Why wasn't T-34 hull front upgraded?

[MikeyD]

Interesting point about the thick T34 hatch.

That hatch was cast instead on milled out of rolled steel, right? The Russians were well aware that cast was softer than rolled armor so a 75mm hatch may have been an attempt to equalize the softer hatch to the high hardness bow plate. Another example is the 'rounded edge' joining the upper and lower bow plates. I believe that was cast at over 100mm thick!

[rexford]

Originally posted by MikeyD:

Interesting point about the thick T34 hatch.

That hatch was cast instead on milled out of rolled steel, right? The Russians were well aware that cast was softer than rolled armor so a 75mm hatch may have been an attempt to equalize the softer hatch to the high hardness bow plate. Another example is the 'rounded edge' joining the upper and lower bow plates. I believe that was cast at over 100mm thick!

Analysis of that 100mm round casting between T34 nose and glacis showed it to be junk, full of bubbles and very poor resistance.

We speculate that the 75mm thick T34 driver hatch was high hardened to 440 Brinell like the rolled armor, and we think that 440 Brinell would resist the same whether rolled or cast.

[Mr. Tittles]

There is actually two different effects here. When an AP round pierces sloped armor, it changes direction. That is, its direction of motion and orientation are changed.

In other cases, an AP round may strike a thinner object and its direction of motion is not changed but its orientation will change. In other words, it has pitched its nose so that it is not axially lined up with the forward motion. This would have an effect on its ability to penetrate armor since the sharp nose is not striking armor at a favorabe angle.

Another effect is the rapid loss of spin. When a spinning object like a AP rifle projectile pierces armor, it must 'stall' out the spin quickly. This results in a force on the projectile.

[rexford]

When a track link is added to highly sloped armor, the links may result in decreased ricochet forces and therefore aid in penetrating the armor. This is what the German tests suggest.

Maybe the links act like shot traps.

It would seem that there is not enough time or distance to really rotate the round through the track link, so helping to keep the round more horizontal may be a possible explanation for the German tests with track pieces at various angles.