soviet armor steel database

[Alejandro_]

There is no reason to continue any conversation with You if You are not comprehending what is actually discussed here...

It seems that your modus operandi is to repeat your theories and when asked for sources start complaining about others' lack of understanding. For example:

However, the T44, which in itselfe was a post ww2 tank which happened to be conceived and partially tested during ww2, was specified to resist domestic AP, and at one point had the requirements to include also german AP resistence.

I corrected you on the T-44 being a post war tank. However, I have asked several times the source which state that the T-44 was only tested with Soviet AP armour and then requirements for German AP armour included. I gave you the information with the original requirements and several sources.

So, for the third time. What is the source?

I referred actually to RHA armor in regard to the sensible specs which related thickness to hardness, not to cast Armor. 42SM WAS NEVER CAST ARMOR, what´s so different for You to understand here?

I don't recall saying that 42SM was cast. In any case, I just want you to explain this:

Obyekt 701 (IS-4) used 42SM armour in the hull and 66L (cast) in the turret. The first prototype was completed in April 1944. Can you provide details on the space-time machine created by the USSR that explained:

All the critical research was conducted in the 1950-1954 timeframe. The latter 42-SM development closely mirrors german RHA R&D, though the germans arrived at these concluisons already during their R&D in the early 30´s, not in the late 40´s/ or even early 50´s as did the soviets.

[Peasant]

I don't know if you've already seen this table, but for the sake of other people researching this I'll post it here:



From the document about ballistic testing of captured german AT guns against domestic armour: viewtopic.php?f=47&t=216079

[critical mass]

There is a considerable variance in the analysis reported for medium hard no.5&8 and high hardness no.2&7 in the table above.
All the except one medium hardness RHA imprint depths indicate hardness above the 1st ductile /brittle transition point.
This implies a tad bit too hard KV1 armor (FD6633), but acceptably so, if increased resistence at low obliquity is required.

[Peasant]

Not armour steel, but I've just found some info:

"Бронебойные тупоголовые снаряды с баллистическим наконечником калибра 76 и 85 мм изготавливались из стали 35ХГСА. Тупоголовые 122-мм снаряды с баллистическим наконечником выполнялись из стали ХНЗМ."

Translation:

"Blunt headed APBC-HE projectiles of calibers 76 and 85mm were made from mark of steel 35HGSA. Blunt headed APBC-HE projectiles of caliber 122mm from HNZM"

Link: https://mybiblioteka.su/4-88447.html

[critical mass]

стал 35ХГСА:
http://metallicheckiy-portal.ru/marki_m ... stk/35XGSA
a medium carbon, chrome-silicon-manganese type steel, suitable for small section thicknesses.
Hardenability is present, though would have been better had they used higher carbon.

стал (30)ХНЗМ:
slightly less carbon, slightly more alloys to adress the larger section thickness. Hardenability is impaired by low carbon content.

noteworthy metallurgical informations to different steels and their physical properties are to be found in B.B. Guljaev´s book (Литейные процессы).

I found notice in it about 42-S medium hardness and 43PS- low hardness armor beeing introduced in the IS-program (53-S for thicknesses larger than 100mm and the cast tower (?and hull?) elements beeing initially 70-L, then 71-L high hardness, followed by 66-L for small elements and 74-L for heavy ones post war). 42S and 43PS improved 1944 by adding small amounts of molybdenium (I suppose in order to reduce temper brittleness in production armor, becoming 42-SM, 43-PSM, not known if production tanks received that, since 42S was manufactured until 1947). Later further improved by reducing hardness specification for 42-SM. Later improved by differential hardening and improved heat treatment depending on thickness. In this particular regard, the following quote demonstrates that the foreign advances in this regard were closely studied:

Термическая обработка — сложный процесс, за­висящий от назначения брони, ее толщины и хими­ческого состава, обычно включает закалку с после­дующим отпуском. Закалкой достигается необходимая твердость брони, а отпуском — требуемая вязкость. Внимательно изучается опыт зарубежного танко­строения.

By 1969 finally, electroslag resmelting was experimentally carried out in connection with 42-SM, which increased the impact strangth and lowered to brittle transition temperature from -20°C to -40°C.

I find it fairly difficult to obtain even chemical analysis for 42S and 43 PS steels, a heat treatment diagram is elusive, too..

[Peasant]

"Both the upper and lower glacis plates and the side hull plates are constructed from 42 SM armour grade steel. The rear armour plate and the roof plate was made from 49 S armour grade steel, and the belly of the tank was made from 43 PSM armour grade steel. The cast steel turret was made from 74L CrNiMo armour grade steel, while the two-piece roof welded onto the cast turret was made from 43 PSM steel. The 49 S and 43 PSM steel plates installed in the roof and belly of the tank was quite thin - only 20mm, so it is quite surprising that these steels are rather soft for their thickness. This table states that 49 S and 43 PSM have a hardness of only 180-250 BHN. The rule of thumb is that thinner plates are easier to harden than thicker plates, so the plates used in the tank are definitely closer to latter than the former, but even so, that is relatively soft for such thin plates. 42 SM and 74L, on the other hand, are medium hardness steels with a hardness of 270-340 BHN and still quite thick. The hardnesses are optimal for resisting armour piercing rounds for the thicknesses of the given plates. This information comes from the "Техника и Вооружение" magazine."

More: https://thesovietarmourblog.blogspot.co ... /t-54.html

[critical mass]

This has been discussed above. 42SM grade steel was medium hard RHA, optimized depending on thickness and application. It´s more thickness graded hardness and generally much better tempered than it´s ww2 vintage 42S precursor was.
43PSM was a soft, shock resistent material, optimized as mine protective bottom plate. 73L and 74L were also softer cast armors, replacing the 70L and 71L high hardness cast materials used abundantly during ww2 for IS-series and T34/85 series production.
There is a general trend at first, to reduce hardness after ww2 in both, RHA and cast armor grades. Ultimately, 42SM and 74L arrived at exactly the same hardness levels as german ww2 armor steels, while 43 PSM was somehow softer than german mine protective bottoms.
Later, the hardness of 42SM increased again, but this was made possible by use of more sophisticated alloying and heat treatment practices (electroslag resmelted steel, f.e.).

[seppw]

Do you really think they did not extract any technology from more developed nations during this period?

Sure, and they waited until 1950-54 to apply it. Perhaps you have some documentation about this steel technology extraction?

Sächsische Gußstahlwerke(Döhlen) were almost completely dismantled between 46 and 48. The Soviets were keen on obtaining the heating and quenching equipment.

StA-D Rep 11384 #4422

[Stiltzkin]

More info, RGAE material and Там же, Оп, 7. Д.22, Л.10; Д.51. ЛЛ.2,5, on 71L grade steel.

[critical mass]

Thanks Sitzklin. That’s helpful. The T34/85 introduced 71L high hardness armor, for cast elements. Notice the massive increase in Nickel as a primary toughening agent and a slight reduction of Manganese again, supporting toughenability -at expense of some hardenability). The same tank also employed RHA in Form of soft 2P (f.e. armored bottom) and high hardness 8S (RHA hull armor).
2P, treated to relatively soft hardnesses, had reduced hardenability (primarily by a lack of chromium) and somewhat also reduced toughening (lack of nickel). This was necessary because 2P would need to be tempered. Presence of Ni and Cr combinations does increase the suspectability of suffering from unintended temper brittleness (called Krupp disease sometimes due to Krupp naval armor in the 1890s was suspect to temper brittleness, if the cooling times were not carefully controlled).

The T34/76 still used 8s for cast elements, for which this type of armor is unsuited due to its tendency to easily form brittle carbide networks in larger section thicknesses.

[Peasant]

Doesn't seem like this was posted here before: https://t34inform.ru/doc/sp_Armor_NKSP-1940.html

[Peasant]

Was this table posted here before?