[MW:24618] RE: 24612] Lethal service requirement

Hi Sachin,

I hope API RECOMMENDED PRACTICE 945, Avoiding Environmental Cracking in Amine Units is refereed in the drawings. This is an essential document for amine service .As per this document use of austenitic S.S (304L/316L) clad steel is often done for amine plant equipments, for specific set of design conditions. That’s well taken care of in the details provided below.

As regarding fabrication, PWHT requirement is governed by the thickness of the backing material Carbon Steel, for regular amine service. From that aspect had this been a normal Amine vessel with 316L clad, exemption from PWHT would have been possible for 8 mm of C.S wall thickness.

Sec-VIII, UW-2 refers to mandatory PWHT for C.S/LAS vessels in “Lethal Service” . The same concept is applicable for clad vessels also, involving lethal service. Please see the latest ASME Code interpretations as below. Note there are two answers. My interpretation is to go with tracking No 9980 (since it’s latest and more detailed)

Hope this would help.

Thanks.

Pradip Goswami, P.Eng,IWE
Independent Welding & Metallurgical Engineering Specialist & Consultant.
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299

pgoswami@quickclic.net

pradip.goswami@gmail.com

https://cstools.asme.org/Interpretation/SearchInterpretation.cfm
https://cstools.asme.org/Interpretation/InterpretationDetail.cfm?TrackingNumber=946
https://cstools.asme.org/Interpretation/InterpretationDetail.cfm?TrackingNumber=9980

From: sachin.sankhe@rediffmail.com [mailto:sachin.sankhe@rediffmail.com]
Sent: Friday, April 01, 2016 1:25 PM
To: materials-welding@googlegroups.com
Subject: [MW:24612] Lethal service requirement

Dear Friends,

Need your opinion on below

Equipment

Columns

Design Code

ASME SEC VIII Div.1

Process

High Wet H2S service(NACE)

Wet Amine service

Very Toxic

Lethal(ASME SEC VIII, UW-2)

Metallurgy/Thk

Base Metal MOC=SA516 Gr.70

Thk=8mm

Clad MOC=SS316L

Clad thk=3mm

Problem

Is PWHT mandatory for clad vessel for above process condition?

For lethal service is PWHT not mandatory for clad vessel as per Table UCS56.1 Note (e)

Regards

Sachin Sankhe

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