PWHT of Monel 400

[stopsunset]

Can anyone give me any insight into the Brinell Hardness requirements for Monel 400 after PWHT for pipe? Is it in the range of 160-185 BHN? I also can not find any information regarding at what hardness levels does Monel 400 become susceptible to cracking. I have seen some documentation suggesting it may be in excess of 140 BHN. Thanks

 

[cap1a79]

In case the type of the cracking is sulfide (H2S) stress corrosion cracking, maximum hardness limit for monel (UNS N04400) is 35 HRC.

Refer to below reference.

1) From NACE MR 0175 / ISO-15156-3, table A.13

"UNS N04400 and UNS N04405 shall have a maximum hardness of 35 HRC."

2) From NACE MR 0103, clause 14.1.1.6

"Wrought UNS N04400 and N04405, and cast ASTM A494 Grades M35-1, M35-2, and M30C
shall not exceed 35 HRC."



Lee SiHyoung,
WorleyParsons Oman Engineering,

 

[stopsunset]

Thank you Lee