Carbon Steel Corrosion/damage

• Oct 10, 2019

• #2

cap1a79

Materials

Jul 11, 2013

109

US

If you share some detail information as below, you will get some advice to establish guideline to find out the root of the cause.

i) Temperature - 300 C
ii) Service unit / Detail location
iii) Type of the facility (ex., heat exchanger, pressure vessel)
iv) Any corrosive component (ex., H2S, CO2)
v) Service fluid
vi) Any other information?

Lee SiHyoung,

 

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• Oct 10, 2019

• #3

SJones

Petroleum

Apr 22, 2001

3,946

GB

300 deg C - insulation? Corrosion under insulation (CUI)

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

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• Oct 10, 2019

• Thread starter
• #4

aasd25

Industrial

Oct 9, 2019

6

MY

Hi cap1a79,

i) Temperature - ~300 C
ii) Service unit / Detail location: hydrocracker unit
iii) Type of the facility: heat exchanger
iv) Any corrosive component: shouldn't be but Cl and S was detected on the CS piece

 

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• Oct 10, 2019

• Thread starter
• #5

aasd25

Industrial

Oct 9, 2019

6

MY

Hi SJones,

I don't think it is CUI because it is not on the surface in contact with the insulation material. It is the inner side.
It is strange to see carbon steel material turned into layers like this, never seen that before.

 

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• Oct 10, 2019

• #6

SJones

Petroleum

Apr 22, 2001

3,946

GB

Glad we established that it's on the inside.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

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• Oct 10, 2019

• #7

cap1a79

Materials

Jul 11, 2013

109

US

Considering the service unit, temperature and the selected material, the failure is very similar to H2 / H2S corrosion or Sulfidation.
Check whether the original material selection and the corrosion allowance were proper or not based on Couper-Gorman curve (for H2 / H2S Corrosion) & McConomy curve (Sulfidation) and if yes, check if process conditions were properly operated with the given CS selection and the corrosion allowance.

Lee SiHyoung,

 

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• Oct 18, 2019

• #8

Corroneer

Mechanical

Jan 13, 2006

63

SA

Looks like high temperature damage. Are you sure the temperature did not increase significantly from 300 oC.

 

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• Oct 21, 2019

• Thread starter
• #9

aasd25

Industrial

Oct 9, 2019

6

MY

Thanks Lee!
I will check on it.

 

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• Oct 21, 2019

• Thread starter
• #10

aasd25

Industrial

Oct 9, 2019

6

MY

Hi Corroneer,

In fact the highest temperature observed before the failure was 373°C. This is the fluid temperature, not the CS surface temperature, I guess it could be close to 373°C but still within the design temperature.
If it is high temperature damage, does it mean that the material is not suitable?
The design temperature is 400°C though.

 

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• Oct 22, 2019

• #11

cap1a79

Materials

Jul 11, 2013

109

US

It depends on H2S %, elemental sulfur wt% and corrosion allowance mm. Share the above information.










Lee SiHyoung,

 

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• Oct 22, 2019

• #12

mrfailure

Materials

Aug 7, 2011

816

US

I think it is difficult to understand what really happened without at least making a metallographic cross-section through-wall through the damage. Both metallography and microhardness should help in this instance.

 

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• Oct 22, 2019

• Thread starter
• #13

aasd25

Industrial

Oct 9, 2019

6

MY

Hi mrfailure,

Yes we are going to do that soon. I just would like to have some insights if anyone here have seen a similar damage before.

 

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