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 hullsprotect 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 6.4m, 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 6.4m, 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 | 6.4 | |||
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.
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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..
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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 |  Russiaand 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