09V/09VI (095/096) Nuclear Submarine Thread

[weig2000]

I strongly doubt that the reason for China not proceeding to produce 095/096 is due to problems with high-end CNCs. It's even more ludicrous to suggest that reason is that China has to source core components for CNCs from Germany or Japan. It all sounds like a fantasy story inspired by the alleged Toshiba CNCs helping Soviet Union achieve its magic leap of progress in submarine quietness.

There might be any number of reasons for the supposedly delayed production of 095/096, but lack of proper CNCs would be ranked among the least likely.

 

[antiterror13]

I don't think there is any confirmation. I'm just assuming they are single or hybrid. Regarding the 12m segment we saw, my submarine contact believes that it is for 096. He did say that it is in the "graving dock", so may be a trial production rather than a boat under construction. That is quite interesting, because I thought it would be a while before they would even try something like trial production for 096. If they have started 096 project at this point, then 095 should be further along and already in production for some time. Keep in mind that Ohio clas has beam of about 12.5 m for reactor hull IIRC. So 12m would be a reasonably wide hull for 096.

At this point, I've also been told that the best CNC machine that China has access to is still likely some years behind the best one available for America. The really high end CNCs are still off limit to Chinese companies. So it is likely that while China has made a lot of progress up until this point, they are still a good decade or two behind America in machineries (like they are in turbofan engine). But even with that, 095 will likely be wider than Virginia class, so the first 095 boat is likely to be around early Virginia class in noise level and then steadily improving as they work out the problems.

As for why they've waited until this long to mass produce 093B and then 095, I think the answer is quite simple. They've only figured out how to produce competitive CNC machines (that are mostly using domestic parts) in the past 4 or 5 years. You really can't start detailed designs of a new submarine class until you are able to produce steam turbine with very high precision manufacturing.

The 095 class and mass production of 095/093B is quite significant. It will final give China a matching modern nuclear submarine fleet to USN. At a time when USN is facing a retirement cliff of LA/Ohio class subs and having trouble ramping up Virginia class production due to not having enough welders. If Bohai shipbuilding can ramp up production to something like 6 to 8 a year, that will be very significant. Eventually, I think PLAN will have a much large nuclear submarine fleet than USN. Based on the size Huludao facilities, I think that might come sooner than what most of us expected.

Thanks. Quite interesting if the bottleneck is in super high end CNC machine. Surely China has much more advanced CNC machines than the Russian, the question is how come with much less advanced CNC machines, the Russia could manage building so advanced big nuclear subs ?

 

[FairAndUnbiased]

Thanks. Quite interesting if the bottleneck is in super high end CNC machine. Surely China has much more advanced CNC machines than the Russian, the question is how come with much less advanced CNC machines, the Russia could manage building so advanced big nuclear subs ?

because CNC is not the limiting factor. if you are machining at ~10 um tolerance like the parts listed above for a gigantic turbine, the temperature gradient and even the pressure drop from hot side of the turbine to the cold side of the turbine is enough to cause difficult to predict mechanical deformations far bigger than the machining tolerance.

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even a small steam turbine the typical steam turbine is ~800 mm (30 inches) yet is made up of very thin blades. even a 1 psi pressure differential is 700 lbs force/3 kN force on blades of thickness in ~mm.

 

[antiterror13]

because CNC is not the limiting factor. if you are machining at ~10 um tolerance like the parts listed above for a gigantic turbine, the temperature gradient and even the pressure drop from hot side of the turbine to the cold side of the turbine is enough to cause difficult to predict mechanical deformations far bigger than the machining tolerance.

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even a small steam turbine the typical steam turbine is ~800 mm (30 inches) yet is made up of very thin blades. even a 1 psi pressure differential is 700 lbs force/3 kN force on blades of thickness in ~mm.

Thanks and I don't understand what is your point/s ? did you try to answer my post or explaining something else ?

 

[FairAndUnbiased]

Thanks and I don't understand what is your point/s ? did you try to answer my post or explaining something else ?

The point is that the um level tolerances that super high end CMC machines are likely not required.

 

[antiterror13]

The point is that the um level tolerances that super high end CMC machines are likely not required.

Thanks, thats what I thought too as Russia seems fine with outdated CNC relatively to China

So, basically you don't agree with what @tphuang said in regard to super high end CNC ?

 

[tphuang]

Thanks. Quite interesting if the bottleneck is in super high end CNC machine. Surely China has much more advanced CNC machines than the Russian, the question is how come with much less advanced CNC machines, the Russia could manage building so advanced big nuclear subs ?

Which Russian sub is that advanced? The Russian boomers get tracked as soon as they leave the port by USN. Akula class became quiet in the later units because they are just so large, so that Russians could put more sound absorbers in there. Yasen class is said to be close to Virginia class because they have even wider pressure hull than Akula class. I don't think the Russians are actually better at making quieter steam engines and different pumps than China. China may be able to improve their rafting technology from cooperating with the Russians, but I don't see any reason why Russian sound absorbers would be better than what China has now.

I don't claim to be an expert in how to make these things really quiet. I'm simply relaying what I heard about precision manufacturing from submariners. From what I can see, the final design for 093B and 095 lines up almost perfectly with when China got competent at precision manufacturing. It passes the smell test for me. Of course there are other things involved in reducing noise level. There is probably a lot of research into materials used in manufacturing and material used in rafting and tiling and such. I'm novice in all of these areas. It just seems to me that submarine quieting technology is a manifestation of the overall hard science/tech development. And China has only become good in this area very recently.

 

[FairAndUnbiased]

Which Russian sub is that advanced? The Russian boomers get tracked as soon as they leave the port by USN. Akula class became quiet in the later units because they are just so large, so that Russians could put more sound absorbers in there. Yasen class is said to be close to Virginia class because they have even wider pressure hull than Akula class. I don't think the Russians are actually better at making quieter steam engines and different pumps than China. China may be able to improve their rafting technology from cooperating with the Russians, but I don't see any reason why Russian sound absorbers would be better than what China has now.

I don't claim to be an expert in how to make these things really quiet. I'm simply relaying what I heard about precision manufacturing from submariners. From what I can see, the final design for 093B and 095 lines up almost perfectly with when China got competent at precision manufacturing. It passes the smell test for me. Of course there are other things involved in reducing noise level. There is probably a lot of research into materials used in manufacturing and material used in rafting and tiling and such. I'm novice in all of these areas. It just seems to me that submarine quieting technology is a manifestation of the overall hard science/tech development. And China has only become good in this area very recently.

Delta 3/4 is about the size of 094 with 8.7 m diameter pressure hull and a hump back to accommodate the missiles.

The big problem is not that quieting machinery is particularly hard but that quieting isn't really relevant in any other industrial application. Nobody cares how loud a steam turbine in a powerplant is.

 

[supercat]

Are super advanced CNC required for aviation engines? It seems that China has made some progress on WS-10, WS-20, and some other aviation engines.

 

[FairAndUnbiased]

Are super advanced CNC required for aviation engines? China seems to have made some progress on WS-10, WS-20, and some other aviation engines.

Turbine blades are cast, not machined... Even cooled machining can cause cold work stress in single crystal blades, introduce a dislocation, and make it no longer single crystal. That would increase vulnerability to creep.

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