welding of Duplex stainless steel
welding of Duplex stainless steel
(OP)
I have to weld a Duplex stainless steel of P no. 10H .The desing code is ASME B31.3.Code says "PWHT neither required nor prohibited".
How to interprete this statement?
I heard that control of heat input is very essential in welding of Duplex steel.Shall i need to do a PWHT? if yes what PWHT cycle i need to follow? which consumalbes are suitable to weld these by GTAW & SMAW process.
The application is SOUR & Impact test is required in PQR
Thanks in advance.
How to interprete this statement?
I heard that control of heat input is very essential in welding of Duplex steel.Shall i need to do a PWHT? if yes what PWHT cycle i need to follow? which consumalbes are suitable to weld these by GTAW & SMAW process.
The application is SOUR & Impact test is required in PQR
Thanks in advance.





RE: welding of Duplex stainless steel
"PWHT neither required nor prohibited". This is code language for PWHT is not recommended. If PWHT is decided on duplex ss joints, reheat treatment would only be permitted.
RE: welding of Duplex stainless steel
RE: welding of Duplex stainless steel
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: welding of Duplex stainless steel
So you recommend that i should not go for any PWHT,simply weld it & test it?
What about the suitable cosumables?
RE: welding of Duplex stainless steel
lahane, maybe this document can be of some help for you.
htt
RE: welding of Duplex stainless steel
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: welding of Duplex stainless steel
The new and improved version
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Plymouth Tube
RE: welding of Duplex stainless steel
The only option is solution heat reating (expensive). If you have welds they should have been made with what I call a 'non-matching matching' filler metal. The short version of that means that if you re-heat treat, the weld and the base metal will have significantly differing ferrite contents, one of which may be out of spec.
Welding duplex SS is one of the reasons I got out of the manufacturing end of welding engineering ...
RE: welding of Duplex stainless steel
The challenge you face is to develop a good welding procedure, but, there's plenty of help avaialble through the technical departments of reputable consumable manufacturers.
RE: welding of Duplex stainless steel
Duplex stainless steel welding: best practices htt
"Post-Weld Heat Treatment (PWHT) and Cleaning PWHT of DSS is generally not required but may be necessary when detrimental amounts of intermetallic phases have formed. Typically, a full solution anneal followed by a water quench should be considered"
S
Corrosion & Rust Prevention Control
RE: welding of Duplex stainless steel
If the piping requires the PWHT for base metal per codes or end-user's specification, the best solution may be to avoid the DSS.
For instance, when CS with DSS clad is required PWHT per code, you may have to use solid DSS without PWHT or CS with other clad material followed by PWHT.
Thomas Eun