duplex welding

Date 08-27-2010 08:07

Hello

I'm looking for reference on the maximum weldable wall thickness of a vessel made in Duplex / Super Duplex Stainless Steel. I mean i'll like to know what is the max recommended and realistic wall thickness that is possibile to achieve in a vessel using a Duplex SS. I've found some reference of wall thick up to approx 50 mm. The design code is AMSE VIII div I or div II.

thanks in advance

Vittorio

By js55

Date 08-27-2010 11:15

The wall thickness limitations would be related more to the ability to achieve phase balance in a really thick base material.
And if you have an application in Div 2 for more than 2" thick I'd say you have a serious service.

By MMyers

Date 08-27-2010 16:32

"The wall thickness limitations would be related more to the ability to achieve phase balance in a really thick base material. "

To add to that... without forming sigma or other undesirable phases. I have no personal experience with welding thick duplex, but discussion I have had with people who have say sigma is a serious concern with thick weldments.

By js55

Date 08-30-2010 12:55

Once you get into the multiple pass regime it really doesn't matter if you have 15 passes or a 115 passes. If you control the heat input and interpass temp you can avoid sigma at least as much as any weldment can with any particular duplex inmind.

By nantong (**)

Date 08-30-2010 12:40

Maximum weldable thickness? Maximum thickness from a welding perspective I cannot see as a problem however manufacturing the material I would think possibly a problem. How do you solution anneal extreme thicknesses of material and maintain a uniform phase balance throughout the the thickness and avoid third phase precipitates?