Both alloys are weldable. If you are asking which alloy requires preheat and post weld heat treatment control during welding, it would be the 13% Cr. The 25% Cr Duplex SS requires control over the interpass temperature during welding.
Selection of filler metal is critical for either alloy in terms of matching suitable strength and the necessary corrosion resistance.
In my experience with autogenous welding the 25% Cr duplex is less difficult to weld.
Metengr hit the big one. If you are using filler then selection of the filler is very critical.
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Corrosion never sleeps, but it can be managed.
Since someone brought it up....
These are strange alloy to compare.
The duplex is higher strength and better corrosion resistance. There is a big gap between these alloys in terms of properties and performance.
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Corrosion never sleeps, but it can be managed.
Some additional information. I believe the 13% Cr alloys referred to in the original post are supermartensitic stainless steel alloys (13%Cr-4%Ni and Mo) with low carbon content (0.01%). Apparently, consideration is being given to using supermartensitic stainless steel for flowlines in sour and sweet crude applications as an alternative to the more expensive duplex SS, and an improvement over carbon steel.
These alloys have similar weldability to the duplex and superduplex stainless steels. PWHT is an option to reduce hardness and increase weld metal toughness. I would suggest further review of the following web site;
metengr,
Thanks for the website. Agree that weldability of the duplex and and supermartensitic stainless will be comparable. Welding costs would favor the supermartensitic s.s (essentailly derivations of CA6NM) depending on toughness requirements.
