Vacuum Degassing Process for seamless pipes, forgings and castings

[Stileman]

Dear sirs,

I kindly ask you about the following issue. I premise, I'm in an HIC environment, NACE MR0103 applicable.

My Client requires all piping (seamless pipes, forgings, castings) to be manufactured during steel making with the Vacuum Degassing Process (aimed to lower Hydrogen content to few ppm).
I find such a requirement to be applicable only to:

- plates (ASTM A516);
- welded pipes (ASTM A672);

because they are susceptible to HIC, but not to:

- seamless pipes (ASTM A106);
- flanges (ASTM A105);
- castings (ASTM A216 WCB).

Do you agree with my experience/understanding? Did it ever happen to you to buy, or manufacture, seamless pipes, forgings, castings with a Vacuum Degassing Process?

Thank you very much for your attention. Best regards,

ES

 

[EdStainless]

We have made seamless pipe from VD material, but that is far from the only requirement.
Trace elements and inclusion amount and shape control are also important.

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P.E. Metallurgy, Plymouth Tube

 

[SJones]

The vacuum degassing process is applied during the steelmaking, not the finished item manufacturing process. Seamless pipe, flanges and castings can all suffer from HIC if the manufacturing activities leave them in a susceptible state. If they were immune to HIC why would their testing be incorporated into NACE TM0284? If the client requires it, why not just give it to them?

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.

 

[Stileman]

@EdStainless
Yes, of course Vacuum Degassing isn't the only parameter to control. Anyway interesting to know that you manufactured pipes with such a method.

@SJones
From this point of view, Client specification is little bit contradictory. From one side, it asks for Vacuum Degassing process, on the other side (the following paragraphs) it states that there's no need to perform any NACE TM0284 tests on seamless pipes, forgings, fittings and casting because they're not susceptible to HIC. Don't you think this to be slightly contradictory?
Often Client specifications aren't exempt from errors or excessively demanding requirements for relevant projects (it happens they blindly do "copy and paste" same requirements from one project to another without careful evaluation). So, I consider my duty as Piping Material Specialist, to be able to assess and evaluate Client requirements. Otherwise, it would be too simple as a job, don't you think?
Just to be precise, NACE TM0284 doesn't address anything to castings but it does to seamless pipes, forgings and fittings (apart from plates, of course).

I asked a meeting with Client to discuss the matter. I'll keep you posted for final decision.
Thanks for your contributions. Best regards,

ES

 

[EdStainless]

There are many steel mills that make plate and bar product that is V-D as a matter of course, it is the only way that some mills can make steel.
Many people feel that this is better quality steel. In reality other steel can be as good, but V-D does help.
Are they saying that in this project there is no risk of HIC? That could be true.
Just get it from them in writing.

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P.E. Metallurgy, Plymouth Tube

 

[SJones]

@Stileman - maybe the client believes that vacuum degassing the steel is a sufficient palliative to warrant omission of subsequent HIC testing. Yes, you can be precise in that TM0284 doesn't specifically address castings, but it doesn't preclude castings either. You appeared to be labouring under the misapprehension created by clause 8 of ISO 15156-2 with respect to the occurrence of HIC.

Assessing and evaluating client requirements is generally achieved in a dialogue with the client rather than crowdsourcing answers on an internet forum. Good luck with your meeting, and we look forward to learning of the outcome.

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.