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pipe material for aqueous solution

pipe material for aqueous solution

pipe material for aqueous solution

Hi there

hope everybody is safe in this period

Please, I'd need a piece of advice from you.

I need to select a suitable pipe material for a aqueous solution containing
o chloride 1100 mg / L
o sulfate 1200 mg / L

This pipe will be utilized in an heat exchanger.
The circuit would be closed.

I have no other pieces of information.

I do think that copper C12200 is not suitable because of both elements,nor CuNi C70600

I am thinking about a solution with Stainless Steel.

Please, could anybody give me an hint concerning this topic, and maybe suggest me a suitable literature ?

Thanks in advance

RE: pipe material for aqueous solution

You don't mention maximum temperature, which is very relevant to alloy selection.
Is the service clean; i.e., non-fouling over time?
Corrosion data for mixtures like yours can be hard to come by. Further, contamination can have a multiplying effect on rates.
You are into some fairly expensive options so it is worth doing some testing in the actual fluids and service conditions. That, and/or find out what others in the same industry who do the same thing are using.
The Nickel Development Institute might be able to help.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: pipe material for aqueous solution

maybe a duplex will suits your request but as
ironic metallurgist posted more information is needed.



RE: pipe material for aqueous solution

Normally, copper alloys such as 90/10 are forbidden for use in the presence of sulfides. I don't know that sulfates are particularly corrosive to copper but sulfate reducing bacteria are. Microbial growth may or may not be easy to prevent. I don't know about the corrosive nature of sulfates.

RE: pipe material for aqueous solution

yes maybe Hastelloy C would result.

"Hastelloy C-22 alloy composition has many benefits that help enhance resistance to pitting, crevice corrosion, and stress corrosion cracking. It has excellent resistance to oxidizing aqueous media including wet chlorine and mixtures containing nitric acid or oxidizing acids with chlorine ions."


RE: pipe material for aqueous solution

Temperature first. There is a wide range of materials that could be used.
But like you said the S pretty much rules out Cu and CuNi alloys. The Cl level rules out basic (304/316) SS grades.

You say sulfate, are they really sulfates, or are there other forms (sulfides) present as well?
Are there any other trace contaminates?
What material is the rest of the circuit made of?
What size of line is this (diameter and length)?

Is this for the tubes in the heat exchanger? Who is designing it? If so I presume that they will be small (1/2"-1" diameter) and thin wall (0.028"-0.065") depending on temperature, flow, and pressure.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

RE: pipe material for aqueous solution

I concur with some of the previous opinions that you are probably into the category of elite C alloys, especially if there is any significant elevated temperature:
Inconel 686, VDM Alloy 59, Hastelloy C-22, C-2000, C-276
Seamless of course.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: pipe material for aqueous solution

Either be lazy and buy seamless, or write a spec that requires inspection and by the properly made welded tubing and save a lot of money. And then still run the risk of getting incorrectly heat treated seamless product and having failures.

Unless this system is hot it doesn't need a Ni alloy, there are plenty of high performance SS grades that are used on seawater heat exchanger service all of the time, superaustenitic (AL-6XN, 25-6Mo), superferritic (SEC-CURE), and superduplex (Zeron100, 2507) might all be candidates.
At high temps you are moving into Ni alloy range.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

RE: pipe material for aqueous solution

EdStainless gives good advice ...

But since the original poster has now abandoned this thread, we will never know the system temperature.

IMHO, always compare the cost of your candidate materials (superaustenitic, superferritic , and superduplex ) to C-276 NI alloy

C-276 came off patent a couple of years and the Chinese supplied tube is being priced very competitively

Sr. Process Engineer

RE: pipe material for aqueous solution

The other option is Tigr2, it is about the same price as SEA-CURE, the 2507 and AL-6XN are about double that price, and the Ni alloys would be about triple that amount.
The issue with Ti is the mechanical weakness, it requires designers that know what they are doing or you end up with a long term headache.
Yes I made a pretty good living off of replacing bad seamless tube with good welded tube. Bad HT is amazingly common, so are people trying to anneal dirty tubes.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: pipe material for aqueous solution


We are in a period where technical quality of alloys is noticeably declining, and it is causing problems for users who place extra demands on items such as fittings, valves, welding wire, etc. This is not just due to Far East sourcing, but the fact of the poor control of scrap going into electric remelting furnaces.

As you say, heat treatment can be a problem. Far East suppliers seem to think that the list of ingredients is equivalent to the soup, but you also need to know how to cook the soup.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: pipe material for aqueous solution



RE: pipe material for aqueous solution

You made no mention of pressure or temperature. Without that information, plastic is the obvious solution.

RE: pipe material for aqueous solution

Tug, he said, "This pipe will be utilized in an heat exchanger." Would you still recommend plastic?

RE: pipe material for aqueous solution

Sorry, I missed that line. They'll just need to make the exchanger much larger.

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