Duplex Dished Head

[Angsi]

Code: ASME Sect VIII, Div 1

Is it normal to request for a head forming test piece for Duplex materials i.e. semi ellip from a flat plate?

What are the concerns? Does cold working affect mechaical and corrosion properties of the duplex material?

Thanks in advance.

 

[bmoorthy]

As per ASME Sec VIII div 1 Duplex grades (31803, 32750) does not require Heat treatment after cold forming. Refer UHA.

Generally the user specifies the heat treatment requirement (Specifying conditions when they want heat treatment done).

So long as hardness is less than 31 HRC there should not be any problem after forming. Now where did i get this 28 HRC from?

That is from our company standard. Based on the base material requirement.

You may want to have a look at NACE MR 0175

Also you may want to check Austenite and ferrite balance. these recommendations are to come from corrosion experts.As per code there are no specific requirement regarding heat treatment after cold forming.