Hardness of Carbon Steel Ring Joint Gaskets 1

[Engdoitbetter]

Good morning,

I've read on ASME B16.20 that for carbon steel ring joint gaskets a maximum hardness is prescribed (lower than 90 HB for soft iron, lower than 120 HB for low carbon steel). It is also recommended (but AFAIK not mandatory) that gasket hardness be lower than flange groove's.
Given these requirements, could you help me answer the following questions:

a) is A105N a suitable material for ring joint gaskets? I read it is a medium carbon steel (C about 0.3%).
b) If so, should a max hardness be prescribed or not for this material?

Thank you in advance for your helpful replies.

Best regards,

Stefano

 

[TWP]

You should'nt use A105. This material has a hardness of approx. 140 HB or higher. Doesn't meet the max. allow. hardness of 120 HB for the Low carbon Steel.
Hardness of ring joints shall be eesentially lower than mating flanges. Difference at least 25 HB! (advise/ for proper functioning/ sealing).

Good luck!

 

[Engdoitbetter]

Thank you very much TWP for your kind reply.

Regards,

Stefano