Joint Thermocouple to Vessel (UW-37(h)) 1

[WE17]

Dear Expert,s
Good morning,
I have some case(bulding Pressure Vessel based on ASME IIIV Div 1 )below client give an question Please kindly help to solve :
Client said: You need Procedure to Joint Thermocouple to Pressure Vessel He show me UW-37(h) Capacitor Discharge Welding...
(Our Procedure PWHT attachment mention Capacitance Discharge Welding)
Before I never used WPS for weld Thermocouple to vessel
In my understanding UCS-56 ASME 8 div 1 not mention about it, But ASME 8 div 2 6.6.5.6 of course required WPS,
my question are :
1. according to the UW-37(h) Do i need to make WPS? or only make procedure to Join it?if Yes How to make the procedure?
2. am I correct to interpretation UCS-56 div 1 and 6.6.5.6 asme 8 div 2 about WPS for weld Thermocouple to Vessel?
3. It is Brazing or Welding?
Thankyou for answer my question

 

[GenB]

I do not in it all. Capacitor discharge is same or similar to stud welding. Since this is temporary you may not even need proof tests. QC inspection after removal of t.c. since the base metal can or may be damaged.

 

[metengr]

Here is what UW-37 (h) states;
(h) Capacitor discharge welding may be used for welding
temporary attachments and permanent nonstructural
attachments without postweld heat treatment, provided the
following requirements are met:
(1) A welding procedure specification shall be prepared
in accordance with Section IX, insofar as possible
describing the capacitor discharge equipment, the combination
of materials to be joined, and the technique of application.
Qualification of the welding procedure is not required.
(2) The energy output shall be limited to 125 W-sec.

So, yes, you need a WPS. It does not need to be qualified for Section VIII, Div 1 application, it is simply an instruction document for the welding operator to ensure consistent welding using capacitor discharge welding. The key is to limit the energy input to 125 W-sec to avoid introducing a larger base metal heat affected zone. It is welding.

 

[WE17]

Dear Metengr And GenB,
Thankyou for advise it very helpfull. I am new working on pressure vessel company so I have lot of question. Thankyou

 

[Fizza453]

Dear Metengr,

What about the performance qualification for these welds?
In my opinion, performance qualification is also not required as per UW-29(b)(2), please advise.



Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[metengr]

You are correct.