Hi Mohammed,
True both DSS (31803) and SDSS(32750) are classified under P No 10H Gr1 in ASME Sec-IX. However in QW-422, under ISO 15608, Group listing , DSS (31803) is Group 10.1 while SDSS(32750) is classified as Group 10.2. The proper explanation of Gr 10.1 and 10.2 is given the attachment. Alloy 31803 and alloy 32750 is not the same. This possibly would be addressed in subsequent amendments of Sec-IX Code.
ASME Sec-IX code is applied typically for welding qualification in potable water plant to Nuclear power plant (just a statement to highlight the wide application range) . One code can't address the concerns of all the industries. In many instances specific standard, design requirements are applicable .Duplex is one those alloys, which is fabricated to specific design requirements. Should you want to know about this read through API-RP-938Cor other related specifications for offshore oil and gas industries.
Seawater corrodes all alloys. Only a few could sustain these environments , such as DSS/SDSS, Nickel alloys and Titanium.
In addition to ASME Sec-IX qualification tests, Hardness, Critical Pitting Temperature(CPT) to ASME G48A are mandatory. For DSS if the CPT test is typically 30 Deg C/24 hrs for SDSS it would be 40Deg C /24 hrs or more. Do you have these tests in PQR testing.
Hence should you would decide to weld SDSS 32750 with GMAW ER 2209-16 filler ( which matches the chemistry of DSS 31803), I'm sure the service induced failures are only a matter of time.
Perhaps you need to get the concurrence of your client before you proceed for welding.
It would be good to hear about the outcome.
Thanks
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Specialist
Ontario, Canada
pgoswami@quickclic.net
pradip.goswami@gmail.com
pradip_goswami@yahoo.ca
-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of S.Mohammed
Sent: Wednesday, March 26, 2014 1:17 PM
To: materials-welding@googlegroups.com
Subject: [MW:20416] RE: 20411] DSS vs SDSS welding.
dear sir,
i agree with weld.metal chemistry.
service is seawater line highly corrosive.
But as per ASME,there is same A number 8 is provided for both DSS n SDSS. And P.number also 10H and group also same 1.
its looks like a limitation of ASME or it is more liberal about metal classification.
in what code or standard basis should i say to my construction for new WPS.
regards,
*****************************************************************************************************************************************************************************************************************************
No,
31803 is DSS while 32750 SDSS. Duplex alloys are used for very demanding applications. Hence the weld metal must match or exceed the requirements of base metal properties. Hence a new PQR would be advisable.
What're the design and service requirements by the way??
You need to consider all of these before proceeding for any welding on DSS or SDSS.
Appreciate your response.
Thanks.
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Specialist
Ontario, Canada
pgoswami@quickclic.net
pradip.goswami@gmail.com
pradip_goswami@yahoo.ca
--------------------------------------------------------------------------------
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of S.Mohammed
Sent: Wednesday, March 26, 2014 6:13 AM
To: materials-welding@Google groups.com
Subject: [MW:20411] DSS vs SDSS welding.
dear all,
ASME IX,B31.3.
WPS available for SA 182 F51 UNS 31803 P.10H with GMAW ER 2209-16 can be utilsed for welding SA 182 F53 UNS 32750 P 10H?( thk range is covered by WPS.).
what are the metallurgy concern to be require?.
regards
mohd.
--
To post to this group, send email to materials-welding@Google groups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.BlogSpot.com/
http://www.LinkedIn.com/groups/Materials Welding-122787?home=&gid=122787&trk=anet_ug_hm
The views expressed/exchanged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout
No comments:
Post a Comment