Manufacturing of Welded Fitting A860 X65 With TMCP Plate

[peter vaf]

We have ordered a BW A860 X65 package ,and asked to factory about starting plate .
They confirmed that ,using TMCP as Starting plate with additional Q&T or Normalized heat treatment for reaching A860 toughness @ -46.

It is generally accepted that these steels are not designed for subsequent PWHT and may suffer some degradation in their mechanical properties when re-heated above critical temperatures.

A number of standards, specifications and technical publications acknowledge the influence of PWHT on mechanical properties of the TMCP plate, but provide limited guidance (depend on supplier quality) on how it will affect the properties.

Would you Please help me about such a Manufacturing process Issues and possibility .

 

[EdStainless]

But you will not be doing PWHT on the TMCP material, you will be doing it on Q&T material.
A Q&T or normalize will effectively erase the TMCP thermomechanical history.
So now you are left with chemistry questions.
A different animal.
It may still present issues

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

 

The same microalloy elements that help HSLA steels achieve their phenomenal properties are bad actors in the HAZ during PWHT.
Google 'stress relief cracking'.

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

 

[BenMacier]

As the standard highlights, it's highly chemistry dependent. Could you please post the ladle analyse of the plate?

* Finding a solution is great * Knowing how to implement it is fantastic * Believing it is the only one and best is naive ?

 

[peter vaf]

Dear EdStainless

Thank you so much for your reply.
The pipeline has been designed according to B31.8 ,Which PWHT has been advised for the thickness above 32 mm.

Now, BW Fitting connection at side,(Which have 32.5mm thickness/WPHY65) should be PWHT after welding.

Fitting factory INSIST to use TMCP plate as the starting material along with Q&T to reach a fine grain size for toughness propose(@-46)According to A860 STD.

confusions:
1)PWHT Requirement for weld joint of fitting(fitting manufacturing).
2)Heat treatment to reach toughness requirement According to A860(-46)for TMCP Plates.
3)PWHT of Weld joint of the fitting @site.
4)Alternative using of TMCP Normalized Forming Starting plate as per API 5L Delivery condition (However am not sure about availability/applicability of TMCP Normalized forming for Fitting manufacturing)

 

[SJones]

So what if they start with TMCP if they then run it up to 900 deg C and quench it? Good luck to them as TMCP is pretty lean for responding to a quench. If they are successful, as demonstrated by a manufacturing procedure qualification (you did specify one didn't you), then all you have to worry about is keeping your PWHT temperature at a suitable temperature margin below the tempering temperature.

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 Steve Jones,


Thank you for your reply.
It seems that,for the TMCP plate ,they can just run Heat Treatment between Ar3~Ar1!
Your advice will be highly appreciated in this regard.

 

[SJones]

@peter vaf - given your stated text, you appear to be totally missing the point. The starting plate will be TMCP. The fitting manufacturer will then process the plate into a fitting. In so doing, they will RE HEAT TREAT the material under a quench and temper cycle. The TMCP microstructure will be totally changed, and the material will now be quenched and tempered, and no longer TMCP. Get TMCP out of your head.

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 Steve Jones,

Thank you so much for your Technical Comments.

But ,If the factory using Q&T Plate as starting material at beginning ,They could save the cost of Re-Heat Treatment and process controlling,unless Q&T Plate could not be found at market with the specific Yield Required!

Thank you again for your supporting.

 

[weldstan]

The fitting manufacturer will still have to mechanically test the Q&T plates to verify minimum tensile and impact properties. One would assume that the fitting manufacturer would purchase Q&T plates if they could find them in the required time frame.

 

[SJones]

@peter vaf. It's down to the fitting manufacturer to work with what they can get so long as the end product meets the technical requirements. Take a look at A860 and read the heat treatment section. You will note that it doesn't matter what the starting material condition is. Just go with it and stop panicking.

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.