In the correctly gradual process, since 2014, to select Netherlands' 4 Walrus replacement subs the shortlist (3 contenders: Sweden, France and Germany) are fighting it out on many levels. One level is the relatively arcane choice of less magnetic pressure hull steel.
By contrast Australia only gave itself less than 18 months (for political vote reasons) from shortlist stage to picking the winner.
Below the article of January 19, 2021 two particular comments were:
A. Anonymous's (for the French or Swedish contender?) comment of January 29, 2021 at 6:01 PM:
[Germany’s? ] Regarding "Non-magnetic stainless [steel] Nitronic 50, well for it to be truly ‘non-magnetic’ it needs to be annealed which means no strength, which means...nope, not useful for the application at hand. Incredible hard to weld, solidification cracks. And there are other ways to manage magnetism too; degaussing.
Wonder why Nitronic, which I think is inherently an American steel is offered by the Germans?"
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Against which Anonymous B. countered:
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B. Another Anonymous (for Germany?) at January 31, 2021 at 12:17 PM:
(1) 1.3964 is material number and Nitronic 50 is bland name [that hyperlink explaining]:
“1.3964 is the Werkstoff number for a more highly alloyed austenitic stainless steel most commonly known as Nitronic 50. The Werstoff designation was developed by the German standards body DIN, with the term Werkstoff translating approximately to ‘material’. It is also known as XM19, as used in ASTM A182, ASTM A276 and ASTM A479, alongside the unified numbering system caption of UNS S20910. Nitronic 50 is a trademark of AK Steel Corporation.”
(2) Magnetism of 1.3964 is extremely small and annealing is not needed.
[See this link] page 2/2, figure of “Magnetic permeability”
(Relative) magnetic permeability (ur) is 1.0033, while ur for iron is 200000 as shown in wikipedia.
(3) Effect of annealing on magnetism of Nitronic 50 is neglectable.
[See this link] , page2/2, table of “PHYSICAL PROPERTIES”, Magnetic Permeability: (@ RT, 200 oersted):
(Relative) Magnetic Permeability of Annealed or “Super” High Strength (of Nitronic 50) is ca.1.004”
ibid MAGNETIC PERMEABILITY: Nitronic® 50 does not become magnetic when cold worked. The magnetic permeability of the alloy remains low even at cryogenic temperatures to below -400˚F.
Pete Comment
So there you have it. After 6 years the Dutch future submarine selectors thoroughly continue the mage task deciding the $Multi-Billion merits of the 3 contenders – maybe by 2022.
If only Australia's future submarine selectors had also been allowed 8 years (instead of less than 18 months) by their political masters to coolly select the winner of 3 contenders.
Note what I wrote on April 25, 2016. But the selection milestone in Australia was the 2016 Federal Election. Racing towards selection of France was essential for the ruling Coalition to win votes in South Australia. So Australia's Prime Minister cut the selection from a shortlist of 3 to just one winner, on April 26, 2016.
Pete