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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.

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