operation of this unit?
Category: Corrosion
Is 904L stainless steel suitable for a fluid with 80% hydrogen sulfide?
Is 904L stainless steel suitable for a fluid with 80% hydrogen sulfide? What is the best pipe material for fluids that contain 80% hydrogen sulfide?
Category: Corrosion
Are there any chemical additives that can be applied to 304 stainless sheets to prevent corrosion?
I need to install 304 stainless steel sheets to a water pool base. How can I prevent or control the corrosion by the water? Are there any chemical additives that can be applied to 304 stainless sheets to prevent corrosion?
Category: Corrosion
What material is suitable for hydrogen gas?
Would like to know what is material suitable for hydrogen gas with an operating/design pressure of 21/27.53 kg/cm2 (g) and operating/design temperature of 25/60 degrees C.
Category: Corrosion
What metal materials of construction are good with 98% Sulfuric Acid?
Please confirm what metal materials of construction are good to be in contact with 98% Sulfuric Acid at 85 degrees F and 1-3 psig?
Category: Corrosion
Will operating at elevated temperature lower the recommended maximum working pressure?
Can a CPVC 3-inch SCH 80 370 psi at 73 degrees F line handle 85 degrees C at 100 psi?
Category: Corrosion
What are important soil characteristics for determining corrosivity?
What are the parameters to be tested as part of soil chemical tests for steel, ductile iron and GRP pipes for corrosion protection?
Category: Corrosion
Can you define salinity in practical terms?
I am a mechanical engineer and am currently working on a project where I need to understand the salinity as chlorides in the water. It is measured in mg/l, but I can't picture if this is corrosive or not? Is my understanding correct in that for arguments sake if I have 1500 mg/l salinity as chlorides I essentially have 1.5 g of salt for every 1 liter of water? Therefore, depending on densities, that's approximately 1.5 g per 1 kg - am I correct? My next question, would this be highly corrosive to the likes of carbon steel pipes? I try to equate everything I do to practical examples - such as a normal hit with a sledge hammer equates to about a ton of force, give or take, therefore if I need to know quickly if a structure can withstand some force I use this test to gauge it quickly. Are you able to give me an example of salinity as chlorides and how corrosive they can be to carbon steel so I can gauge this quickly just by looking at the number and then I can investigate further if needed or not worry about at all. Sorry to go on a bit, but your help would be very much appreciated.
Category: Corrosion
Do I have worry about corrosion in this reactor?
I have a 316 stainless steel reactor. This reactor contains magnesium chloride (MgCl2) solution and a natural gas such as ethane or propane. Our temperature range is 15 to 68 degrees F. Pressure range is 20 to 150 bar. And maximum concentration of MgCl2 is 10% by weight. Our work is sensitive to impurities. Do I have worry about corrosion in this reactor?
Category: Corrosion
What are commonly used MOCs for phosphoric acid service?
What material of construction (MOC) is recommended for bolt and nuts used for connecting two HDPE pipes used for transferring phosphoric acid? What MOC is suitable for pumps, flanges, footvalves, and valves used for transferring phosphoric acid?
Category: Corrosion
What is the proper material for a batch reactor running a Mannich reaction?
I want to know what's the proper material for a batch reactor in which nitropropane and formaldehyde and morpholine react.
Category: Corrosion
What is the compatibility of sulfuryl chloride with a glass lined reactor?
What is the compatibility of sulfuryl chloride with a glass lined reactor?
Category: Corrosion
Which material is suitable for molten sulfur?
Which material (SS304/316) is suitable for molten sulfur at 120 to 130 degrees C?
Category: Corrosion
Can we estimate the corrosion rate with cathodic/anodic protection systems?
Our biodiesel process has seen a recent introduction of sulfuric acid. We would like to use the existing 316 SS piping for six to eight months with anodic or cathodic protection. The biodiesel runs at 120 Celsius and will have 0.2% to 3% sulfuric acid. Can we estimate the corrosion rate and/or protect?
Category: Corrosion
Can you help with corrosion caused by chlorinated water?
What is the limit of Cl2 and Cl- in process water used in a fermentation process at both process and corrosion point of views? Generally speaking, I would like to know what range of Cl2 and Cl- is permitted to prevent corrosion in 304 stainless steel fermenters and to avoid the yeast degradation in a baker yeast production plant.
Category: Corrosion
What piping material is suitable for caustic scenarios?
What piping material is suitable for 5% NaOH with an operating condition of 80 degrees Celsius and 4 bar?
Category: Corrosion
Is SS316 suitable for use in urea solution piping?
Is SS316 suitable for use in urea solution piping? We want to use SS316 instead SS304 for urea solution piping service.
Category: Corrosion
What material would be good for an ammonium persulfate acid etch tank?
Would a 304 stainless tank be a good choice for an ammonium persulfate acid etch tank at a concentration of 10% by weight, mixed with deionized water, total fill of 125 gallons, not bubbled or agitated and at ambient temp? Or would 316 be needed? Or do I need to go to a plastic tank? This tank would also need a containment tank. The rest of the line would have a deionized water rinse station, a sodium bicarbonate solution station and finish off with a hot deionized water rinse station (190 °F).
Category: Corrosion
Could you recommend inhibitors to prevent chloride attack on stainless steels?
Could you recommend inhibitors to prevent chloride attack on stainless steels?
Category: Corrosion
Can we use a 316SS pump?
For an effluent having approximately 500 ppm chlorides, can we use a pump made of 316 stainless steel?
Category: Corrosion
Is Duplex Alloy 2507 a good choice?
We selected duplex stainless steel type SAF2507 for heat exchanger tubes to resist stress corrosion cracking (SCC) in the third stage of a carbon dioxide compressor. Tube side is high conductivity (5,000 ppm) cooling water while shell side is carbon dioxide gas and the expectation is at shutdown carbon dioxide will be converted to carbonic acid. Is our selection SAF2507 correct?
Category: Corrosion
Will weld joints be stress relieved?
When carbon steel and low alloy steel are used to handle corrosive or mildly corrosive fluids, will weld joints be stress relieved?
Category: Corrosion
How do you apply a rubber lining to a perforated carbon steel plate?
I need to know how to apply a rubber lining to a perforated carbon steel plate that's located inside and in the bottom of a pressure vessel (150 psi max, with NaOH). I need a description to understand the process of rubber lining in this particular location (perforated carbon steel plate) and have a warranty that this lining is going to last for a "X" amount of time.
Category: Corrosion
Can I safely use a cutting torch on a stainless steel vessel containing traces of aluminum sulfate solution?
Can I safely use a cutting torch on a stainless steel vessel containing traces of aluminum sulfate solution? Am I likely to generate hydrogen during the cutting process?
Category: Corrosion
Does 904L stainless steel stand up to 32% HCl?
Does 904L stainless steel stand up to 32% HCl? If not, what material do you suggest?
Category: Corrosion
Can you help with underground piping questions?
For our underground piping, we are told to install a cathodic protection system with an external coating. The piping is electrically isolated by installing the insulating flanges at the ends. However, the liquid in the pipeline is phosphoric acid, an electrically conductive liquid. Does it require electrical isolation in the internal surface also? If so, how is this done?
Category: Corrosion
Which stainless steel would resist ammonia or carbon dioxide corrosion?
Which type of stainless steel would be suitable for tubes to be placed in an industrial cooling system that works with CO2 and ammonia fluids and the max pressure is 45 bar? The stainless steel tubes will replace copper tubes.
Category: Corrosion
Is galvanized steel suitable for long-term applications?
Which material should I use, galvanized steel or SS316 (higher cost), for an area in a petrochemical plant in which less than 10ppm of H2S in the air are present? Specifically, for long term, is galvanized steel is suitable?
Category: Corrosion
What stainless steel material would be suitable for sulfuric acid?
What stainless steel material would be suitable for a burner tube in a 14% sulfuric acid wash at 140 deg F?
Category: Corrosion
What's the best material for a sulfuric acid piping system?
We are designing a sulfuric acid piping system from ships (wharf) to a fertilizer industry; this piping will be about 4 km long and 10 inches-diameter; sulfuric acid is 94-96% concentrated at 45 °C. Which is the most indicated material for the piping: 316L, 304 or 904?
Category: Corrosion
If I have a stainless steel bolt and combined it with a silicon bronze nut, would I introduce rust?
If I have a stainless steel bolt and combined it with a silicon bronze nut, would I introduce rust? Cleaning agents used to clean daily are hypochloride.
Category: Corrosion
Why don't mixtures have the same corrosivity as their components?
Recently, I observed that a mixture of acetonitrile and thionyl chloride at 30 - 100 deg C is highly corrosive to hastelloy C-22 though individual components are indicated to be almost non-corrosive. Please let me have your opinion on the above observation and also alternate solutions for handling such a mixture.
Category: Corrosion
What's the best alloy for sulfuric acid?
Can you tell me what alloy would be best in a service with 10% sulfuric acid at 140 degrees F?
Category: Corrosion
What is the best suitable pipe material of construction for sesquisulfate?
What is the best suitable pipe material of construction for sesquisulfate?
Category: Corrosion
Is 13% Chromium suitable for valve trim in HCl service?
Is 13% Chromium suitable for valve trim in HCl service?
Category: Corrosion
What material would work best for 98% Sulfuric acid transfer piping/fittings?
What material would work best for 98% Sulfuric acid transfer piping/fittings? Temperature at time of transfer should be Hawaii ambient, which is between 81-90 degrees F. Is there a plastic that can be used or would steel be the safest option?
Category: Corrosion
Will descaling with HCl acid cause corrosion?
We have done descaling of heat (tube in tube) exchangers used for processing fruit pulp with a commercial chemical (known as "PICLEWELD" ) made up of HCl acid (17%), nitric acid (2%), corrosion inhibitor (30%) and the remainder water. After passing this chemical through the heat exchangers at ambient temperature for 3 hours, the liquid is drained out from the system and left like this for 24 hours before passing passivation chemical into the system and heat exchangers. Will the residual (remnants of descaling chemical) liquid in the tubes (which are placed horizontally) cause any corrosive or pitting action which can lead to pin holes? Tube wall thickness is 4 mm.
Category: Corrosion
Can you laser weld silicone tubing to silicone tubing?
Is it possible to laser weld silicone tubing to silicone tubing? If so, how?
Category: Corrosion
Which pump head materials will last longer?
I am selecting pump head materials for a reverse-osmosis system that will pump room temperature sea water at 800 psi. After duty cycles of 3 hours the system will always be flushed with fresh product water until the next weekly cycle. Due to cost considerations my choices are brass and nickel-plated cast iron. Which will last longer?
Category: Corrosion
How much corrosion resistance do I need to consider?
If the content of a reactor (packed bed column) is palm oil, the body of the vessel is 304 stainless steel, how much corrosion resistance do I need to consider? The working pressure is -1bar (vacuum) and working temperature is 70 degrees C.
Category: Corrosion
Would welds be in jeopardy in the presence of a dual-wire feed?
Does dual wire feed (85% Zinc; 15% Aluminum) metalizing inside an oil tank or vessel create hydrogen as it sacrifices itself in preference to the steel? And, if so, would that hydrogen, in the presence of sulfur, embrittle welds? I believe the answer is no, but I have an engineer who is concerned.
Category: Corrosion
Can you store cooling tower and boiler blowdown in a painted carbon-steel tank?
Is it OK to store cooling tower and boiler blowdown along with RO rejects in a painted carbon-,steel tank? The water is very high in TDS/conductivity.
Category: Corrosion
What is the best material of construction for hazardous chemicals?
For the production of aluminum sulfate solution, what is the best material of construction for the agitated mixing reactor, which will contain aluminum trihydrate (or bauxite), sulfuric acid, and water? Would it depend on the order of addition of the reactants? Brick-lined, glass-lined, and lead-lined reactors might be good for acid and water solutions before the addition of the aluminum hydrate (due to the corrosivity of the weak sulfuric acid). However, can a 316SS reactor be safely used if acid is added to a hydrate/water solution without corrosion to the tank?
Category: Corrosion
How much longer would 316 stainless steel bolts last versus 18-8s?
Our welder tacked on SS 18-8 bolts to a plate instead of 316 bolts. Process fluid drinking water quality with low chlorines and chlorides <500 ppm at temperature below 40 Celsius. How long will it take to see brown staining around the fasteners How much longer do you think the 316 bolts would last versus 18-8 fasteners
Category: Corrosion
How do you select between different grades of the same material?
Design conditions are 950 degrees F at 320 psig. Service is extraction steam. Pipe material is A335 P-11; why not P-21, P-22 (grades)? What are the basic steps for selection between different grades of the same material?
Category: Corrosion
What welding rod materials will resist chloride stress cracking?
I'm having a shell and tube heat exchanger fabricated from 316L stainless steel seamless tubes and 316L stainless steel tube sheets. Steam at 100 to 150 psig will be on the shell side and a soap solution containing 21% to 33% water, 1.2% NaCl, and 1% to 5% free fatty acid at 150 to 175 degrees C will be boiling in the tubes. Can you please tell me if there is any special welding that should be done where the tubes connect to the tubesheets to provide greater resistance to chloride stress cracking. Are there any special welding rod materials that are recommended for making the welds more resistant to chloride stress cracking?
Category: Corrosion
What effect do different acids have on stainless steel?
What effect does nitric, sulfuric and/or hydrochloric acid have on type 304 and 316 stainless steel?
Category: Corrosion
What materials are suitable for transporting petrochemicals products in a pipeline?
Which materials could be used in a pipeline to transport the following petrochemicals products: 100% paraxylene, 100% ethylene glycol and 100% methylene diphenyl diisocyanate? Our first choice is carbon steel pipes according to API 5L. Is it suitable?
Category: Corrosion
What are the steps for selection among different grades of the same material?
Design conditions are 950° F at 320 psig. Service is extraction steam. Pipe material is A335 P-11. Why not P-21, P-22 (grades)? What are the basic steps for selection among different grades of the same material?
Category: Corrosion
What are the corrosive effects of propylene glycol?
I'm having an issue finding reliable information on the corrosive effects of propylene glycol when in contact with various types of stainless steel. In an "intermittent spray" application in atmospheric temperatures and pressures and glycol/water concentrations of 50-90% glycol is there a reasonable danger of corrosion of 300 series and duplex stainless steels? If so, can you recommend any reference material that can be cited describing what precautions would mitigate the issue, etc.?
Category: Corrosion
What material is suited for a dichlorobenzene distillation tower?
We have a condenser in a DCB (dichlorobenzene) distillation tower. The MOC is carbon steel. After two months of running the plant, we are faced with corrosion. Can we use some other material? The temperature is 85° C.
Category: Corrosion
Is a corrosion allowance required for internally coated tanks?
Is a corrosion allowance required for internally coated tanks?
Category: Corrosion
What MOC is suitable for running reactions containing 5% hydrochloric acid?
I would like to react sorbitol (sugar alcohol) with HCl 5% in a reactor under the following conditions:
- Temperature = 140 - 160 °C
- Retention time = 30 - 40 minutes
- pH actual mixed raw material = 0.4 - 0.5
- Conductivity mixed raw material = 220 ms/cm
Category: Corrosion
Is it feasible to use carbon steel with some rubber or Teflon lining?
What should be the possible metallurgy for sulfuric acid of concentration higher that 98%? Keeping in mind the higher metallurgy, is it feasible to use carbon steel with some rubber or Teflon lining?
Category: Corrosion
How can I prevent stress corrosion cracking?
I have a 3-inch schedule 40 carbon steel line carrying caustic 50% getting in service for about 6 months. Repeated cracks in different welds and HAZ has occurred. This should be caustic embrittlement. What is the best action to avoid facing this problem in other welds in this line considering that there are always some parts of the line suffering general corrosion?
Category: Corrosion
What chemicals increase corrosion of 304 stainless steel?
I am looking to put in two fixed 304 stainless steel ladders into a water treatment plant flocculator. I am unsure of what chemicals are "notorious" for increasing the corrosion of 304 stainless steel. The chemicals in the flocculator water are potassium permanganate, powdered activated carbon, aluminum sulphate, calcium hydroxide, polyaluminum chloride and the pH hovers around 11.5-12 (quite high). So will a 304 stainless steel ladder be corrosion resistant enough for that environment? Also is a lower pH, around 3-5 not sure what chemicals are causing it, hard on 304?
Category: Corrosion
What is the best coating for a carbon steel tank that holds sodium hydroxide?
What is the best coating for a carbon steel tank that will contain 50% sodium hydroxide? In Cartagena - Colombia, HR = 82%, ambient temperature = 30 degrees C and the tank is supported by an asphaltic base. Would be necessary to have cathodic protection system?
Category: Corrosion
How can I find an appropriate material of construction at a cost I can afford?
Regarding a previous Ask the Expert Q & A: What is a suitable coating or a MOC that can stand HF at 100 degrees C?
Additional details about HF:
- Concentration: 60%
- Composition: 15%
- Operating temperature as I said before is around 100 deg C.
- Current MOC of the vessel is SS316 ti.
Referring to the suggestion of Hastelloy C-276, on the same lines, I have come to know that Hastelloy C 2000 has comparatively better properties. But the main problem would be cost optimization, since the cost of the material, fabrication, installation costs, etc. would be too high. On coating materials, I have read on the DuPont website on the seemingly excellent mechanical and chemical properties of ETFE or commonly known by its trade name Tefzel, though I am not sure about its successful contribution in this scenario.
Category: Corrosion
What is the permissible level of minerals in cooling water?
I have river water with the following characteristics: pH: 7.5; EC: 180 micromhos/cm; Total solid: 0.060%; K: 6.31 ppm; Ca: 38.46 ppm; Mn: 0.23 ppm; Fe: 5.79ppm; Zn: 0.09 ppm and Sr: 0.08 ppm.
Can you suggest whether this water is suitable to use in cooling pipe for power reactor? Or will it need treatment? Can you suggest what is the permissible limit of elemental concentration in cooling water to be used in cooling pipe in a power reactor?
Category: Corrosion
Galvanized steel may not be the best material of construction
We currently have a closed water system that feeds two white-metal bearings and a two labyrinth seal on a gas booster fan. The water is currently held in a galvanized steel tank and during the winter months we have put ethylene glycol (antifreeze) into the water to make a water glycol mix to stop the water freezing up as this is a vital part of the operating plant. We have been experiencing problems with the galvanized steel tank corroding and I personally have found out that the glycol reacts with the zinc coating of the galvanized steel. However, I don't know the actual reason why the reaction takes place. This is needed as I have the task of redesigning the water system.
Category: Corrosion
What is a suitable coating or a MOC that can stand HF at 100 degrees C?
We are using a reaction vessel that is constructed of SS316ti and this operated at a temperature range of around 90 - 100 degrees C. Corrosive materials like HF and chromic acid are used in the manufacture of the product. In August, the vessel thickness reduced by 1 mm, for which HF was assumed to be the main culprit. A decision was made to provide a coating so that the vessel operation can be resumed as soon as possible. A probable alternative, though not preferred, was to replace the vessel entirely with a vessel having a material of construction (MOC) that can tolerate HF, of which there is very little information available to us. So please suggest a suitable coating or a MOC that can stand HF at 100 deg C.
Category: Corrosion
How to avoid the formation of rust colored pit marks and keep your Teflon coating in place
What coating material can be applied to 316 stainless steel equipment (switchboards, external portion of reactors, etc.) to avoid the formation of rust colored pit marks?
Another question: We have a Rotomac Vacuum Drier (RVD) made of SS-316, that moves hot water (80 - 90 degree C & 720 to 760 mm/Hg vacuum application) within its outer jacket. Wet cake of Glucosamine HCl is kept inside the RVD along with 5% ethanol to dry. Vapor temperature inside RVD is up to 60 degree C. Ph=1. The RVD internal Teflon coating has peeled off in 1 year. Would an internal coating of polystyrene for the RVD be more successful than that of Teflon since it would be more economical?
Category: Corrosion
Can you recommend the proper materials of construction for storage tanks?
We are redesigning two sulfuric acid (75%) storage tanks and three oleum storage tanks. We would appreciate your help with information regarding materials of construction and also on the kind of piping, valves, etc., more appropriate for these services. Also if you could direct us to different providers who have experience with these products.
Category: Corrosion
Why is there corrosion damage at the weld and HAZ areas?
We are using sulfuric acid to maintain the pH of cooling water at our plant. We are experiencing severe damage to the SS-316 material piping at the outlet of the sulfuric acid storage vessel. The damage is pronounced at the weld and at the HAZ area. My question: Why are welds and HAZ areas specifically targeted? My second question is based on the finding that when the damaged spool of pipe was cut in half, a continuous ferrous sulfate (brown colored) acid level line was observed just above the centerline of the pipe. The extent of damage was far worse above this line in the horizontal portion. However the damage to the vertical weld joint is uniform throughout the circumference. Wow is this failure phenomenon explained?
Category: Corrosion
Can I use Inconel 625 to transport sulfuric acid?
Can I use Inconel 625 to transport sulfuric acid (concentration from 94% to 96%)? The intention is to use Inconel 625 alloy as a clad overlay in valves and flanges.
Category: Corrosion
Do I have to worry about chloride-induced corrosion of 316 stainless steel?
Our client has a pump station that will primarily be pumping water at pressures around 1,000 psi. However, at certain times it may be subjected to a highly corrosive water that may have chlorides over 150,000 mg/L and TDS > 275,000 mg/L. pH around 6.3. Total acidity = 390 mg/L, total alkalinity = 40 mg/L. Sulfate = 150 mg/L. Temperature ranges between 37 deg F and 68 deg F. It is anticipated that the water line could see the corrosive water for a period of 3-7 days at a time and would then convert back to seeing surface water. There are quite a few valves on this line and we are looking at both 316SS and super duplex valve bodies. Since cost is an issue for our client, is it possible to use the 316SS valves and then rinse the line using surface water? Or will we definitely need to upgrade to a super duplex-type material? Also, for some of the piping, it was originally specified as carbon steel (at the station). In lieu of replacing that piping with FRP, could the carbon steel be coated with something for corrosion resistance?
Category: Corrosion
Will copper cause a problem in our cryogenic application?
We have used SS304 material in the cryogenic separation systems especially as SS304 is considered a good material even below 20 K temperature. However, we are seeing some amount of copper (up to 1%) in SS304. Is there a problem due to the high/unspecified copper content in SS304 for cryogenic application?
Category: Corrosion
Is stress corrosion cracking the cause of leaks?
We have installed U-Tubes of SS-304 material in our gas water cooler. The heat exchanger was put into service in 2009 at our ammonia plant.
Service Condition Of Exchanger:
- Fluid: Process Gas
- Composition: Hydrogen 44%, Nitrogen 15.5%, CH4 18.4%, NH3 18%, Argon 3.7%
- Shell Side is Cooling Water.
My questions are: 1. What will be the effect of 18% ammonia in process gas on the SS-304 tube having 1% copper? 2. What is the effect of 1% Cu on SS-304 material while annealing process during U-Bends stress relieving? 3. Is there any kind of leeching phenomena associated with the presence of copper in SS-304 material?
Category: Corrosion
Is there a reason to require L grade material from a safety or reliability standpoint for a flanged valve?
I have a customer that is using 316L and 304L flanged valves in the process piping process. These are much longer lead times and specially manufactured and as a result much more expensive. I understand the benefit when welding is involved but is there a reason to require L grade material from a safety or reliability standpoint for a flanged valve? The plant is a nitrogen facility.
Category: Corrosion
Can SS316 be used in lieu of SS316L?
I want to verify that for Offshore Platforms Equipment support bolts. Can SS316 be used in lieu of SS316L?
Category: Corrosion
Can you suggest the material of construction for a sulfur storage tank?
Can you suggest the material of construction for plate (shell/roof/bottom) to be used for sulfur storage tank?
Category: Corrosion
How do I prevent molten salt corrosion?
I have a molten salt bath (NaCl, CaCl, MgCl) at temperature of 700 degrees C. I need to design a probe that will not corrode in air when removed from the bath.
Category: Corrosion
Is it normal to have elements in an alloy that are not listed in the specs?
We have to use SS-304 seamless pipes for liquid ammonia at 20 kg pressure. We have gotten spectral analysis of SS-304 pipes. Besides the components as mentioned in ASTM standard, we have found copper content to the tune of 0.50% to 0.96% in different samples. We want to confirm whether we can use these pipes for liquid ammonia application where the ASTM Standard does not mention copper content in SS-304.
Category: Corrosion
Do I need to consider corrosion allowance for austenitic stainless steels?
In one boiler we use a stainless steel 309 belt to keep the U-tube in a linear position. The SS 309 is exposed to 1134 ppm sulfur dioxide at 700-800 degrees C continually. Do I need to consider any corrosion allowance in the design or change the material?
Category: Corrosion
What is an acceptable clear sight-glass material for a sulfuric acid tank?
What is an acceptable clear sight-glass material for a sulfuric acid tank (~98% concentration)?
Category: Corrosion
What is the best tube and tube sheet material for a heat exchanger?
What is the best tube and tube sheet material for a heat exchanger where the water is provided by the client and has a chlorine content up to 480 mg/L? I used SS304 tubesheet and A516 Gr.70 tubesheet material, but heavy leakages are taking place at the site.
Category: Corrosion
How much chlorine can stainless steel withstand?
What should be the maximum allowable level of free chlorine for potable water pipe lines made of SS304?
Category: Corrosion
How do we prevent damage from sulfuric acid to the rubber lining?
Very frequently our sulfuric acid dilution (25% concentration) tank with rubber lining is damaged. Kindly provide a solution to this problem to avoid frequent maintenance.
Category: Corrosion
What is the effect of HCl on SS316?
What is the effect of HCl on SS316? What is the maximum concentration of HCl it can withstand?
Category: Corrosion
What is the best material of construction for transfer piping?
We have a plant that produces fertilizer. In one section we mix 40% phosphoric acid and 98% sulfuric acid together in a ratio of 75-80 : 25-20 phosphoric acid:sulfuric acid. After that the mixture is cooled to a temperature of 80 degrees C. What is the best material of construction for transfer piping? The existing material, 304 stainless steel, shows problems at the welds.
Category: Corrosion
What pipeline material is suitable for transporting corrosive materials?
Which materials could be used in a pipeline to transport the following products: acetic acid 100%, formic acid 85%, and formaldehyde 37%? Our first choice is 316 stainless steel. Is it suitable?
Category: Corrosion
Is it a common practice to apply chromium plating to a duplex stainless steel?
Recently one vendor performed a minor repair (smooth grinding) of an impeller (bump) which is made of a duplex stainless steel. After the repair was done, a chromium plating was applied by the vendor to restore the repaired area. The operating condition of this bump is in an environment of 3000 ppm chlorides at 170 degrees F. I would like to know what is your opinion about this restoration in this environment?
Category: Corrosion
What do you recommend to protect against corrosion?
We have a fabricated structure that is machined after stress relieving and painting. The machining is carried out to maintain dimension and attaching other accessories. What is the recommended surface protection to be provided at the machined surface: (1) give a primer paint coat or, (2) give a rust preventive oil coat. The material used is to specification JIS G3114 atmospheric corrosion resistant steel, which is normally used in rail applications.
Category: Corrosion
How do you remove rust and prevent its reformation?
Pressure vessels (MOC:CS) are showing rust deposits inside. It is understood that water ingress or moist air could be the reasons to cause electrochemical reactions and that resulted in the formation of hydrated iron compounds. My question is how to clean the rust and its further prevention. Kindly suggest standard methodology to remove rust, any NDT checks required thereafter and how to prevent its reformation.
Category: Corrosion
Carbon steel and stainless steel will be in contact. How do I avoid corrosion?
I want to fabricate a SS316L tank, but legs and supports are to be made of carbon steel. What kind of painting shall I provide for carbon steel as it will be in contact with stainless steel and I would like to avoid any corrosion. Is the below painting specs OK?
2 coats
110 µm
Sweep blasting, which in any case shall be carried out with abrasive free of any iron or ferrous components.
One priming coat of a two-pack epoxy-based paint, with zinc phosphate corrosion inhibitor
NDFT: 60 µm
One final coat of polyurethane paint, modified so that it may be easily recovered by itself.
NDFT: 50 µm., Finish: glossy
Category: Corrosion
Regarding gas turbines, when is the corrosion rate worse?
In our platform we have three gas turbines to generate electrical power. The fuel for these turbines is supplied from well gas. The gas is sour and wet with the temperature near the dew point. The question is when is the corrosion rate worse, when the gas is heated a little with an electrical heater above its dew point to avoid hydration and a corrosive environment, or when wet gas is not heated even though we know that hydrate is forming in the lines.
Category: Corrosion
Will salt break down concrete?
We had a concrete ramp laid for a client 16 months ago. There has been no problem to date but the last few weeks they have been putting table salt on the concrete steps. This has broken up the surface. I have not seen this before. The unaffected concrete is rock hard to the areas where the salt has been. My question is will table salt in reasonable accumulation break down the surface on the edges and top of the concrete?
Category: Corrosion
How do I prevent corrosion on a copper coil?
I want to use a copper hot water coil in a furnace that burns anthracite coal. What would you suggest I coat/plate the copper coil with to prevent corrosion from the sulfur and other combustion gases?
Category: Corrosion
What is the best material of construction for chlorinated water?
What is the best material of construction for chlorinated water (300PPM & 15PPM) -- SS316L or duplex?
Category: Corrosion
Is there a safe chloride content level in regard to SS316L?
What is maximum chloride content that can allow for SS316L? What is corrosion allowance of SS316L?
Category: Corrosion
What material is suitable for a mixer that blends sodium sulfate?
We are currently using an ordinary concrete mixer to blend a mixture sodium sulfate (95%) and some other chemicals (5%) in a humid environment. The problem we encounter is rusting and corrosion of the mixer. The rust also contaminates the mixture. Now we are considering building our own mixer, what material is suitable to build the mixer? Is SS316L/SS034L suitable? Is it possible to install a sacrificial anode or impressed current cathodic protection if we purchase a new concrete mixer for our service instead of constructing one ourselves?
Category: Corrosion
Can SS316 material be used for amine and hydrogen sulfide service?
Can SS316 material be used for amine and hydrogen sulfide service?
Category: Corrosion
How does elemental sulfur form in a water system?
In our Flare Gas Recovery Unit, the liquid ring compressors suction check valve and coolers shell tubes side (cone seal water) get covered with deposits that contain 95%wt elemental sulfur plus iron and carbon. Our question is: How elemental sulfur forms from H2S or other sulfur compounds in this water system? I have always heard that elemental sulfur indicates that oxygen was present. I have no independent basis to know whether this is true. Assuming that it is true, then logic would suggest that there must have been some H2S or a similar compound present along with oxygen (in the water that was non-de-aerated, so I suppose that water could have been a source of oxygen). The refinery flare gases contain some H2S, and some minor amount of oxygen. Initially we used to use reject water from an RO unit as the main water source. That water is no longer used, since it has been change to Stripped Sour water. Water system pH is controlled between 7.3 and 8.3.
Category: Corrosion
What’s the best material for a NaOH reactor?
What would be the best material to construct a reactor of where the chemical used for reaction is NaOH at 50% concentration and temperature is up to 90° C?
Category: Corrosion
How can we stop salt from corroding concrete structures?
We are the manufacturer of table salt (sodium chloride) from raw salt collected from the evaporation pans and subsequently it is processed through water wash, decantation, centrifuged and then sieved through required size and packed with addition of iodine and sold in various pouches/bags. The handling of salt in wet areas has created havoc on the concrete structure and eaten away the rebars and also percolated through floors, beams and columns. May we ask you to suggest the best remedial measures like rehabilitation by either cathodic protection, inhibitor addition in cement mix, alkalization, chloride removal by electrochemical method etc.?
Category: Corrosion
Will SiO2 React With Sulfur Gas?
Can SiO2, as a refractory' ingredients which was used to lining inside a conversion reactor, react with SO2 and SO3 gasses inside reactor? My customer claimed that SiO2 will react with sulfur gas and then corrode their S304 steel, which was used to construct their reactor. As much as I knew, SiO2 can only be used as catalyst or capture sulfur gas in other process but it does not react with sulfur gas to produce any corroding substance.
Category: Corrosion
What would be the ideal material of construction for a hydrochloric acid plant?
What would be the ideal material of construction for a hydrochloric acid plant? Would you recommend using galvanized steel, which is painted with three layers ( two epoxy + one final coat of acrylic), the total thickness is maxi 180 μm?
Category: Corrosion
Can I replace stainless steel with nickel-plated brass?
How resistant is stainless steel 304 and 316 to carbonic acid (H2CO3)? Can I replace stainless steel with nickel-plated brass for economical reasons?
Category: Corrosion
Can you suggest a corrosion-resistant material?
I have a large storage tank of 93% sulfuric acid. I am having excessive corrosion of the top of the 4-inch carbon steel outlet pipe. I am thinking of replacing the outlet pipe with Schedule 120 carbon steel pipe. Is there any more resistant material, insert, or coating you could recommend for increased life?
Category: Corrosion
What is the pH range for 316L stainless steel?
My company deals with submersible electric motors used to drive pumps in various fluids. Water systems are the most common that we deal with. The question is what is the pH range that 316L stainless steel can handle? The temperature of the water does not exceed 25°C. It can flow past the motor anywhere from 0.5 ft/sec to 10 ft/sec when running, to no water movement when the system is turned off. pH seems to be the only thing I cannot find good information on how it affects 316L.
Category: Corrosion
What is the best material of construction for a non-return valve?
We have a non-return valve/check valve installed in a discharge pump piping made of Alloy 20. The liquid that is being pumped is spin bath liquid with H2SO4=125 gms/liter, Na2SO4=380 gms/ liter, and ZnSO4= 16 gms/liter and a temperature of about 50° C. Based on our experience, the worst corrosion is in the non-return valve and we are getting about two to three years of service. What is the best material of construction for this service?
Category: Corrosion
Are there materials of construction suitable for spin casting?
I am looking for a material of construction suitable for an industrial decanter centrifuge. The feed contains mixed sulfate and chloride crystals in a solution containing 2% free HCl. Operating temperature would be about 80° C. Ideal material would be corrosion and abrasion resistant, with high structural strength (to withstand about 3000 g). It must also be possible to spin cast the material.
Category: Corrosion
What is the maximum chloride content allowable before the heating medium needs to be replaced?
We have a heating medium system where a circulating stream of 20% TEG is heated up to approximately 150°C by the exhaust from a power generator. The piping in the system is carbon steel. The pH is 9.5 to 10 and the oxygen level is approximately 1 mg/l. Leaks in the system can introduce chloride into the heating medium. What kind of maximum chloride content should we allow, before we replace the heating medium, in order to avoid corrosion?
Category: Corrosion
What material is best for lime milk tanks?
I am fabricating a lime milk tank. The shell/cone/roof is designed with SS316L material. The leg support is designed with SA-36/S 275 JR. This is done to reduce the overall cost without comprising on quality. I want to know if my design is OK? Or should I go for SS316L material for the supporting legs also? These legs are very expensive in SS316L material.
Category: Corrosion
Corrosion of Metals in Sulfuric Acid
We thank you for the answer concerning the corrosion effect of 20% sulfuric acid on SS316L (http://www.chemicalprocessing.com/experts/answers/2009/070.html). It is difficult for us to locate alloy 20 just a few plates to be used in fabrication work as raw material from the commercial market. Only SS316L is available. If recommended thickness is 8mm but if we go in for 10 mm keeping in view the rate of corrosion over a period of time, will this work? What is the approximate time frame anticipated and can the tank last for about 15 years while sustaining the corrosion effect during this time period?
Category: Corrosion
What is the best material for corrosive contents?
We want to fabricate and install 40m3 capacity electrolyte storage tanks carrying sulfuric acid of 20% concentration. The plant under installation is importing machinery for a battery crushing process. Please advise what will be the best metal to use for fabrication of tanks that will be filled with a corrosive medium and the plant by itself is considered as an environmental hazard.
Category: Corrosion
Do I need to consider corrosion allowance?
I am fabricating a SS 316L tank of 6mm shell thickness for storage of lime milk. I want to know if I need to consider any corrosion allowance (say 1.5mm) in the design.
Category: Corrosion
What materials of construction are suitable to handle the calcining of inorganic phosphorus compounds?
What materials of construction are suitable to handle the calcining of inorganic phosphorus compounds? Some phosphoric acid is also present. Temperatures are up to 500° F. Also have a process for 1300° F.
Category: Corrosion
Is it true that titanium is a non-corrosive material?
I am working for a copper refinery. We have a 17-cubic-meter capacity reactor that is made of titanium (inside) and carbon steel (outside) with the shaft and impeller also made of titanium. Is it true that titanium is a non-corrosive material? We are always having problems with corrosion of titanium bolts and vessel corrosion. Also, for sulfuric acid applications, which metal would be preferable: 316L stainless steel or 904L?
Category: Corrosion
Have you heard of the corrosion process called 'chelation'?
There is a corrosion process, about which very little is written, called "chelation." We are a valve manufacturer and have found that amine containing processes and ammonia can cause significant corrosion on cobalt-based hardfacing materials such as Stellite 6. Are you aware of any papers or books that may address this issue?
Category: Corrosion
If we use a carbon steel tank for storage of amine, will the tank be corroded?
As you know, in gas refineries amine is used for elimination of carbon dioxide and hydrogen sulfide raw gas. My question: If we use a carbon steel tank for storage of amine, will the tank be corroded?
Category: Corrosion
Selecting Materials of Construction For Sulfuric Acid Service
Please suggest a material for 5% H2SO4 storage. Operating temperature = 30 to 50 degrees C. Is the use of FRP OK? Also, what are your suggestions for the use of CS-lined storage tanks with linings like lead and PTFE?
Category: Corrosion
Corrosion Resistance of Carbon Steel to Ethylene Dichloride
At what pH would you keep a mixture of ethylene dichloride (~94%) and water to minimize carbon steel corrosion due to chlorides? Do you know any Web sites that have guidelines regarding corrosion of carbon steel vs. pH?
Category: Corrosion
What causes corrosion from ethylene glycol?
If a mixture of 50% warm ethylene glycol C2H6O2 and 50% water comes in contact with 6xxx series aluminum, it pits the bare machined surface. What is the reaction product? Will any product of oxidation/reduction get deposited? What is the reaction chain?
Category: Corrosion
Using Aluminum in Water Treatment Plants
Can I use aluminum as construction material for a hydraulic channel flocculator in water treatment plants? Usually the water has about 3.0 to 5.0 of chlorine units and it is slightly corrosive.
Category: Corrosion
What is the difference between 304 and 316 stainless steel?
Generally, SS 304/304L is assumed to be corrosion-resistant material. But when we come to Piping Specs with SS 304/304L MOC, its value is taken as 0.063 inches -- same for SS316/316L . Please explain.
Category: Corrosion
Is galvanization possible only on threaded piping?
Galvanization is done on process piping to protect it from corrosion. Is galvanization possible only on threaded piping? If so, is it true that for some piping components, galvanization is mandatory but for some it is not?
Category: Corrosion
Discussing Carbon Dioxide and Carbon Steel In Petroleum Operations
We will have a fuel gas treatment system that will be operated at about 6 - 10 barg and 60 - 90 C. The gas contains maximum 6% carbon dioxide and no hydrogen sulfide. Should we have to use SS316L or is Carbon Steel with 3 - 6 mm corrosion allowance adequate? The design life is 10 years. This is a schedule-driven project, thus Carbon Steel material will enable us to maintain the project schedule.
Category: Corrosion
Hydrofluoric acid corroding glass site glasses
Small amounts of hydrofluoric acid (HF) in a moist organic process system are corroding the glass site glasses in the process piping, especially at the vapor-liquid interface. Initially the glass etches over so you cannot see through them; finally the glass is completely penetrated.Is there a sight glass material available that will beter tolerate this process stream?
Category: Corrosion
Protective Coating
What is the best protective coating to prevent corrosion on
carbon steel? Also, there is some amount of water that sits on this CS plate which expidites corossion formation?
Category: Corrosion
Corrosive liquid and materials
Are there chemical plants that utilize and circulate solutions of chlorine, and if so, what are the preferred materials used for piping and pumping components? Is stainless steel, bronze or cast iron preferred for these chlorine solution processes?
Category: Corrosion
Corrosion of metals in saltwater
I have buried pipelines that are surrounded with water with a salinity of about 52,000 ppm. For these pipes, I was advised to use Duplex SS, SS 316 L, SS 310 or nickel chrome, but I still cannot obtain any document stating the exact salinity the materials can withstand and under what conditions. Please advise.
Category: Corrosion
Glass tubing
I've never seen glass tubing used in pharm processes. Why? Also, what grade stainless steel do you use, and how do you prefer to clean it, before usage?
Category: Corrosion
Chloride stress corrosion
Can you explain something about "chloride stress corrosion?" I came across it in a maintenance manual.
Category: Corrosion
Corrosion-resistant dust collector materials
What material of construction would best suit a power that is sprayed with 5% hydrochloric acid? My process needs a new dust collector for this application. I've heard alloy 2205 would be a more cost effective choice over Hastalloy, but will it resist corrosion as well?
Category: Corrosion
Material suitable for sodium hypochlorite
Can you suggest a suitable material of construction for sodium hypochlorite manufacturing? The minimum requirement is better heat transfer and less corrosion.
Category: Corrosion
Salinity endurance of stainless steel
I am a biochemical engineer and want to know whether a bioreactor of material construction of SS316L is capable of withstanding a salinity of 18% and PH 8. If not, what material can substitute stainless steel?
Category: Corrosion
Corrosion of silicon bronze
I would like to know whether silicon bronze corrodes or erodes when used in sea water service?
Category: Corrosion
Defining "Green Chemicals"
As the Industrial Water Treatment Program Manager at the federal installation, I am interested in resorting to "green chemicals" in the chemically treating all the boilers, cooling towers and closed loop systems at this installation. Is there a clear definition of what constitutes "green chemicals?" Does that vary from state-to-state, region-to-region, and who has the final word on what is or isn't "green chemicals?"
Category: Corrosion
Metallizing diverse infrastructure applications
I am interested in metallizing the interior of steel potable and non-potable water, as well as fuel and above and underground storage tanks (ASTs/USTs). The alloy of preference for the metallized coating is 85/15 Al/Zn. I would appreciate any information regarding metallized coatings in addressing the above infrastructure applications.
Category: Corrosion
