influence of pressure on NACE compliance

[metboss]

Hi all,

We placed the order to procure down hole equipment (Drilling)and one our requirement is material 13% Cr shall be in compliance with NACE MR-0175.
Now our supplierhas come up with clarification that since burst pressure (design rating) is 8000 psi, NACE MR-0175 compliance cannot be met. I have gone through NACE MR-0175; bit, I was not able to get any info related to burst pressure influence on NACE compliance. Is there any correlation ??

Regards

 

[CoryPad]

Perhaps the burst pressure requires the product to have a strength higher than 22 HRC, which is the maximum allowed by NACE MR0175/ISO 15156.

 

[metboss]

Thnaks corypad,

But our standard restricts hardness values for 13%Cr material to 22 HRC max.

 

[CoryPad]

Yes your standard restricts the hardness to 22 HRC so that the material is in conformance with NACE MR0175/ISO 15156. However, perhaps the wall thickness of this part is too thin and requires a material strength above 22 HRC to prevent bursting. Hence, the supplier stating that the material will not conform to NACE MR0175/ISO 15156.

 

[1gibson]

If you can't develop the required material strength due to the hardness limit, and you can't increase material thickness to handle the stress, then it won't work.

 

[SJones]

What partial pressure of H2S have you informed the supplier to work with? It could be that, if you have only given them an H2S concentration, they are simply deriving an H2S partial pressure using the burst pressure rating and finding that it exceeds the allowable limit. If that is the case, you need to advise them of the (realistic process) design pressure to compute the partial pressure.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

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

 

[jbeckhou]

Can you tell us the part description?

Petrotrim Services, LLC

http://www.petrotrim.com