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Re: [MW:13533] RE: 13526] Preheat & Interpass temperature - Reg

By Materials & Welding
Preheat is a function of many parameters like
a. Carbon Equivalent (for Carbon steels)
b. Material Type
c. Thickness (Restraint)
d. Hydrogen level
 
For materials covered under ASME Sec.II, below mail from Mr.John Henning will provide a guidance based on construction codes
 
For structural material , Appendix in AWS D1.1 will provide guidance.
 
Interpass temperature is also an important parameter for which maximum values are specified in the WPS. Generally
 
For Carbon & Chrome-moly steels - 300 to 350 degC max
For Stainless Steel  - 175 degC max
For Nickel ALloys - 150degC max
For superaustenitic steels - 98degC max
 
Increasing the Interpass temperatures above the prescribed values will result in Grain coarsening, sensitisation, hot cracking, precipitate formation etc.. depending upon material type.
 
Thanks & Regards
 
J.Gerald Jayakumar
0091-9344954677
From: John Henning <jhenning@deltak.com>
To: materials-welding@googlegroups.com
Sent: Friday, January 20, 2012 9:12 PM
Subject: [MW:13527] RE: 13526] Preheat & Interpass temperature - Reg

Typically preheat recommendations will come from the construction Code
(for example Section I - PW38,  Section VIII - Appendix R, or UCS-56
notes).  High restraint, or other factors, may result in using a higher
preheat than recommended/specified in the code.  General rule of thumb
for interpass; 600F max. for carbon and  alloy steels  {Q&T or specialty
steels - consult material supplier}, 350F max for stainless, and 300F
max for duplex stainless and nickel based.

John A. Henning
Welding & Materials

-----Original Message-----
From: materials-welding@googlegroups.com
[mailto:materials-welding@googlegroups.com] On Behalf Of Ramesh
Deenathayalan
Sent: Friday, January 20, 2012 1:40 AM
To: materials-welding@googlegroups.com
Subject: [MW:13526] Preheat & Interpass temperature - Reg

Dear friends,

While writing the WPS based on ASME SEC IX, how can we determine the
minimum preheat temperature and maximum interpass temperature??  Kindly
advice.

Ramesh D

Sent from my Nokia phone

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