The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice.
This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment easily.
Various kinds of "active armor" trigger the munition by a thinner layer of metal well ahead of the real thick armor plate, then produce counter-explosions to break the jet.
It’s not molten, and heat plays no role in the penetration ability. This is a very common misconception.
It’s simply focused kinetic energy that does it. The cone focuses the copper into a slug like object, and the slug becomes similar to an extremely powerful bullet.
So it's like that old picture of the grass straw driven through the telephone pole by nothing but hurricane wind?
The flimsy straw could do it simply because of how fast it was moving. The strength of the straw doesn't matter, simply it's mass, moving that fast, carries itself through, ie the leading edge is not being pushed from behind like a nail, more like a bullet with a string attached?
Setting aside the simplification, that probably the mass of the rest of the straw does play some part not absolutely zero, is that a reasonable way to conceptualize it?
Are you certain that a hurricane can blow a straw through a telephone pole? I hadn't heard of this phenomenon and was interested. I was unable to find a good source.
According to this article, the National Oceanic and Atmospheric Association thinks it's not possible:
The picture (perhaps multiple but at least one) was a piece of hay poked right through a telephone pole, in the aftermath of some kind of storm. Not a tree. It was shown in grade school in the 80s or late 70s.
It’s really hard to get a slug
Moving like that without tearing it apart. It’s easier to use the explosive to spread the force over a wider area initially but in a way that the projectile is formed by the concentration of the explosive forces mashing it all together. Weird.
It's not actually liquid, it only behaves like one on impact due to the magnitude of the forces. It's more accurate to say it erodes through the armor instead of melting.
Waterjet cutting uses water to propel a powder which acts as an abrasive, like an infinite stream of sandpaper. I don't think water by itself will achieve much.
Waterjeting without abrasive is a thing, it's used for soft materials like rubber... and there are some companies marking higher pressure approaches for metal (though usually with tiny amounts of abrasive rather than none at all).
Sounds like pressure washing vs sand blasting. Only difference between the two (aside from drastically different effect) is sand blasting has an intake tube to suck sand into the water jet.
Water is not doing the cutting there. Water is just the carrier for garnet abrasive, which does the actual cutting. Garnet is roughly three times harder than steel, so at high pressure cuts it very effectively.
As far as I know, it could be little qanons in there stealing the steel atoms to build jfk jr's moon rocket. However, the principle physicist for the nuclear emergency search team described it using the butter analogy.
The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice.
This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment easily.
Various kinds of "active armor" trigger the munition by a thinner layer of metal well ahead of the real thick armor plate, then produce counter-explosions to break the jet.