Nace Standard and PWHT

Hi,

Which NACE std is specified by customer, i assume NACE MR0175.

SS material grade?, Design code?,

Sometimes customer spec mandate PWHT even Hardness falls below 22HRC, sec 5.3.2 of NACE MR0175 talks about PWHT of martensitic stainless steel but for stabilized grade (SS347 or SS316L) is generally not required, again please specify all design parameters for more information.

Regards, Manpreet Singh

Dear Mr. Singh

Thanks a lot for your reply. Nace standard is according to the MR0175. In some equipments, SS grade is 316 L, and other equipments are 304L. Design code is based on ASME. Design pressure and temperature are 8.5 barg/Full Vacuum and 210'c, respectively. Please don't hesitate to ask me another information.

Kind Regards,

Hi,

Thanks for prompt feedback, still got few questions-

Is it SS 316L/304L cladded CS vessel? if yes then please review Sec Viii div 1, UCS-56 which would require PWHT for base metal thickness above 32mm.

If only SS material, then please review UWL which covers PWHT requirement for alloy material.

also note that if service is considered "lethal" per definition "UW-2" then PWHT is required regardless of other facts.

Also note that if PWHT is carried out then a suitable consumables and temp. range are followed to avoid sensitization of these material.

Regards

Manpreet Singh

Dear Mr. Singh

Thanks for your kind cooperation. Your answers have been very suitable. One of my equipment operates in the lethal situation. I have studied the UW-2, but in this part have been noticed carbon steel and low alloy material should be PWHT. I think SS is classified in high alloy material. What's your idea about that?

Kind Regards.

H.I

Hi Hamed,

I asked u whether it is SS cladded CS vessel or SS vessel, i assume SS vessel, then UW-2 (lethal service) does not mandate PWHT,

Table UHA-32 (PWHT requirement for High alloy steels) state that "PWHT is neither required nor prohibitted for Pno. 8 materials"

hence PWHT is not required unless your material service condition stipulate requirement (please see service expert)

alos review appendix A, A-350 of ASME sec ii part D for guidance,

Regards

Manpreet Singh