US Military News, Reports, Data, etc.


Suetham

Senior Member
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One wonders how common this is in the American MIC.
This led me to question the reason for testing at this temperature. What catches is the impact energy variation, as seen in the attached figure. The figure in question is already an evaluation of the HY-80 steel that is used in the American subs of the Los Angeles class, with the exception of Seawolf and Virginia, which uses HY-100 steel.

In this test in question, the decrease in impact energy from a temperature of -60°C and -80°C is more significant than between -20° and -60°C, this demonstrates the decrease in impact strength of the steel when the test temperature decreases, as in news states that there was no compromise of the hull, suggests that even the test in question is not performed at the temperature requested by the USN, the steel is within the acceptable standard, with either HY-80 and/or HY-100 being used by the USN in the subs and that the company in question provides.

The tests that are carried out on HY-100 steel offer exceptionally higher impact strength than HY-80, so I think the actual test parameters of HY-80 and HY-100 steel are exceptionally different within that line. of -73.3°C that the news reports, I remotely believe that it is in fact the HY-80 steel that the Los Angeles grade uses, the period they are reporting from 1985 to 2017 also means that the HY-100 steel was falsely presented to USN standards, a news report last year describing the case mentions that HY-100 steel was also counterfeited in tests, and that the accused woman hinted that she performed the tests at temperatures lower than -73.3°C, for example. , if the tests were performed at the temperature -60ºC, there is a large variation between the impact energy, the attached figure exemplifies this issue.

Although the news claims that there was no structural compromise of the subs, the news confirms that at the time of these tests not being carried out as requested by the USN, the steel resistance parameters of these subs to the impact were not tested, this may imply the fact that the USN may not be aware of the actual operating conditions of each of these subs that were tested and the data manipulated, because the USN's required parameter testing of impact strength has not been tested to withstand the massive pressure changes.

Now, why such a test is 73.3°C? I have no idea. Perhaps someone with that information can grace us.
 

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Maikeru

Senior Member
Registered Member
This led me to question the reason for testing at this temperature. What catches is the impact energy variation, as seen in the attached figure. The figure in question is already an evaluation of the HY-80 steel that is used in the American subs of the Los Angeles class, with the exception of Seawolf and Virginia, which uses HY-100 steel.

In this test in question, the decrease in impact energy from a temperature of -60°C and -80°C is more significant than between -20° and -60°C, this demonstrates the decrease in impact strength of the steel when the test temperature decreases, as in news states that there was no compromise of the hull, suggests that even the test in question is not performed at the temperature requested by the USN, the steel is within the acceptable standard, with either HY-80 and/or HY-100 being used by the USN in the subs and that the company in question provides.

The tests that are carried out on HY-100 steel offer exceptionally higher impact strength than HY-80, so I think the actual test parameters of HY-80 and HY-100 steel are exceptionally different within that line. of -73.3°C that the news reports, I remotely believe that it is in fact the HY-80 steel that the Los Angeles grade uses, the period they are reporting from 1985 to 2017 also means that the HY-100 steel was falsely presented to USN standards, a news report last year describing the case mentions that HY-100 steel was also counterfeited in tests, and that the accused woman hinted that she performed the tests at temperatures lower than -73.3°C, for example. , if the tests were performed at the temperature -60ºC, there is a large variation between the impact energy, the attached figure exemplifies this issue.

Although the news claims that there was no structural compromise of the subs, the news confirms that at the time of these tests not being carried out as requested by the USN, the steel resistance parameters of these subs to the impact were not tested, this may imply the fact that the USN may not be aware of the actual operating conditions of each of these subs that were tested and the data manipulated, because the USN's required parameter testing of impact strength has not been tested to withstand the massive pressure changes.

Now, why such a test is 73.3°C? I have no idea. Perhaps someone with that information can grace us.
Perhaps the very low temperatures are what the subs might be exposed to if operating under the Arctic ice cap?
 

montyp165

Junior Member
My thinking is that the specified testing temperature is intended to approximate the combined pressure and temperature operating limits that the steel is expected to possibly encounter in terms of energy state resistance, as although the ocean of course never gets that cold a submarine's operating environment acts as continuous stress on steel, so being able to resist cold temperature compression (and potential impacts such as surfacing under ice) with a greater margin than the expected operating depth is significant.
 

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