Hi Maria!
The Schaeffler diagram was published 1949.
Schaeffler, A.L. 1949. Constitution diagram for stainless steel
weld metal. Metal Progress 56(11):680-680B
I'm sure that You can find the diagram in newer publications.
I just want to point out the fact that it's over 50 years old.
If anyone has any comments on the newer WRC-1988 and WRC 1992
diagrams please post them.
Regards
Happy
Maria,
A little background on the various diagrams.
The Schaeffler Diagram was useful for predicting the ferrite content in austenitic stainless steel deposits and dissimilar combinations of carbon steels and austenitic stainless steels.
However, the diagram does not take into account Nitrogen. This brought about the Delong Diagram sometime in the 1970's which incorporated N in the Ni-equivalent formula. But, the diagram was found to misrepresent Mn, and Ferrite Numbers (FN) of highly alloyed compositions. This gave way to the WRC-1988 diagram which corrected the overestimation of FN. The 1992 WRC diagram added Cu factor in the Ni-equivalent formula.
I don't know if I would use the Schaeffler Diagram for DSS to CS. I would use the WRC-1992 which will get you a good estimate. Once you choose a filler metal I would check the weld deposit using a MagneGauge to determine the FN.
You can use a 2209 filler metal or 625 filler metal to join CS to DSS. But this is highly dependent on the service requirements. For temperatures over -50 C I Would use 2209 with a high heat input. For temperatures below -50 C I would use 625 filler material but dillution should be minimized in the root pass to limit the carbon steel dilution in the fusion zone to prevent the reduction in corrosion resistance.
Could you provide a little insight to the 50 degree C limit you wee suggesting for duplex to carbon weld joints.
Alloys 625 / 276 and 22 have been used for this material combination for a number of years in the FGD industry and typically flue gasses are way over this value.
As well for boiler applications 625 is used for service temperatures up to
1200-1300 (gas temp) above this alloy 82 / 182 is used to avoid embrittlrment that is at times seen when 625 is used in this temp range.
Just wondering where the temp limit came from and would be quite interested in investigating this.
Any feed back would be welcome.
Dirk
I was unsure of the service requirements for the application. 625 will typically show better toughness values at temperatures below –50 C than 2209. 2209 will typically have better toughness values at the higher temperature (I think you touched on this when you stated that 625 will be embrittled at 1200-1300). There is also the question of corrosion, which should be considered.
I wasn’t trying to imply that 625 should not be used for elevated temperatures, but if toughness was a consideration 2209 will give better results that 625.
I have also been looking at welding DSS to 4130 and my research agrees exactly with M-Squared, although I have not tested the process. Let us know what works for you. Scott.
M-Squared is right. Anyway, if you want a copy of both the Schaffler and De Long diagrams, which are still good for ordinary purposes, i.e., those not requiring a great degree of sophistication, post (or send me by e-mail) your address and I'll send them to you by ordinary air mail.
Giovanni S. Crisi
Sao Paulo - Brazil
Thanks to everyone. I´ve got the general idea.
Mariano
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