Pakistan working on Nuclear Submarine ?

[Dr Gupta]

@Penguin Could you enlighten us on the special grade steel used for a nuclear submarine's hull?

You think Pakistan could manufacture it? or would they simply import it from China which is far easier to do so.

 

[Penguin]

@Penguin Could you enlighten us on the special grade steel used for a nuclear submarine's hull?

You think Pakistan could manufacture it? or would they simply import it from China which is far easier to do so.

You would want a submarine hull to be made out of a very strong alloy, but, non-magnetic & highly corrosion resistant. A predominantly non-ferrous alloy would be preferable.

Steel for the production of submarine hulls, which is characterized in that the chemical composition thereof comprises, by weight percent:

• 0.03%≦C<0.08%;
  
• 0.04%≦Si≦0.48%;
  
• 0.1%≦Mn≦1.4%;
  
• 2%≦Ni≦4%;
  
• Cr≦0.3%;
  
• 0.3%≦Mo+W/2+3(V+Nb/2+Ta/4)≦0.89%;
  
• Mo≧0.15%;
  
• V+Nb/2+Ta/4≦0.004%;
  
• Nb≦0.004%;
  
• Cu≦0.45%;
  
• Al≦0.1%;
  
• Ti≦0.04%;
  
• N≦0.03%;

• the remainder comprising iron and impurities resulting from production, boron being an impurity with a concentration of less than 0.0005% and P+S≦0.015%, the chemical composition satisfying condition 410≦540�C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30.ltore- q.460.

The inventive steel has an essentially martensitic or lower bainitic structure comprising at least 90% martensite or lower bainite, at most 5% residual austenite, at most 5% ferrite.

The steel has a yield strength of between 480 MPa and 620 Mpa and a Charpy toughness V, KCV at -60� C. of more than 50 J.

Now, I have no idea what this al means exactly ;-)

You might find these intersting read.
http://gentleseas.blogspot.nl/2015/01/japan-offer-to-australia-soryu.html
http://gentleseas.blogspot.nl/2015/04/submarine-steel-strength-implications.html
http://www.dtic.mil/dtic/tr/fulltext/u2/616980.pdf

 

[Nilgiri]

@Penguin Could you enlighten us on the special grade steel used for a nuclear submarine's hull?

You think Pakistan could manufacture it? or would they simply import it from China which is far easier to do so.

It would be cheaper for them to import from China. They could possibly make it themselves but it would add a lot to the overall cost since its a one time job whereas China has economies of scale in steel production to begin with.

 

[SQ8]

It would be cheaper for them to import from China. They could possibly make it themselves but it would add a lot to the overall cost since its a one time job whereas China has economies of scale in steel production to begin with.

The most important rule in Pakistani procurement is what you have spelled out. If Pakistan can get something cheaper from abroad without hassle and with a guarantee that it can keep it running without sanctions.. it will get it.
The ONLY thing it tries to make on its own is something that it cannot get or has but the logistics are prey to diplomacy.

 

[_NOBODY_]

Its beyond the mean of the country
No way China is giving away its precious new SSBN or SSN designs

China will soon have Type 96 SSBN and since they will be having this beast than why can't they provide us Type 94 SSBN ? I think Pakistan is not willing to induct it because once SSBNs are spotted they are very vulnerable and those ballistic missiles equipped with nuclear warhead inside SSBNs would backfire and Chinese nuclear submarines are very noisy(expect the latest ones).

 

[Dr Gupta]

You would want a submarine hull to be made out of a very strong alloy, but, non-magnetic & highly corrosion resistant. A predominantly non-ferrous alloy would be preferable.

Steel for the production of submarine hulls, which is characterized in that the chemical composition thereof comprises, by weight percent:

• 0.03%≦C<0.08%;
  
• 0.04%≦Si≦0.48%;
  
• 0.1%≦Mn≦1.4%;
  
• 2%≦Ni≦4%;
  
• Cr≦0.3%;
  
• 0.3%≦Mo+W/2+3(V+Nb/2+Ta/4)≦0.89%;
  
• Mo≧0.15%;
  
• V+Nb/2+Ta/4≦0.004%;
  
• Nb≦0.004%;
  
• Cu≦0.45%;
  
• Al≦0.1%;
  
• Ti≦0.04%;
  
• N≦0.03%;

• the remainder comprising iron and impurities resulting from production, boron being an impurity with a concentration of less than 0.0005% and P+S≦0.015%, the chemical composition satisfying condition 410≦540�C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30.ltore- q.460.

The inventive steel has an essentially martensitic or lower bainitic structure comprising at least 90% martensite or lower bainite, at most 5% residual austenite, at most 5% ferrite.

The steel has a yield strength of between 480 MPa and 620 Mpa and a Charpy toughness V, KCV at -60� C. of more than 50 J.

Now, I have no idea what this al means exactly ;-)

You might find these intersting read.
http://gentleseas.blogspot.nl/2015/01/japan-offer-to-australia-soryu.html
http://gentleseas.blogspot.nl/2015/04/submarine-steel-strength-implications.html
http://www.dtic.mil/dtic/tr/fulltext/u2/616980.pdf

Appreciate the input and links thanks

 

[Penguin]

China will soon have Type 96 SSBN and since they will be having this beast than why can't they provide us Type 94 SSBN ? I think Pakistan is not willing to induct it because once SSBNs are spotted they are very vulnerable and those ballistic missiles equipped with nuclear warhead inside SSBNs would backfire and Chinese nuclear submarines are very noisy(expect the latest ones).

Type 096 is still under development, with first unit under way. Four type 094 are in service, four more are expected by 2020. So, that really is their current SSBN. It is not a matter that China can't provide, rather that it won't provide.

The problem with any SSBN or SSN is that you still need a base for them to operate from, that is safe. I'm not sure, given Pakistan's relatively short coastline and the range of e.g. India's Su-30MKIs that its a viable option. Apart from being VERY costly and manpower consuming.

 

[Nilgiri]

The problem with any SSBN or SSN is that you still need a base for them to operate from, that is safe. I'm not sure, given Pakistan's relatively short coastline and the range of e.g. India's Su-30MKIs that its a viable option. Apart from being VERY costly and manpower consuming.

What is the minimum number of SSBN's required to ensure that at least one is always out on patrol?

 

[Penguin]

What is the minimum number of SSBN's required to ensure that at least one is always out on patrol?

Five

 

[Tipu7]

Steel for the production of submarine hulls, which is characterized in that the chemical composition thereof comprises, by weight percent:

• 0.03%≦C<0.08%;
  
• 0.04%≦Si≦0.48%;
  
• 0.1%≦Mn≦1.4%;
  
• 2%≦Ni≦4%;
  
• Cr≦0.3%;
  
• 0.3%≦Mo+W/2+3(V+Nb/2+Ta/4)≦0.89%;
  
• Mo≧0.15%;
  
• V+Nb/2+Ta/4≦0.004%;
  
• Nb≦0.004%;
  
• Cu≦0.45%;
  
• Al≦0.1%;
  
• Ti≦0.04%;
  
• N≦0.03%;

• the remainder comprising iron and impurities resulting from production, boron being an impurity with a concentration of less than 0.0005% and P+S≦0.015%, the chemical composition satisfying condition 410≦540�C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30.ltore- q.460.

This is the ''elemental composition'' of Steel used in Making Submarine Hull.
In Making Hull of Submarine ''Alloy Steel'' is used as we want it to be non conductive, non corrosive, hard, ductile and durable at same time. Since Sub have to swim on surface of sea and dive deep in water so its frame have to endure different pressure at different levels. Moreover the maritime environment is highly corrosive in nature and composition of salt content vary from one ocean to another.
This is the reason the composition of steel for making hull vary from conventional submarine to AIP submarine & AIP submarine to Nuclear submarine.
Above mentioned Composition require very calculated manufacturing of steel. Usually it is done by using Electric Arc Furnace and in that furnace we use high grade wrought iron obtained from Blast Furnace. The presence of ''Boron & other impurities'' in final product indicate that these elements fail to convert into slag during Iron-Steel making process and this is often undesirable.
We have both Blast Furnace and Electric Arc furnace in Pakistan, so making steel for AIP diesel electric steel is not a big deal as there exist ''flexibility'' in percentage of content to be added, something which become more ''narrow'' in case of Nuclear submarine.

The inventive steel has an essentially martensitic or lower bainitic structure comprising at least 90% martensite or lower bainite, at most 5% residual austenite, at most 5% ferrite.

Its the ''Phase composition of steel''
After producing Steel it is subjected to Heat Treatment processes in order to attain required phase with desirable properties.

Consider Austenite as ''default'' phase which is present in every Steel before heat treatment. After it passes through various processes of Heat treatment it transform from one phase to another and give birth to phases like Pearlite, Banite, Carbide and Martensite. Small amount of Austenite remain untreated at the end even after getting final product. This Austenite is called ''Retained Austenite'' and its often not treated specifically, but it is unstable phase and changes its composition with time, particularly at sub zero temperature. (Nuclear submarine case) so while building Nuclear Submarine its necessary to get rid of this unstable phase. Hence this phase is also transformed into Martensite & Banite phases by a complex process of ''tempering'' which is pretty expensive and don't exist every where. Tempering process include heating and cooling of steel to specific temperature at rapid rate unless we gain required micro structure.

The largest content in Submarine composition Steel is Martensite, this phase is hard, tough but brittle. In Sub case it cannot be used as it will simply collapse under load due to brittleness. It is converted into ''Tempered Martensite'' which is ''flexible'' in strength and add ductility+hardness to material thus ensure safety of Submarine under varying pressure conditions.

The steel has a yield strength of between 480 MPa and 620 Mpa and a Charpy toughness V, KCV at -60� C. of more than 50 J.

Yield Strength is the ability of Material to restore its real shape by elastic restoration under the influence of load. If Yield Strength is high then it means it can absorb a lot of load / pressure with out undergoing plastic deformation in its shape. For Submarine its crucial for survival. 480 Mega Pascal is more than 4700 atm pressure. And it is very tough indeed.

And Charpy toughness is ability of material to absorb energy before fracture. KCV is its unit which in derivative of J/cm2 . As per above standard, hull must be able to bear 50 Joule of Pressure (load) per centimeter square of its area at -60 degree Celsius. Again, this is very strong and impressive.

 

[CHACHA"G"]

Hello All
Sir My take is.
Pakistan Navy Will have Total 13(minimum) SSK submarines ,,, 3 Agosta 90B , 4 Chinese ,,, and about 6 Western (Germany or Italy)
Then 4 diesel SSBs or ballistic missile submarines ( reports are we will have them or we are building them with help of china "the other 4 from the order of 8")
AND , In The End we will have 2 nuclear-powered submarines SSBNs .
If you look at recent development that will clearly pointing what I said , 8 Subs from China , as 4 SSKs and 4 SSBs , looking for western subs more likely Italian , minimum 6 again SSKs . And the plan of Building Nuclear Submarines ( Remember we have to build one ,).
Thank you All

 

[_NOBODY_]

If you look at recent development that will clearly pointing what I said , 8 Subs from China , as 4 SSKs and 4 SSBs , looking for western subs more likely Italian , minimum 6 again SSKs . And the plan of Building Nuclear Submarines ( Remember we have to build one ,).
Thank you All

All of these 8 submarines from China are S-20(with AIP).

 

[war&peace]

Why do we always need to import and do ToT. Pakistan spent billions of dollars on Agosta 90-B project for 4 submarines with ToT. Since SSBN is not our immediate concern, Pakistan should take initiative of developing SSBN indigenously using the experience gained over the years including the Agosta-programme, S-20 and so many frigates. I am not saying we should not get help from experienced countries and/or industries but initiative should be ours and we just get help from the best sources available to us for different systems and incorporate those in the development. And if SSBN is of immediate concern, then a few (one or two) can be leased from China to fill the gap. This will be much more fruitful and solid development with a lot of future potential. After all, we have to gain self reliance....then why not start now?

 

[Djinn]

All of these 8 submarines from China are S-20(with AIP).

Yes and most probably they will come with Chinese cruise missiles or perhaps Pakistan will go with Babur. Either way, the moment they arrive, Pakistan's TRIAD will be opertionalised.

 

[Arsalan]

Five

Wont it have something to do with the area it have to cover/patrol?