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Re: [MW:32480] interpass temperature

By Materials & Welding
Dear Rameez khan RK,

Interpass temperature is generally mentioned as MAXIMUM. 

Hence Approved PQR interpass temp. is 290 but in WPS its mention 340 c is acceptable. 

Please note that code has specifically mentioned as important criteria when impact test is essential in application.

It is  a delicate balance between time & temperature for preheat, post heat cooling rate, Thickness, Heat Input, Ambient Conditions & Heat Transfer. 

The WPS & PQR is the basis of the starting point for establishing design requirements. At times simulations tests are carried out to ensure & impose limit on preheat, interpass temperature control & PWHT requirement to regain requisite material properties in as delivered conditions of final equipment / structures. Hence it is a designer driven MOC & welding technology fulfillment to achieve desired end results. 

The application can vary from structure, Pressure vessels, aero, nuclear, defense & rocket to several others using welding as technology. 

The result of interpass is measured by Final Hardness in parent material, HAZ & weld metal as per specified by designer. 

Attached please find extract of general theory regarding understanding of interpass temperature requirement. 


Best Regards,
C.B.KAPADIA



On Monday, 23 August, 2021, 08:40:38 am IST, Rameez khan RK <rk.rameezkhan21@gmail.com> wrote:


Hello Experts,

Can any one tell me about interpass temperature for carbon steel pipe as [per code and standards.

WE facing one issue here our Approved PQR interpass temp. is 290 but in WPS its mention 340 c so please defined and what is actually interpass temp as per codes per standards.


thank you   

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