Determining PWHT cycle for Butt Weld Carbon steel Pipe A 106 Gr.b ,_P No.-1 ,Group No.1

[Ashwani Kumar]

Dear Respected Members and Welding Experts.

i have to prepare the PWHT cycle for butt weld A 106 Gr.b Pipe joints and Tee joints with pipe and #300 wnrf flanges (carbon steel)for below section size :-
a) 2" sch 160 (t=8.74mm)
b) 2" sch xs (t=5.54mm)
c) 2" sch 40s (t=3.91mm)

As per WPS -
Interpass Temp = 150-200 deg C
soaking temperature is 600±10 deg C
soaking time is 2-3 hour
Filler wire is ER70S-2,F No.-6 & A No.-1,

As per ASME SEC VIII
I have selected following Data for PWHT cycle
1. Heating Temperature = 95 deg C
2. Heating Rate = 83 deg C /hr
3.soaking rate= 600 dec & 3 Hour
4. Cooling Rate= Furnace cooling .

Please guide and correct me, if i am wrong ,As i know that there is not the requirement of PWHT for these thickness ,But as per the requirement of project it is required ,but after PWHT the maximum hardness is limited to PWHT.
i am well aware that due to oxidation rarely the hardness some time greater than 200BHN and is there any chances of induced cracking if selected the wrong parameter for PWHT .

Thank you very much in advance for supporting me .

 

[weldstan]

We have performed PWHT on pipe and components like these with 1 hr hold duration and never had hardness > 200 BHN. Your hold time and cycle will not induce cracking.

 

[Ashwani Kumar]

Thank you sir for your response.

If I will go through the following cycle

1. Heating Temperature = 95 deg C
2. Heating Rate = 83 deg C /hr
3.soaking rate= 600 dec & 3 Hour
4. Cooling Rate= Furnace cooling .

please see the attached image of the drafted PWHT cycle , please share your's comment on this and I want to know the possible result ,if I go as below cycle

 

[Ashwani Kumar]

and what should be the ideal heating Temperature, Heating & cooling rate?? and can I go for furnace PWHT or I should have to go for localized heating?? in addition to this,HIC and h2 teast is also to be conducted and after how much gap of time interval i can go for hardness test,RT ,MT and DPT as these test are also to be conducted before and after the PWHT.

 

[weldstan]

You can do it locally or in a furnace. Make sure the spools are properly supported if done in a furnace.

 

[Ashwani Kumar]

thank you, sir
please comment on the above attached PWHT cycle.

 

[mk3223]

You are correct that it may not need to be PWHT per Code, B31.3, for the 2" A106-B pipe of Sch.160/XS/40. But, it may have a process service requirement for the pipe to be PWHT for the project as you mentioned. You may clarify it with the Process or Material Engineers of the Project.

Regarding the PWHT cycle, comparing to the B31.3 Code, the heating rate is lower and the soaking time is longer. As a result, it may take longer time for the PWHT process.

Since it's the project requirement, you may need to confirm it with the Material Engineer for any changes.

 

[Ashwani Kumar]

Thank you sir
Q.1- Can any Metallurgy expert clarify the aspect and impact analysis w.r.t to phase change or microstructure changes as per above selected PWHT cycle.
Q-2 - As per the ASME SEC VIII there is boundation to go as per WPS ,but as per the same standard ,i think the soaking time is not correctly chosen based on the pipe thickness as 2-3 hour is too much for PWHT of above mentioned thickness, can i go as per specified soaking time as per ASME SEC VIII standard ,but that will contradicts my WPS.
is there in standard mentioned that i can go as per ASME SEC VIII standard irrespective of WPS submitted for Third party Inspection??

 

We're doing the daily work assigned to a person evidently wholly unqualified for the task.
Is that what these forums are intended to do?

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

 

[david339933]

Is this an impact tested WPS?....I see interpass temperature listed and a specified PWHT soak time, other than 1hr/inch.

 

[Ashwani Kumar]

Impact Test not done for this WPS.