Friday, 10 May 2013

Soviet Armour Quality

I've been focusing on German armour a lot, so it's only fair that I look at the quality of Soviet tank armour for a little bit. As we've seen, German armour quality post 1942 is quite brittle, with lots of spalling, cracking, and fragmentation going on. Let's see what Soviet armour is like in that regard.

CAMD RF 38-11355-785

In the NII-48 report "Penetrations of T-34s and reasons for their losses", a large number of knocked out T-34s were examined, for, as you may have guessed it, reasons why they no longer work. As well as offering a very interesting breakdown of calibers and impact locations, it also offers an analysis of armour quality. Let's take a look.

"6. Comments on the quality of armour on the T-34.

Existing data on impacts allows us to conduct an analysis of the armour used on the T-34. Table #25 shows information on the type of impact, and the caliber responsible for the impacts, in percentages."

The first line is "safe impacts", or non-penetrating hits. 54.1% of hits do not penetrate the T-34, this is pretty good. The rest of the line breaks it down by caliber: 3.2% by 20 mm shells, 6.8% by 37 mm shells, 4.9% by 42 mm shells, 30.6% by 50 mm shells, 3.2% by 75 mm shells, 0.2% by 88 mm shells, 2% by 105 mm shells, and 3.2% from indeterminate sources.

The next section is the one we can judge armour quality by. 42.0% of the impacts were clean penetrating hits. Only 2.1% of the hits were ragged (indicating impurity in the steel), 0.6% had cracks, 0.6% led to spalling, and 0.6% had fragments fall off. This is pretty good! The analysis agrees.

"It can be seen from the table that the percentage of brittle impacts (ragged penetrations, cracks, spalling, fragementation) is very small, 3.9%. Most of the brittle impacts are from artillery calibers greater than 50 mm, and from unknown sources, which could be bombs, grenades, mines, etc. Overall, the quality of armour is satisfactory. Judging the armour's resistance is not possible, since the ranges and angles of impact are not known."

NII-48 explores the topic in that last sentence in a different paper, and it will be the topic of another article.

6 comments:

  1. Good article, Peter, but I would like to know when was the document printed.

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  2. The report was prepared in September/October of 1942.

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  3. I think the overall ratio of clean penetration is 42.0, not 42.9. The number doesn't add up.

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  4. What's the difference between ragged/spalling/fragmentation exactly?

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    1. A ragged penetration is much larger than a caliber in size. A spalling it is when armour is not penetrated, but fragments of the armour fly off the other side and damage the crew and components. That last one is when the armour plates crack and fall off as a result of being hit. All are indicative of over-hardened or poor quality armour.

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