High Mn content on ASTM A351-2003 grade CD4MCu
High Mn content on ASTM A351-2003 grade CD4MCu
(OP)
I have received a valve casting per ASTM A351-2003 grade CD4MCu. I performed Positive Identfication Inspection (PMI) and found all the elements meets the ASTM specification with exception of Mn%. Instead of max 1% Mn material that I received has Mn 1.5 % - 2%. Manganise should improve the mechanical strength of the cating but, I am not sure if it will effect the chemical resistance of the material or the macro structure of the material.
As a note: forged grade F51 has 2% Mn.
As a note: forged grade F51 has 2% Mn.





RE: High Mn content on ASTM A351-2003 grade CD4MCu
Regardless, you have a nonconformance of the valve material per ASTM A 351 that must be dispositioned before use. Did you or can you obtain a material test report for the valve body material? If not, I would try to obtain a small sample from a noncritical location on the valve body for chemical analysis to verify the PMI results. I have seen where PMI results were not totally correct and further chemical analysis was required.
RE: High Mn content on ASTM A351-2003 grade CD4MCu
As far as your concern, I am not too worried about the Mn level itself. My concern would be realted to the overall austenite/ferrite balance and checking to make sure that it correct.
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