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[MW:2400] FW: 2396] QW-407 Postweld Heat Treatment

By Materials & Welding

Dear Mr Tong

Opinion given in red letter

 

Regards

 

Hegde P.B.

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of tong tong
Sent: Thursday, June 11, 2009 6:57 AM
To: materials-welding@googlegroups.com
Subject: [MW:2396] QW-407 Postweld Heat Treatment

 

QW-407 Postweld Heat Treatment

QW-407.1 A separate procedure qualification is
required for each of the following conditions:
(a) For P-No. 1, P-No. 3, P-No. 4, P-No. 5, P-No. 6,
P-No. 9, P-No. 10, and P-No. 11 materials, the following
postweld heat treatment conditions apply:
(1) no PWHT
(2) PWHT below the lower transformation temperature
(3) PWHT above the upper transformation temperature
(e.g., normalizing)
(4) PWHT above the upper transformation temperature
followed by heat treatment below the lower transformation
temperature (e.g., normalizing or quenching
followed by tempering)
(5) PWHT between the upper and lower transformation
temperatures
(b) For all other materials, the following postweld heat
treatment conditions apply:
(1) no PWHT

(2) PWHT within a specified temperature range

QW-407.4 For ferrous base metals other than P-No. 7,
P-No. 8, and P-No. 45, when a procedure qualification test
coupon receives a postweld heat treatment exceeding the
upper transformation temperature, the maximum qualified
base metal thickness, T, shall not exceed 1.1 times the
thickness of the test coupon.

Dear Members,

Above mentioned subject and clauses are referred..I have a few question to ask..

1.  What "PWHT below the lower transformation temperature" means and from where we can get the value of temperature?(PWHT below AC1 is stress relieving i.e. below 723C You get reference temp. in UCS56 of ASME sec VIII Div 1

2.  What "PWHT above the upper transformation temperature" means and from where we can get the value of temperature?Above AC3 generaly above 900C refer Iron Carbon Diagram It depend upon the Metallurgy of CS/LAS / Generally for CS and LAS used in Pressure vessel Fabrication  AC3 temp is between 900-950C and for Sloution annealing of SS 300 series it is 1020-1040 C

3.  What "PWHT within a specified temperature range" means and it is from code and standard such as B31.3, ASMEVIII or etc? It is the temperature range at which the PQR is qualified for PWHT say SR at 600-620C for CS , 680-700 for LAS P4 material

I really need your expertise opinion. Thank in advance

Regards

Tong

 



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