Requirement of No. of Thermocouples.

[Ramchandra vichare]

Dear Experts,

With reference to the above mentioned subject , during Heat-treatment of Piping spool joints I insisit one of my vendor to used thermocouples as noted below:-
Up to 4"NB = 1 no.(Bottom side)
Above 4" to 8"NB= 2 nos.(top & Bottom)(say 180Deg.)
8" to 24"= 3 nos (120Deg)
Above 24" =4 nos.
and according to accepted Heattreatment Procedure it was alo acceptable but unfortunitaly delay in Heat treat the joint; vendor is not ready to follow Procedure due to the reseason referred above & no where written in ASME 31.3 regarding the requirement of Tharmocouples. Reauested experts to Guide guaide me why we are placing thromocouples? I think it is control soaking anyhow;let me tell were I will get ready reference and documentryevidence for requiremnt of Number of thermocouples? Is any effect during soaking time or any metallourgicval changes will be there if we use one thermocouple instead of above? . Pl be guaide in detail with documentry evidence.

Regards,

RK Vichare
Mumbai-India

[Shashank Vagal]

Dear members, In all these arguments one imp aspect remains ignored, the very purpose of a thermocpuple, TC. All the requirements given in B31.3, Shell DEP, Aramco SP etc are the minimum requirements. What we have to ensure is that all the area required to be heat treated is indeed heated and soaked as specified.  It then becomes obvious that to meet this requirement you may need some additional TCs at certain locations whereby all required area gets speicified heat treatment. Sometimes I have used 6 to 8 TCs to satisfy myself on adequacy of HT because of the job geometry. Regards, Shashank Vagal --- On Fri, 23/9/11, Ramchandra vichare <vicha...@indiatimes.com> wrote:

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[jesti fer]

Mr.Vichare, The no. of thermocouple for PWHT, it is no written any where in the code but ones the procedure is approved, it should be follwed. if you whant change the no of thermocouple you can reverse the procedure. But normaly what is the client requirment that should be follwed, like thermocuople type and distence between thermocouple, heating & cooling rate, Unrestricted heating & cooling rate and etc.... I have seen that diffrent procedure one is requried up to 2" 1thermocouple, 2" to 4" two and 6" to 18" three and more ...... other one procedure up to 8" one, 8" to 24" two and etc....   Regards Jesti

--- On Fri, 9/23/11, Ramchandra vichare <vicha...@indiatimes.com> wrote:

From: Ramchandra vichare <vicha...@indiatimes.com> Subject: [MW:12507] Requirement of No. of Thermocouples. To: material...@googlegroups.com

[pgoswami]

Mr. Vichare,

 

ASME B-31.3 does not have any specific instruction on placement of thermocouples for local PWHT of pipe spools. AWS D-10.10-1999-Recommended Practices for Local Heating of Welds in Piping and Tubing is the industry standard followed to develop local PWHT standards and guidelines.

 

Please see the recommendation of AWS D-10.10 on the recommended no of thermocouples to be placed for PWHT of such pipe spools. Further detailed instrctions are available in this standard.

 

PWHT is extremely important for B-31.3 piping as the service environment is extremely conducive to SCC, and all forms of hydrogen assisted cracking. Moreover since spools are locally PWHT-ed there are every possibilities of  mistakes.Common mistakes could be  wrong ramp rate, incorrect temperature of PWHT, improper width of the weld+BM heated to the PWHT temperature, sudden power loss during PWHT, wrong thermocouple placement, improper calibration of strip chart (recorder), damaged thermocouple ends so on & on.

 

You may please insist the PWHT contractor  to meet  all requirements of D-10.10.

 

 

Pradip Goswami,P.Eng.IWE

Welding & Metallurgical Specialist & Consultant

Ontario,Canada.

Email-pgoswami@sympatico.ca,

pgos...@quickclic.net

 

---

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Shashank Vagal
Sent: Friday, September 23, 2011 4:36 AM
To: material...@googlegroups.com
Subject: Re: [MW:12508] Requirement of No. of Thermocouples.

To unsubscribe from this group, send email to materials-weld...@googlegroups.com

[Darapu Dattatreya]

Dear Experts,

 

Can you guide me some body for this, we are using the LPG gas as a fuel for Heat Treatment & Solution Annealing of our SS Components, but one of our Inspection agency not allowing and accepting the heat treatment process with LPG Gas fuel due to accomulation of corborization on the SS components at the time of heat treatment.

 

Is it acceptable the heat treatment process with LPG Gas as a fuel for SS Components.

 

Pl. help me out in this matter and Iam stucked very badly.

 

 

Regards,

 

D.Dattatreya

G.M.Technical   

 

   

[prem nautiyal]

Hi   What is the service requirement and construction code of your equipment ?   Mostly for Austenitic SS components electrically heated furnaces are preferred for heat treatment to avoid pickup of impurities from oil/gas fired ones. For nuclear equipments electrically heated furnace  is mandatory.     Regards   Prem Nautiyal Cell: 9769316004 --- On Mon, 10/15/12, Darapu Dattatreya <darapu_d...@yahoo.com> wrote:

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[Darapu Dattatreya]

Hi Prem,

 

Thank you very much your prompt response, we are one of the leading pipe fittings manufacturer's in india and we are following ASME B 16.9 Code for constructionof pipe fittings.

 

Regards,

 

D.Dattatreya 

G.M.Technical

From: prem nautiyal <prem_na...@yahoo.com>
To: material...@googlegroups.com
Sent: Monday, October 15, 2012 11:30 PM
Subject: Re: [MW:15654] The LPG Gas fuel in Acceptable for Heattreatment of Stainless Steel components

Hi   What is the service requirement and construction code of your equipment ?   Mostly for Austenitic SS components electrically heated furnaces are preferred for heat treatment to avoid pickup of impurities from oil/gas fired ones. For nuclear equipments electrically heated furnace  is mandatory.     Regards   Prem Nautiyal Cell: 9769316004 --- On Mon, 10/15/12, Darapu Dattatreya <darapu_d...@yahoo.com> wrote:

From: Darapu Dattatreya <darapu_d...@yahoo.com> Subject: [MW:15635] The LPG Gas fuel in Acceptable for Heattreatment of Stainless Steel components To: "material...@googlegroups.com" <material...@googlegroups.com> Date: Monday, October 15, 2012, 12:39 PM

Dear Experts,   Can you guide me some body for this, we are using the LPG gas as a fuel for Heat Treatment & Solution Annealing of our SS Components, but one of our Inspection agency not allowing and accepting the heat treatment process with LPG Gas fuel due to accomulation of corborization on the SS components at the time of heat treatment.   Is it acceptable the heat treatment process with LPG Gas as a fuel for SS Components.   Pl. help me out in this matter and Iam stucked very badly.     Regards,   D.Dattatreya G.M.Technical

-- To post to this group, send email to material...@googlegroups.comTo unsubscribe from this group, send email to materials-weld...@googlegroups.comFor more options, visit this group's bolg at http://materials-welding.blogspot.com/http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.