In reality it's quite difficult to get E-347 welding consumables, impact tested up to -196 Dec C, with consistency. Usually this consumable as well as both SS 321 & SS 347 are more commonplace for high temperature services while 304L, 316L are more preferred base materials for lower temperature services.
However I would not go into the debate of selecting SS 321 for Cryogenic Service. It's the designer's call.
Coming back to the issue of welding consumables you'll have problems in consistency of impact strength for E-347, due to high Ferrite(8FN Min as mandated by AWS & other standards).E-347 is definitely preferred choice for welding SS 321 if the intended service is at high temperature.
Under the present circumstances in order to meet consistent impact @ -196 Deg C, your best bet should be E/ER-316/316L or 316LN, which may come in dual certified grade and impact tested conformably @ -196 Deg C.
Please see some extracts from SFA 5.4 and some attached literature for general guidance. As per the attached literatures from reputed consumable manufacturers 347 SMAW weld deposits would always have lower notch toughness values @-196 Deg C.
Also Mr Girotra is copied also. Being in the welding consumable industry for many years, he may be able to enlighten everyone on this issue. This is –not for any commercial considerations.
Thanks.
P.Goswami.P.Eng, IWE.
Welding & Metallurgical Specialist
Linkedin: https://www.linkedin.com/in/pradip-goswami-2999855/
Email:pgoswami@quickclic.net,pradip.goswami@gmail.com
A7.23 E316L. This composition is the same as E316, except for the carbon content. The 0.04 percent maximum carbon content of weld metal deposited by these electrodes reduces the possibility of intergranular carbide precipitation and thereby increases the resistance to intergranular corrosion without the use of stabilizers such as niobium or titanium. These electrodes are used principally for welding low-carbon, molybdenum-bearing austenitic alloys. Tests have shown that 0.04 percent carbon limit in the weld metal gives adequate protection against intergranular corrosion in most cases. This low-carbon alloy, however, is not as strong at elevated temperatures as Type E316H. This classification with maximum ferrite content of 2 FN has traditionally been the choice for welding Types 304 and 316 stainless steels for cryogenic service at temperatures down to –452°F [–269°C].
A9.3 Impact Property Tests for Welds Intended for Cryogenic Service
.
A9.3.2 Austenitic stainless steel weld metals usually are not fully austenitic but contain some delta ferrite. Delta ferrite is harmful to cryogenic toughness. However, fully austenitic weld metal has a greater susceptibility to hot cracking (see A6). It has been found that such weld metals require judicious compositional balances to meet the 15 mils [0.38 mm] lateral expansion criterion even at moderately low temperatures such as –150°F [–100°C].
A9.3.3 Electrode classifications which can be used if special attention is given to the weld deposit composition content to maximize toughness are E308L-XX, E316L-XX, and E316LMn-XX. Published studies of the effect of composition changes on weldment toughness properties for these types have shown the following:
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From: prem_nautiyal@rediffmail.com [mailto:prem_nautiyal@rediffmail.com]
Sent: August 17, 2017 3:52 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:26725] ER 347 Vs E347 CVN impact values
There is No IGC or Ferrite number requirements.
However the welding consumable manufacturer have opined that due to ferrite content in SMAW process they cannot guarantee impact at such low temperatures at minus 196 degree Ceclius.
On Thu, 17 Aug 2017 11:59:26 +0530 "'james gerald' via Materials & Welding" wrote
> I suppose there is some problem with the selection of material, SS 321/347, which contains Titanium / Niobium which are Ferrite formers and for -196degC service why do you need IGC control. Try 304LThanks & RegardsJ.Gerald Jayakumar0091-9344954677
From: Pandithan
To: PREM SHANKARDUTT NAUTIYAL
Cc: materials_welding
Sent: Thursday, August 17, 2017 10:12 AM
Subject: Re: [MW:26723] ER 347 Vs E347 CVN impact values
For TIG, try with ER321
On 16-Aug-2017 11:54 PM, PREM SHANKARDUTT NAUTIYAL wrote:
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Dear friends
A vessel will be fabricated as per EN 13445 - 2014 edition.
As per contract impact test is mandatory at minus 196 degree Celsius with Min. Impact value of 40J.
Base material is SS 321.
Thickness ranging from 10mm to 20mm.
Two separate PQR are being conducted as per EN ISO 15614-1.
1. Complete TIG with ER 347 with controlled heat input less than 1KJ/mm
PQR coupon thickness was 14mm.
= impact values are coming on weld avg 30J - Failed.
HAZ = @ 55 J and passing.
Now trying PQR with other brand.
2. Complete MMAW = E 347 - Here consumable manufacturer in India have regretted impact properties at minus 196 degree Celsius.
Both TIG and MMAW consumables are having @ 8 FN.
Then why MMAW Consumable manufacturer in India have regretted impact properties at minus 196 degrees Celsius for MMAW process E347 ?
Difficult to understand !
Regards
Prem Nautiyal
IWE
PREM S NAUTIYAL
CELL : 9769316004
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PREM S NAUTIYAL
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