For TIG, try with ER321
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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:pgos...@quickclic.net,pradip....@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
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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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Another possibility is 16-8-2. Although developed for welding for high temperature applications, the weld metal has shown acceptable weld metal impact properties at cryogenic temperatures. This is briefly addressed in the following:
Hope this might help.