Dear Bagesh,
Some information for your reference.The original material NAS 144M is a S.S with higher Nickel and Mo with enhanced pitting corrosion resistance in high chlorine environment. 316L can not be a substitute for this alloy, just because the composition (18Cr-8Ni-2Mo) would not sustain long in high chlorine environment. During the manufacture of acrylic esters and other products if chlorination is apart of the process then it would harm 316L seriously.
If NAS 144M is difficult to procure then, Avesta 254SMO or Allegheny Ludlum AL-6XN, or NAS 254NM could be the nearest alternatives. These alloys may be 15-20% more expensive compared to NAS 144M, but are available as ASTM/ASME grades, which makes it easy to procure all round the world.
I would like to query the selection of Hastelloy-C-276.This alloy is no doubt a good alloy in a very high chlorine environment, but it costs a fortune, both as raw material and welding consumable. This alloy is recommended to fight dew point and high temperature corrosion, Flue Gas Desulphurization Units, where the chlorine content could be easily in the range of 20000 ppm or more.
Between 1997-1999 I worked as Procurement, Welding and Inspection Q.C for an acrylic Acid/Ester project in S.E Asia. A Jump from Stainless to Hastelloy is easily recommended by suppliers, especially, for control valves, measuring devices and many other items,however the cost of change of material may be prohibitive.
I would say, take a rationale look at the material selection and for the said environment, assess the corrosion rates for each material, service life of the plant then make your final selection. If you require, take the help of metallurgists or welding personnel well versed with these materials.
Thanks.
Pradip Goswami,P.Eng.,IWE
Welding & Metallurgical Specialist & Consultant
Thank you all for your inputs,
We have written a technical clarification to client about the details and knowhow reason for the use of this material against the said service, however we have decided to go with the Hastelloy C276 for these services.
We have also contacted Nihon Yakin of Japan, but presumably they have obsolete this alloy and are offering higher grade equivalent to Hastelloy C276..
Will put the same when I receive the inputs from the Vendor and client.
Thank you once again.
===================
Bagesh Kumar
Seoul 135985
===================
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Stefan SAUCIUR
Sent: Friday, November 05, 2010 11:23 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:8098] (NAS144M) equivalent of this material??
Stefan --- On Fri, 11/5/10, Harish Kannepalli <harishkannepalli@gmail.com> wrote:
From: Harish Kannepalli <harishkannepalli@gmail.com>
Subject: Re: [MW:8086] (NAS144M) equivalent of this material??
To: materials-welding@googlegroups.com
Date: Friday, November 5, 2010, 12:57 PM
Dear Mr. Bagesh, Thank you for introducing some new material to me as well as group. This material is a patented one almost equivalent to 316L. Please find the link attached for further info. http://ip.com/pdf/patent/US6966973.pdf 2010/11/5 Bagesh <bagesh.kmr@gmail.com> I have been doing a project in Korean peninsula and certainly while browsing through the piping material specification I have found NAS144M material and it has been used for the service of ACRYLIC ACID, REACTED GAS and ESTERS. The P T Rating for these services is 150 Rating. When enquired with vendors they don’t have any clue until we supply the correct material property, the contract MSD has shown 254SMO as the property of this material, For the reference we have used SS316L for such services in other projects, but the client have rejected our request and they just resist on the material property, Could any one have some brief on the said subject or equivalent ASTM spec or Its UNS no.. I do not have any other things to share on the same. Regards =================== Bagesh Kumar =================== --
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