SA 516 Gr70N of 12 thk palte require PWHT? 1

[ramesh349]

Hello

i am working on a vessel. it is a methanol storage vessel with a material of SA 516 Gr.70N + NACE MR0103 and H2S is applicable for plate material.
I am not able to find out whether PWHT is require or not??. and also vessel is a methanol storage vessel(Wet H2S) is it comes under lethal service?

Please clarify me.
Thanks in advance

 

[metengr]

Did you ask the owner of the vessel for the ASME data report?

 

[ramesh349]

Client mentioned it is vendor scope.

 

[metengr]

Are you designing this vessel or repairing it????

 

[SnTMan]

ramesh349, it is entirely the client / owners responsibility to inform if the vessel is in lethal service.

As to PWHT, NACE MR0103 should tell you that, in my experience, any CS vessel in wet H2S will be PWHT, and likely full RT as well.

Regards,

MIke

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[ramesh349]

Hello Mike,

Thank you for your reply,

Can please explain me detail why PWHT & Full RT required?

I complited design with Spot for both dish and shell and with out PWHT.

Mainly because the Plate thickness is 12 mm(External pressure governing) and also considered no lethal condition. Since client does not mentioned anything about service.

Please clarify me, whether i am correct or not?


Mr. metengr.

I am designing the vessel.

Thnk you,
Ramesh Kuamr

 

[SnTMan]

ramesh349, I am no metallurgist, but the short answer is the effects of the service on the materials of construction. You very much need to read NACE MR0103 and gain an understanding of it and perhaps referenced literature as well.

You very much need to read and understand project & contract documents prior to completing a design.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[metengr]

ramesh349;
You have two criteria to meet regarding PWHT, the requirements in NACE MR0103 and ASME Section VIII, Div 1 UCS. If both exempt PWHT based on your design conditions you are not required to PWHT. If either requires PWHT based on starting material condition, forming strains or welding, PWHT is required.

 

[r6155]

See NACE MR0103 2016 5.1.2 It is the end user’s (or the end user’s agent’s) responsibility to ensure that a material is
satisfactory in the intended environment.


ramesh349: read MR0103 in full, and be careful with welding.

Regards
r6155

 

[pradipgoswami]

Hi Ramesh349,

Methanol is generally considered to be toxic and lethal. This PWHT is mandatory as per UW-2, DIV-1.

http://www.methanol.org/wp-content/...Selection-for-Neat-Methanol-Service_FINAL.pdf

MR-0103-20161, Clause 3.1.7.2 mandates:Weldments in carbon steels listed as P-No. 1 material in Section IX of the ASME BPVC shall be produced using one or more of the methods outlined in NACE SP0472 to prevent excessive weldment hardness.

NACE SP0472 talks about hardeness control to 200 HBW in weld and HAZ, through application of PWHT( as one of the suggested methods).

To summarize:
Vessel requires PWHT & Hardness Control.

You may be the designer, however as explained by the previous respondents to this query, the client(end user)needs to specify the Toxicity and other process details related to Methanol, in the vessel data sheet.

Thanks.


Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.

 

[ramesh349]

Thank you very much for your valuable suggestions.

first: As per above all comments i am going to client to confirm about Service condition.

Second: i checked with USC-56 it is ok with UCE. Only i have to check the service limitations with client. that is what i understand from your responce above.

Third: as per MR0103
The WPS no. 034, 026, 043 and 012 shall not be considered for PWHT since Austenitic Stainless steel(SS 316L) involved.

WPS no. 41, 010 A and 002 applicable for structural material and hence NACE not applicable for this. NACE applicable for some piping classes such as A15T, AS L2, F5T GRW5T.

So the only WPS under consideration is WPS 005 and WPS 046.

Please note that WPS 005 & WPS 046 will be used for welding SA 106 Grade B / SA 105 / and SA 516 Grade 70 materials.

Minimum Tensile strength are above 480 MPa for SA 105 and SA 516 grade 70.

NACE RP0472 not applicable for material having tensile strength above 480 MPA as per clause 1.2 of NACE RP 0472. Refer below point from standard.

So PWHT not applicable for SA 105 and SA 516.





1.2 This standard covers only carbon steels classified as P-1, Group 1 or 2.
These classifications can be found in the ASME Boiler and Pressure Vessel Code, Section IX,' ASMEíANSI B31.3 Code for Pressure Piping, or API Standards 620 and 650. It excludes steels over 480 MPa (70,000 psi) minimum specified tensile strength. Other materials may be vulnerable to cracking, but these materials are outside the scope of this standard.





As per Table 1, HIC in HAZ can be avoided by three options. Either by base metal chemistry control or PWHT or Hardness survey during PQR. Hard ness shall be less than 248 HV. Refer below table.

Please note that Hard survey carried out for all the concern PQRs and the maximum hard ness is less than 248HV .



Since Hardness survey carried out during PQR stage and found that the maximum value is less than 248HV , PWHT not required to avoid HIC.



Once again thank you for your feedback about my query.