HOT EXPANSION -SEAMLESS PIPE-API 5L-HIC/SSC

[peter vaf]

Dear expert,

Is there any evidence to suggest that the application of Hot Expansion seamless pipe(API 5L) is not suitable for HIC/SSC material specifications?

However, I found some technical notes in this regard below :

Disadvantages of thermal expansion seamless steel pipe:

1. After thermal expansion, the non-metallic inclusions (mainly composed of sulfides and oxides and silicates) in the thermally expanded seamless steel pipe are pressed into thin sheets, resulting in delamination (interlayer). Delamination can seriously damage the tensile properties of heat-expandable steel pipes in the thickness direction, and interlaminar tearing is likely to occur when the weld shrinks. The local strain caused by welding shrinkage is often several times the yield point strain, which is much larger than the local strain caused by the load.

2. Residual stress caused by uneven cooling. Residual stress refers to the internal self-equilibrium stress without external force. Such residual stresses exist in heat-expandable steel pipes of various cross-sections. Generally, the larger the section size of the section steel, the greater the residual stress. Residual stress is of course self-phase equilibrium, but it still has a certain influence on the performance of steel components under the action of external force. Such as deformation, non-chaos, anti-fatigue and other aspects may have adverse effects.

 

[1503-44]

If used appropriately and with inspection and continued testing as appropriate for service conditions, generally its fine, but ... you do not state those conditions.

Any pipe material might not meet requirements either when fabricated or after having been in service for some amount of time. HIC usually only becomes a problem after many years of service, but can be experienced quickly, if poorly fabricated, or fluids carried are high in adverse composition or if temperatures and pressures are at elevated conditions. That's why inspection upon fabrication and a continuous inspection and testing program developed for specific applications may be necessary to ensure long time service adequacy.

Depending on specific service conditions, other materials might have a better long term response and a metallurgist would be best able to advise on the appropriate materials to use.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

I had to go look this up as I had never heard of it before, but appears to be mainly used by some Chinese mills to make larger diameter thinner SMLS pipe starting with a smaller seamless pipe, heating it and then expanding it at high temperatures in a mill.

Details of this process seem to be difficult to come by and its not clear under what specification, if any, this now bigger, but thinner pipe is made or what the ratio is between starting pipe and finished pipe.

Heating and then cooling any pipe material like this could have issues with the properties or resistance to attack by H2S or similar.

This needs a metallurgist to do some tests on it.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[EdStainless]

Just remember that the only thing that the finished pipe has in common with the original is chemistry.
You have to re-heat treat, re-do all NDT, re-do all destructive and mechanical testing, as well as the HIC testing on the final product.
HIC resistant material should be very clean to start with and have little issue with inclusions.
If this was my project I would either be at the mill to witness all testing or would order the material with the requirement that all lab testing be done at a third party of my selection, and I would still visit the mill to witness selection of samples.

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

 

[SJones]

Not a generally applied linepipe manufacturing process for oil & gas. Looks to be for large diameter, thick walled seamless pipe - high pressure steel catenary risers perhaps? Properly controlled post forming heat treatment should sort out the microstructure, and residual stress issues, for the pipe to get through the generally applied manufacturing procedure qualification and production quality control H2S corrosion testing.

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.

 

[peter vaf]

Dear All,

I appreciate the responses and insights from everyone.

The primary concern at hand revolves around the absence of guidance in API 5L Standard ,regarding the approved process for sour service in the HOT EXPANSION production method.

While companies like TOTAL have insisted on customer confirmation, the pivotal questions are:

1-Does API conduct certification for the HOT EXPANSION product line for ANNEX H?
2-Is the production method employed for a 30-kilometer pipeline scientifically and technically sound?
3-In the absence of the above, it appears that API 5L has not imposed any restrictions.
It appears that while this method may be suitable for specific pipe applications(BATCH Production method) with small QTY, its scalability to high volumes raises concerns (Continues hot rolling method)that may necessitate additional restrictions.

Thank you for your attention and collaboration.

Regards
Peter

 

[SJones]

1. No - the API composite listing will be against API Spec 5L only; it will not single out Annex H
2. Yes. Economically sound? Probably not.
3. Correct - there are no specific requirements for the equipment to be used for manufacturing seamless pipe

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.

 

[peter vaf]

Dear SJones

Thank you for your reply


1. No - the API composite listing will be against API Spec 5L only; it will not single out Annex H(J)====>It appears that the API Auditor will be releasing the API MONOGRAM based on the mill capabilities outlined in the API 5L Specification. Please refer to the CERTIFICATE

for two different mills with varying scopes of acceptable products for API.

 

[SJones]

@peter vaf

Thanks for pointing that out. I hadn't noticed the expandable certificate menu on the Composite List, and the application form for licensing

https://www.api.org/-/media/Files/C...PI_5L_Licensing_Information_Form_20230821.pdf

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.