Pete Comment
ANONYMOUS' TABLE 1.
TABLE 2.
* 1) steel of 550MPa and NS56 is equivalent to HY80 grade steel.
- supports for the the pressure hull
- compartments or multiple pressure hulls, and
- strength of the welds used to join sections of the pressure hull.
It is not possible to verify the accuracy of most of the figures. Commenters who know more are invited to supply corrections.
FURTHER READING
See Soryu Submarine Steel Details - Japan Offer to Australia, January 20, 2015
Anonymous and Pete
All submarines have pressure hulls that are made of special steel alloys. In the past the Soviets/Russians bankrupted their economy by also using Titanium alloys. Essentially pressure hulls protect the crew, sensors and engines from excessive water pressure and provide the airtight conditions the crew rely on to breathe.
Pressure hulls need special high yield steel alloys that are flexible enough to:
- contract as water pressure increases (during diving),
- is also strong enough to stop contracting (at maximum diving depth) and
- can then expand as water pressure reduces on the way to the submarine surfacing.
High proof or yield steel for submarines can be measure in pounds per square inch (psi), (eg. HY80 = 80,000psi) or Mega/million pascals (MPa) with this conversion
https://www.unitconverters.net/pressure/megapascal-to-psi.htm.
High proof or yield steel for submarines can be measure in pounds per square inch (psi), (eg. HY80 = 80,000psi) or Mega/million pascals (MPa) with this conversion
https://www.unitconverters.net/pressure/megapascal-to-psi.htm.
A submarine can only go through a limited number of contraction-expansion cycles (especially if it has to deep dive) before it loses flexibility, putting it in danger of metal fatigue.
For a diesel-electric submarine with AIP (eg. a Swedish Gotland class ) on a typical short 12 day mission in the Baltic Sea it may dive and the operate on its Stirling AIP for 10-12 days. It then surface only once = 1 cycle. Perhaps its pressure hull is good for 200 cycles (?) - although its service life is more rapidly limited by hull rust and corrosion - all contributing to a 34 year service life.
For a diesel-electric submarine with AIP (eg. a Swedish Gotland class ) on a typical short 12 day mission in the Baltic Sea it may dive and the operate on its Stirling AIP for 10-12 days. It then surface only once = 1 cycle. Perhaps its pressure hull is good for 200 cycles (?) - although its service life is more rapidly limited by hull rust and corrosion - all contributing to a 34 year service life.
ANONYMOUS' TABLE 1.
Many thanks to Anonymous advising that the pressure hull details in Table 1. below apply to the:
- Swedish (Gotlands, future A26s),
- Swedish designed Australian Collins, and
- future SAAB-Damen entry for the Walrus Replacement competition
In the [cylinder like] design of a submarine, the diameter of a pressure hull significantly effects on many other feature of a submarine [including space, propulsion choices and acoustics]. In terms of diameter (which may sometimes equal Beam) Gotland's are 6.2m, A26s 6.75m, Collins 7.8m and 8m for a SAAB-Damen Walrus replacement. Part outer hulls and sonars on hulls will effect the overall beam of a submarine.
- Swedish (Gotlands, future A26s),
- Swedish designed Australian Collins, and
- future SAAB-Damen entry for the Walrus Replacement competition
In the [cylinder like] design of a submarine, the diameter of a pressure hull significantly effects on many other feature of a submarine [including space, propulsion choices and acoustics]. In terms of diameter (which may sometimes equal Beam) Gotland's are 6.2m, A26s 6.75m, Collins 7.8m and 8m for a SAAB-Damen Walrus replacement. Part outer hulls and sonars on hulls will effect the overall beam of a submarine.
Table
1 Similarity of pressure hull of Swedish and Australian submarines
Submarine
|
Pressure hull steel
|
Proof (or Yield) strength of steel
[MPa]
|
Beam
[m]
|
Diameter of pressure
hull
|
Estimation
|
Gotland
|
Weldox700EM
[1]
|
700
|
6.2
|
Same
|
In A26, sound absorption rubbers (thickness 100mm)
are presumably attached on the surface of prssue hull. In A19, no sound
absorption rubbers are attached, or very thin rubbers are used.
|
A26
|
700
|
||||
Collins
|
700
|
7.8
|
Same
|
Difference in beam is due to difference in
position or shape of flanl arry sonar.
|
|
SAAB-Damen
Walrus Replace-ment |
700
|
8
|
[1] Weldox is old brand name of Strenx.
-----------------------------------------------------------------------------------
Below is a broader comparison of Chinese, Russian & Western Submarine Pressure Hull Steel Strengths originally published on July 20, 2015. Note the Swedish measure Weldox700 and Australian BIS 812 EMA in both Tables with both at 700MPa equivalent to HY100..
-----------------------------------------------------------------------------------
Below is a broader comparison of Chinese, Russian & Western Submarine Pressure Hull Steel Strengths originally published on July 20, 2015. Note the Swedish measure Weldox700 and Australian BIS 812 EMA in both Tables with both at 700MPa equivalent to HY100..
TABLE 2.
YS = Yield Strength or proof stress. HY = High Yield
YS | US | UK | France | Germany | China | Russia and India | Japan | Australia | Sweden |
550MPa | HY80 | Q1N | 1.3964 | India DMR- 292 # | * 1) NS56 | ||||
590MPa | 60HLES | 921A TA5-A | AK-25 48-OT3 | ||||||
630MPa | 1.3974 | ||||||||
690MPa | HY100 | Q2N | AB-2 | * 2) NS70 | |||||
700MPa | 80HLES | BIS812 EMA | Weldox 700 | ||||||
785MPa | 980 | AK-29 | NS80 | ||||||
890MPa | HY130 | 100HLES | *4) Ti80 | AB-3? | NS90 | Weldox 900 | |||
980MPa | AK-33 | ||||||||
1075MPa | AK- ?? | ||||||||
1178MPa | HY156 |
* 3)
NS110
|
* 2) steel of 690MPa and NS70 is equivalent to HY100 grade steel.
* 3) steel 1078MPa and NS110 is equivalent to the HY156 grade steel.
The Table is from towards the end of Japanese Document "High-tensile steel Summary of national submarine" or Summary of High Tensile Steel for Submarines by Country 2013 http://seesaawiki.jp/w/doramarine/ .
---
---
COMMENTS FOR TABLE 2.
- supports for the the pressure hull
- compartments or multiple pressure hulls, and
- strength of the welds used to join sections of the pressure hull.
It is not possible to verify the accuracy of most of the figures. Commenters who know more are invited to supply corrections.
FURTHER READING
See Soryu Submarine Steel Details - Japan Offer to Australia, January 20, 2015
Anonymous and Pete
7 comments:
Hi Pete,
It seems that the beam for the A26 is 6.75 m, see the fakta section in the link (in Swedish check for bredd).
/Kjell
Thanks /Kjell
For the 6.75m correction. I will change the text accordingly.
And the FMV link http://fmv.se/sv/Projekt/Ubat-typ-A26/ you have identified is a very useful source in itself.
Regards
Pete
Hi Pete
Beam of 6.75m for A26 is correct. This data is based on FMV (http://fmv.se/sv/Projekt/Ubat-typ-A26/A26-del-for-del/).
Beam of 6.4 for A26 is based on (https://en.wikipedia.org/wiki/A26_submarine#cite_note-datasheet-3) referred to http://www.kockums.se/PageFiles/736/A26_Datasheet.pdf which is Kockums under TKMS.
Then, pressure hull of A26 is different from Gotland.
Regards
Hi pete
Check this out from India
India signs $3 billion contract with Russia for lease of a nuclear submarin
https://www.defensenews.com/global/asia-pacific/2019/03/08/india-signs-3-billion-contract-with-russia-for-lease-of-a-nuclear-submarine/
Maybe Russia should start talking to India on selling them the Akula class SSN.
Hi Nicky
1. I was writing my Akula lease article yesterday but decided to not be like the herd and to publish on Monday.
2. I would guess non-proliferation conventions (the NPT?) argue against actual sale of nuclear submarines and nuclear weapons.
So leasing a Russian submarine (by an already nuclear submarine building India) is more or less "legal"
Regards
Pete
Hi Pete,
I found a document describing the Polish Orka replacement program PULASKI POLICY PAPER: Poland’s ‘Orka’ submarine programme. Part 3. The A26 submarines – Swedish Offer maybe it can be of interest, and of cource there is a part 1, HDW Class 212A/214 and a part 2, Scorpène.
/Kjell
Thanks Kjell [at 9/3/19 10:19 PM]
An excellent paper on the A26 entry in the Polish Orka competition.
I'll use it in a few days for an article.
Regards
Pete
Post a Comment