SS dual grade 1

[carloz]

I'm working for a Petrochemical Indutry involed in vlaves production: I would be happy if someone can explane to me the meaning of "dual grade" for SS material (e.g. 316/3163L) and whether some specs/ASME code decalre the material as dual grade or not.

Thanks

Carlos

 

[TD2K]

Dual grade has the advantages of low carbon 304 SS in avoiding weld sensitization during welding where carbon can precipitate the chromium out during welding as chromium carbide BUT has the higher strength of conventional 304 SS

 

[carloz]

Thanks for your quik reply, but I have another question: what is the specification that declare the "dual grade"?
This because of our customer has required to us this materials and we can suppy the SS having the chemical composition as per "L" grade and the mechanical proprieties as per 304 (slighty higer than L grade).
From the quality point of view, how we can manage this matters?

Thanks

Carlos

 

[0707]

Carloz

I suppose that TP304 H is an example of dual grade SS. TP 304 has a Carbon content of 0.08 max. TP 304L has a Carbon content of 0.035 max. TP 304 H has a carbon content of 0.04 min. and 0.10max. Other examples are TP316H, TP321H, 347H and 348H. Stainless steels of H grade have higher corrosion resistance at high temperatures than the other grades.

Luis Marques

 

[weldtek]

The manufacturer declares a material 'dual grade' based on chemistry and mechanical testing. You can have a material certified as 304/304L or 304/304H, but, not 304L/304H.