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[MW:19860] Duplex microstructure

By Materials & Welding
Dear members,

Duplex structure in Duplex stainless steel [DSS] is 50% Austenite and 50 ferrite appx. The ferrite mentioned here is alpha ferrite or delta ferrite?. Because in many of the solidification diagram for DSS refered in this forum, the alpha ferrite symbol is used. 

Sigma phase conversion of delta ferrite is one of the major issue in DSS, that is why ASME code restrict its use below 350degC.

Please claify...

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With Regards,
Sudharsan

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