Military Review

Tank armor industry. Pre-war Soviet achievements

55

Source: t34inform.ru


Waiting for the war


Problems with tank production in the Soviet Union in the 20-30s, associated primarily with the unavailability of the industry, was partly explained by the lagging of the armored industry. By the beginning of 1932, only two of the planned four enterprises could melt and roll armor. These were the Izhora and Mariupol factories. Due to the excessively high requirements for the speed of production (this was a sign of that time), these plants were chronically behind plans. So, at one of the oldest enterprises in the country, the Izhora plant in the city of Kolpino, in a year they were able to master only 38% of the plan, and in Mariupol at the Ilyich plant - only one quarter. This was largely due to the production of complex cemented heterogeneous armor, which they knew how to make in our country since 1910. This type of armor was required to withstand sharp-headed projectiles and bullets, which the usual homogeneous medium and low hardness did not provide. At that time, cemented armor was divided into two grades: low-tempered unilaterally cemented with a sufficient hard back side and in the second version - with a medium hard back side. Basically, for the production of such "sandwiches" required chromium-molybdenum and chromium-nickel-molybdenum steel, which required scarce imported ferroalloy additives. The main alloying element of these steels was chromium (1,5–2,5%), which promotes intensive carburization and the achievement of high hardness of the cemented layer after quenching. An attempt to use domestic manganese and silicon for case-hardened steel instead of imported chromium yielded a negative result. When alloyed with manganese, it was revealed that the steel is prone to grain growth at the carburizing temperature (920–950 degrees Celsius), especially with long exposures required for carburizing to a great depth. Correction of the carburized layer overheated during cementation presented significant difficulties and was associated with the need to apply multiple recrystallization, which caused significant decarburization of the cemented layer and sheet leads, and was also economically unprofitable. However, until the early 30s, cemented armor found use in both aviation, and in tank building. In aircraft, armor plates up to 13 mm thick were cemented, like tank armor up to 30 mm. There were also developments of bullet-resistant 20-mm cemented armor, which did not go beyond experimental development. Such armor was unambiguously supposed to be massive, which required just gigantic resources for the development of production.


Smelting of armor for the T-34 during wartime at the factory # 183. Source: t34inform.ru

Despite such difficulties with the production of cemented armor, the hull of the T-28 tank was almost completely made of it. But gradually the domestic industry abandoned the technologies for cementing armor plates, largely due to the extremely high rejects. Considering the production plans demanded by the government and specialized people's commissariats, this was not at all surprising. The Izhora plant was the first to switch to the new armor, having mastered the smelting of high-hard chromium-silicon-manganese armor "PI". In Mariupol, they mastered the heterogeneous manganese "MI". The country gradually switched to its own experience in designing armor. Until that time, it was based on foreign technologies (mainly British). The refusal to cement the armor made the sheets thicker with the same armor resistance. So, instead of 10- and 13-mm cemented armor, the T-26 hull had to be welded from 15-mm sheets of Izhora steel "PI". In this case, the tank was 800 kilograms heavy. It should be noted that the transition from expensive cemented steel to relatively low-cost homogeneous armor technology turned out to be very useful in wartime. If this had not happened in the pre-war years, the development of smelting and rolling of expensive types of armor would be unlikely, given the evacuation of enterprises in 1941-1942.

Since the pre-war years, the main role in the search and research of new types of armor has been played by the "Armor Institute" TsNII-48, which is now known as the NRC "Kurchatov Institute" - TsNII KM "Prometheus". The TsNII-48 team of engineers and scientists determined the main directions of the domestic armor industry. In the last decade before the war, the appearance abroad of armor-piercing artillery in calibers from 20 to 50 mm was a serious challenge. This forced the developers to look for new recipes for cooking tank armor.

Birth of 8C


Cemented armor resistant to sharp-headed shells and bullets on light and medium armored vehicles can only be replaced with high-hardness steel. And this was successfully mastered by domestic metallurgists. Hulls of armored vehicles BA-8, light tanks T-10 (armor thickness 10 mm, frontal - 60 mm), T-15 (armor thickness 35 mm) and, of course, medium tanks T- 26 (armor thickness 15 mm). The Germans also had high-hardness armor a priority. In fact, all armor (starting with infantry helmets and ending with aviation protective structures) over time became of high hardness, replacing the cemented one. Perhaps only heavy KVs could afford medium-hardness armor, but this had to be paid for with greater sheet thickness and the final mass of the tank.

The 8C armor steel, the basis of the anti-cannon defense of the T-34 tank, became a real crown of creativity of domestic metallurgists. It should be noted that the production of 8C armor in the pre-war years and during the Great Patriotic War was two seriously different processes. Even for the pre-war industry of the Soviet Union, the production of 8C was a complex and expensive process. They could successfully master it only in Mariupol. The chemical composition of 8C: C - 0,22-0,28%, Mn - 1,0-1,5%, Si - 1,1-1,6%, Cr - 0,7-1,0%, Ni - 1,0-1,5%, Mo - 0,15-0,25%, P - less than 0,035% and S - less than 0,03%. For smelting, open-hearth furnaces with a capacity of up to 180 tons were required, pouring future armor into relatively small molds of 7,4 tons each. The deoxidation of the liquid alloy (removal of excess oxygen) in the furnace was carried out in a costly diffuse method using carbon or silicon. The finished ingot was removed from the mold and rolled, followed by slow cooling. In the future, the future armor was again heated to 650-680 degrees and cooled in air: it was a high vacation, designed to give steel plasticity and reduce fragility. Only then could the steel sheets be machined, since the subsequent hardening and low tempering at 250 degrees made it too hard. In fact, after the final hardening procedure with 8C, it was difficult to do anything other than weld the body out of it. But here, too, there were fundamental difficulties. Significant internal welding stresses arising from the low ductility of the metal of the 8C armor, especially with its low quality, leading to the formation of cracks, which often increased over time. Cracks around the seams could form even 100 days after the tank was manufactured. This became a real scourge of the tank building of the Soviet Union during the war. And in the pre-war period, the most effective way to prevent the formation of cracks during welding of 8C armor was the use of preliminary local heating of the welding zone to a temperature of 250-280 degrees. For this purpose, TsNII-48 developed special inductors.

Tank armor industry. Pre-war Soviet achievements
"Plant named after Ilyich. Steel casting". By N.K. Bendrik, 1937. Source: pinterest.com



Source: t34inform.ru

8C was not the only steel grade for the T-34 armor. Where there was an opportunity, it was changed to other, cheaper varieties. In the pre-war period, TsNII-48 developed the 2P structural armor, the production of which significantly saved energy and simplified sheet rolling. Chemical composition of 2P: C - 0,23-0,29%, Mn - 1,2-1,6%, Si - 1,2-1,6%, Cr - less than 0,3%, Ni - less than 0,5, 0,15%, Mo - 0,25-0,035%, P - less than 0,03% and S - less than 2%. As you can see, the main savings were in scarce nickel and chromium. At the same time, very tight tolerances for the presence of phosphorus and sulfur remained unchanged for 2P, which, of course, was difficult to achieve, especially in wartime. Despite all the simplifications, structural armor made of 48P steel was nevertheless subjected to heat treatment - quenching and high tempering, which significantly loaded the thermal equipment necessary for the heat treatment of more critical armor parts of tanks, and also significantly increased the production cycle. During the war, TsNII-8 specialists were able to develop technologies for obtaining similar steels, the production of which freed up resources for the XNUMXC main armor.

To be continued ...
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  1. Same lech
    Same lech 15 October 2020 05: 31
    +8
    Thanks Eugene for the article hi very interesting ... I had a chance to work as a thermist ... very hard work ... not everyone can do it .... so I can imagine everything that you described.
    I look forward to continuing.
    1. garri-lin
      garri-lin 15 October 2020 19: 37
      0
      Since you are in the subject, please explain. The high vacation mentioned in the article is an annealing in modern slang?
      1. D-Master
        D-Master 17 October 2020 10: 26
        +2
        No. Annealing and tempering are different processes
        Annealing is a heat treatment operation consisting in heating the steel, holding it at a given temperature and then slowly cooling together with the oven[i] [/ i]. As a result of annealing, a stable structure is formed, free from residual stresses.
        Vacation - This is a technological process, the essence of which is the heat treatment of a metal or alloy hardened to martensite, the main processes in which are the decomposition of martensite, recrystallization and polygonization. It is carried out in order to relieve internal stresses, to give the material the necessary operational and mechanical properties. It is carried out by heating to a temperature below the critical one and subsequent cooling in vacuum or air. When high Tempering steel receives the best combination of mechanical properties, increasing strength, ductility and toughness, therefore, high tempering of steel after hardening it to martensite is prescribed for forging dies, springs, springs and parts subject to high stresses (for example, car axles, engine connecting rods).
        1. garri-lin
          garri-lin 17 October 2020 12: 45
          0
          It turns out the difference in heating temperature and cooling conditions. Thanks a lot.
  2. Kote Pan Kokhanka
    Kote Pan Kokhanka 15 October 2020 05: 50
    18
    I never thought it would be interesting to read about armor!
    Thank you very much, Eugene!
    Good day to everyone, Kote!
    1. Mordvin 3
      Mordvin 3 15 October 2020 06: 01
      10
      Quote: Kote pane Kohanka
      I never thought it would be interesting to read about armor!

      It's magic. It happened to be in the foundry, a fascinating sight when the molten metal flows.
    2. Mordvin 3
      Mordvin 3 15 October 2020 06: 11
      +5
      Quote: Kote pane Kohanka
      I never thought it would be interesting to read about armor!

      And I also read memoirs, I don’t remember who, their armor didn’t work, they called the master grandfather, he began to mumble prayers and throw candles. Like - it won't work without God's help ...
      1. phair
        phair Yesterday, 10: 44
        0
        Normal when the clock is gone. Read a prayer and like a chronometer;)
    3. Rurikovich
      Rurikovich 15 October 2020 06: 37
      +6
      Quote: Kote pane Kohanka
      I never thought it would be interesting to read about armor!

      The same feeling what yes hi
  3. The leader of the Redskins
    The leader of the Redskins 15 October 2020 06: 56
    +5
    Thank you, author, for the interesting material. Very interesting to read. Once upon a time, a book marked with the Stalin Prize fell into the hands, it seems, "Steel has boiled." It also described the difficulties of metallurgists in the production of armor after evacuation.
    1. Blacksmith 55
      Blacksmith 55 15 October 2020 09: 57
      +6
      Good morning .
      Perhaps there is a book called "Steel Boiled", but I think you are mistaken.
      "How Steel Boiled" and "Steel and Slag" are two books that I read in my youth. Describes the production of steel before the war, if I am not mistaken, in the Donbass, and during the occupation.
      Thank you for reminding me, I should read it again.
      1. The leader of the Redskins
        The leader of the Redskins 15 October 2020 10: 03
        +3
        It may very well be. I read it for a long time, as a child. Thanks for the amendment.
        1. Blacksmith 55
          Blacksmith 55 15 October 2020 10: 07
          +7
          Do not mention it .
          For me, a book is much better than any film.
          Yesterday I asked myself what to read? You helped.
  4. Undecim
    Undecim 15 October 2020 07: 12
    18
    The main alloying element of these steels was chromium (1,5–2,5%), which promotes intensive carburization and the achievement of high hardness of the cemented layer after quenching.
    Chromium does not affect carburization in any way. Chromium is a carbide-forming alloying element. At a low Cr / C ratio of chromium content in relation to iron, only cementite of the (Fe, Cr) 3C type is formed. With an increase in the ratio of the chromium to carbon content in the Cr / C steel, chromium carbides of the type (Cr, Fe) 7C3 or (Cr, Fe) 23C6 or both appear. Chromium increases the heat-hardening capacity of steels.
  5. Mavrikiy
    Mavrikiy 15 October 2020 08: 15
    +3
    Mariupol, good. Come on Magnitogorsk!
  6. Mountain shooter
    Mountain shooter 15 October 2020 08: 56
    +4
    Yes, the more you learn, the more you understand that war is not only a battlefield. It is also being conducted in the deep rear. The one who will saturate the troops with good weapons faster and cheaper (not the best is always expensive) and GOOD ENOUGH - will give his troops an advantage, and the enemy - a headache, loss of initiative and, as a result, defeat.
  7. BAI
    BAI 15 October 2020 09: 08
    +4
    TsNII-48, which is now known as NRC "Kurchatov Institute" - TsNII KM "Prometheus".

    TsNII KM "Prometey" and NRC "Kurchatov Institute" are not the same thing. Since 2016, the independent Central Research Institute is part of the SIC. SIC acts as a kind of holding. Here it is more appropriate to recall that TsNII-48 has an heir - the Research Institute of Steel, which is actively involved in armor issues in our time.
  8. Undecim
    Undecim 15 October 2020 09: 53
    16
    So, instead of 10- and 13-mm cemented armor, the T-26 hull had to be welded from 15-mm sheets of Izhora steel "PI".
    Here the author missed a very important stage.
    In 1932-1933, the production of tanks began to move from riveted and bolted joints of hull and turret elements to welding. At the same time, it turned out that the "PI" steel is completely unsuitable for this technology due to its poor weldability. The defect rate was so high that the plan for the production of T-26 and T-28 tanks was disastrously disrupted.
    Therefore, in 1933, the Izhora plant began to develop a new armor steel. Six formulations have been developed in succession. One of the 6 experimental ingots, from which the armor plates were made, showed, when fired at the range, bullet resistance, superior to the armor of "PI". The main alloying elements were silicon, manganese and molybdenum. The cost of the new steel was lower than the previous armor.
    To confirm the manufacturability and bullet resistance of the new steel, two open-hearth melts were cast. Armor plates were made from these heats.
    Based on the results obtained, in agreement with the Main Artillery Armored Directorate (GABU), the new steel was named "IZ" and instead of "PI" steel "IZ" went into production.
    This steel, with minor upgrades, was used as intended until the 1970s. Even today you can find bullet-resistant steel "2P", based on the recipe "IZ"
    1. Selevc
      Selevc 15 October 2020 13: 47
      -2
      In the last decade before the war, the appearance abroad of armor-piercing artillery in calibers from 20 to 50 mm was a serious challenge.
      Sorry, 20mm is the caliber of anti-aircraft machine guns of air defense .... Naturally, by the beginning of the Second World War, with such a caliber, it was possible to shoot only lightly armored targets such as a truck, a wedge, an armored personnel carrier.

      But we must understand that tanks for quite a long time were conceived and designed only as fire support for the advancing infantry and cavalry - therefore, they were originally designed to be fast and with bulletproof armor.
      1. Undecim
        Undecim 15 October 2020 13: 54
        +4
        Sorry
        Sorry, but who are you apologizing to?
      2. NDR-791
        NDR-791 15 October 2020 14: 28
        +7
        Sorry, 20mm is the caliber of anti-aircraft machine guns ...
        How so ??? Tell our infantry at 41m.
        1. Selevc
          Selevc 15 October 2020 14: 38
          +2
          Sorry, 20mm is the caliber of anti-aircraft machine guns ...
          How so ??? Tell our infantry at 41m.
          So what ??? Your photo confirms 200% of my words !!! This was created precisely as a mobile firing point - to support the infantry !!! And then, on the very eve of World War II, the Germans and ours figured out this to combine with more powerful tanks into an armored fist and thus break through the front.
          And in general, in a real battle, artillerymen need a weapon that is effective against all types of armored vehicles - anti-aircraft air defense machine guns are an extremely extraordinary case of their use against armored personnel carriers or tanks - from hopelessness and at least an extreme situation ...
          1. NDR-791
            NDR-791 15 October 2020 14: 53
            +4
            It's just this: 20mm is the caliber of anti-aircraft air defense machine guns sounded too categorical, maybe I just misunderstood your message, but still not only air defense. They were created completely for "earthly" purposes.
            ShVAK Aviation Gun

            Tank gun KwK30 L / 55

            Tank gun TNSh-20 (TNSh-1)
            1. Selevc
              Selevc 15 October 2020 15: 09
              -1
              categorically, maybe I just misunderstood your message, but still not only air defense. They were created completely for "earthly" purposes.
              ShVAK Aviation Gun
              The fact that the Wehrmacht was terribly called the T-2 tank in the USSR, no one at all considered a tank !!! So - wedge - reconnaissance in force or fast fire support for infantry. That is, a means for solving narrowly focused tasks ... It must be assumed that the "Versailles noose" still strangled Germany. even before the start of World War II - this can be seen from the lag of pre-war Germany in tank building ...
              1. yehat2
                yehat2 15 October 2020 15: 40
                +5
                t2 had armor up to 30 mm, and our tankettes were only bulletproof, and even then not the most reliable.
            2. hohol95
              hohol95 15 October 2020 22: 35
              +2
              You missed the 20 mm Solothurn anti-tank missile system, which the Hungarians installed in the turret of their Toldi I light tank
              And the Italian 20-mm automatic cannon Breda 35. Tank tank L6 / 40 /
      3. Alexey RA
        Alexey RA 15 October 2020 14: 37
        +3
        Quote: Selevc
        Sorry, 20mm is the caliber of anti-aircraft machine guns of air defense .... Naturally, by the beginning of the Second World War, with such a caliber, it was possible to shoot only lightly armored targets such as a truck, a wedge, an armored personnel carrier.

        We read carefully:
        In the last decade before the war, the appearance abroad of armor-piercing artillery of calibers from 20 to 50 mm was a serious challenge.

        The last decade before the war began in the early 30s. In those days, 20-mm could easily fight tanks.
        And by the end of this last decade, a 25-mm anti-tank rifle was in existence.
        Quote: Selevc
        But we must understand that tanks for quite a long time were conceived and designed only as fire support for the advancing infantry and cavalry - therefore, they were originally designed to be fast and with bulletproof armor.

        It depends on where. The French, for example, built those silver carps. In our country, traditionally, the range of products produced was determined in many respects by the capabilities of the industry and the army budget. She mastered the BT and T-26 industry in the early 30s - and drove them to the last. KhPZ, pomnitsa, for the transition to the T-34 had to get a stick from Moscow.
        1. irontom
          irontom 15 October 2020 16: 10
          +1
          Here the silver carp came out conditionally thick-headed, because of the low quality of the French cast armor, even 40 mm of the R35's forehead could easily break through with a mallet at an effective fire distance of 400-500 m.What can I say, 25 mm Frenchwoman loved him perfectly.
      4. BAI
        BAI 15 October 2020 14: 44
        +6
        20mm is the caliber of anti-aircraft air defense machine guns

        20 mm is a cannon.
        1. Alexey RA
          Alexey RA 15 October 2020 16: 26
          +3
          Quote: BAI
          20 mm is a cannon.

          Not a fact, not a fact ... we had a "20-mm ShVAK machine gun" in our documents.
          Due to the fact that the ShVAK automation was originally designed for a 12,7 mm caliber, it was necessary to use an extremely light weight shell (20 grams against the normal weight for this caliber of 91-125 grams) and a short length for using a 150 mm cartridge. As a result, the projectile received reduced ballistic qualities, leading to a rapid loss of initial velocity.
          This circumstance leads to a significant decrease in armor penetration. 20 mm ShVAK machine gun and a reduction in the distance of anti-aircraft fire compared to the 12,7 mm machine gun

          © Chief of armaments and technical supplies of the Red Army, commander of the 2nd rank Khalepsky and chief of the Artillery Directorate of the Red Army, corps commander Efimov. "Information about 12,7 mm and 20 mm ShVAK machine guns."
          1. boris epstein
            boris epstein 15 October 2020 17: 34
            +1
            "In 1934, the 12,7 aircraft machine gun VG Shpitalny and SV Vladimirov ShVAK was adopted. During the development and testing, it became possible to make it bicaliber-12,7 and 20 mm. In 1936, the 20-mm SHVAK CANNON was created. ... "
            The source of the quotation is the book "Weapon of Victory", Moscow, "Mechanical Engineering", 1987, p. 286.
            1. Alexey RA
              Alexey RA 15 October 2020 17: 57
              +1
              Quote: Boris Epstein
              Source of quotation - the book "Weapon of Victory", Moscow, "Mechanical Engineering", 1987 year, page 286.

              1987 year. Then the terminology was already established.
              And in the 30s, 20-mm ShVAK was considered a machine gun not by anyone, but by the head of armament and technical supply of the Red Army and the head of the Artillery Directorate of the Red Army.
      5. boris epstein
        boris epstein 15 October 2020 17: 23
        +3
        20mm is the caliber of automatic cannons. The ammunition for them was filled with an explosive, in contrast to a bullet.
        1. Alexey RA
          Alexey RA 15 October 2020 17: 53
          +5
          Quote: boris epstein
          20mm is the caliber of automatic cannons. The ammunition for them was filled with an explosive, in contrast to a bullet.

          Bullets with explosives also exist quite well - the notorious MDZ.
      6. DrEng527
        DrEng527 15 October 2020 18: 00
        +3
        Quote: Selevc
        20mm is the caliber of anti-aircraft machine guns

        machine guns do not have such calibers - they are already cannons ... request
        "An artillery piece is a type of firearms with a caliber of more than 20 mm."
        1. Constanty
          Constanty 16 October 2020 15: 20
          0
          You're right
          Artillery gun - a type of firearms with a caliber more than 20 mm


          20 mm is no more than 20 mm laughing

          But seriously, 20 mm is the limit of classification, and some in the period before World War II treated such a weapon as a cannon (for example, Germany, as evidenced by the 2 cm KwK 30 L / 55 (2 cm Kampfwagenkanone 30 L / 55)), and some as a machine gun - for example, in Poland 20-mm weapons were called the heaviest machine guns - NKM - najcięższymi karabinami maszynowymi - for example Nkm wz. 38FK 20mm


          1. DrEng527
            DrEng527 17 October 2020 14: 02
            0
            Quote: Constanty
            in Poland, 20-mm weapons were called the heaviest machine guns -

            so this is Poland ... bully But seriously - you need to watch the projectile - maybe low-power? Derived from a heavy machine gun cartridge by replacing a bullet with a projectile? Many have sinned by this ...
            1. Constanty
              Constanty 17 October 2020 21: 07
              0
              In other comments I see that in some Soviet documents the 20mm ShVAK is indicated as a machine gun, not a cannon, just like the Finnish (and Hungarian) Lahti is an anti-tank gun, not a cannon. Therefore, the problem is not so obvious, regardless of the type of ammunition used.

              Ps. The heaviest Polish wz.38FK machine gun has Solothurn AG 20x138 mmB ammunition
              1. DrEng527
                DrEng527 19 October 2020 11: 02
                0
                ShVAK is noticeably weaker than 20 × 99 mm
                1. Constanty
                  Constanty 19 October 2020 14: 06
                  +1
                  Yes, but the caliber is 20 mm, and there was controversy about this.
                  In addition, not only in Poland, weapons with a caliber of 20 mm were attributed to machine guns.
                  In Japan (more precisely, in the Japanese navy), the guns "E shiki 1 gou" 99-1shiki (20mmx72RB) and "E shiki 2 gata" 99-2 shiki (20mmx101RB) were designated as kijuu (short for kikan juu or "machine gun"). ")
                  1. DrEng527
                    DrEng527 19 October 2020 14: 48
                    +1
                    THANKS FOR THE GREAT CONVERSATION! drinks
                    1. Constanty
                      Constanty 19 October 2020 22: 39
                      0
                      THANKS ALSO drinks
      7. The comment was deleted.
      8. Bormanxnumx
        Bormanxnumx 15 October 2020 19: 24
        +1
        Quote: Selevc
        Sorry, 20mm is the caliber of anti-aircraft machine guns of air defense .... Naturally, by the beginning of the Second World War, with such a caliber, it was possible to shoot only lightly armored targets such as a truck, a wedge, an armored personnel carrier.

        German 2cm FLAK-30, from a distance of 300m, could successfully "pick" our BTeshki, T-26, T-38, T-40, T-50.
        1. DrEng527
          DrEng527 17 October 2020 14: 04
          0
          Quote: BORMAN82
          from a distance of 300m, could successfully "pick" our BTeshki, T-26,

          and their 20K will make a T-2 hole from 1 km ... request
      9. Aviator_
        Aviator_ 15 October 2020 19: 28
        +4
        A machine gun is one that shoots bullets. And the bullet does not have a leading belt, their maximum caliber is 14,5 mm. German (more precisely, Swiss) anti-aircraft "Oerlikons" fired 20-mm shells with leading copper belts.
      10. Skyscream
        Skyscream 13 November 2020 11: 05
        0
        Machine gun - up to 20mm, from 20mm and above is considered a cannon. And here is an example of a close-caliber anti-tank gun: canon de 25 mm semi-automatique modèle 1934. In military air defense, the calibers 12,7 (DShK) and 7,62 (quad M4) were quite used.
  9. Kote Pan Kokhanka
    Kote Pan Kokhanka 15 October 2020 17: 15
    +3
    Quote: Alexey RA
    Due to the fact that ShVAK automation was originally designed for a 12,7 mm caliber, it was necessary to make a 20 mm cartridge for use in it shell extremely light weight (91 grams versus the normal weight of 125-150 grams for this caliber) and short length.

    Greetings dear Alexey!
    Here you are on the subtle path of collision. The author you mentioned himself is apparently confused, mentioning in one line both the cartridge, which is characteristic of machine guns, and the projectile, the characteristic difference between the cannon! Perhaps the reason for this was that the ShVAK was originally laid under a 12,7mm caliber, later fattened to 20mm. In this connection, the author of the lines refers initially to the machine gun cartridge, and then describes the Disadvantages of the cannon shell!
    In general, this misunderstanding was eliminated by the end of the 30s and in the documents it passed with a cannon, not a machine gun.
    An additional marker is the description of the sleeve. Everything is clear here.
    More interesting is the dispute over the German 15mm machine guns. There is an opportunity here for a discussion.
    1. Alexey RA
      Alexey RA 15 October 2020 17: 45
      +2
      Quote: Kote pane Kohanka
      The author you mentioned himself is apparently confused, mentioning in one line both the cartridge, which is characteristic of machine guns, and the projectile, the characteristic difference between the cannon!

      The commander said - a ferret! So - a ferret! And no gophers! © smile
      The chief of armaments and technical supplies of the Red Army and the chief of the Artillery Directorate, being in their posts, are infallible in matters of armament.
      Quote: Kote pane Kohanka
      Perhaps the reason for this was that ShVAK was originally laid under a 12,7mm caliber, later fattened to 20mm. In this connection, the author of the lines refers initially to the machine gun cartridge, and then describes the Disadvantages of the cannon shell!

      PMSM, that is why: 20-mm ShVAK made practically no changes from 12,7-mm ShVAK (so as not to touch the finally working automation and get by with minimal changes in the production process). Therefore, in the documents of the 30s, the 12,7-mm ShVAK machine gun and the 20-mm ShVAK machine gun pass.
      Quote: Kote pane Kohanka
      More interesting is the dispute over the German 15mm machine guns. There is an opportunity here for a discussion.

      Do not! belay
      1. Kote Pan Kokhanka
        Kote Pan Kokhanka 15 October 2020 18: 37
        +3
        So you confirm my version that ShVAK called it a 20mm machine gun by inertia. In the 40s they left this practice. In the 50s, this dispute was not returned. The ShVAK machine gun is 12,7 mm, the ShVAK cannon is 20mm!
        Quote from SVE for 1973, Moscow.
        ... The Yak-9TK with the M-105PF engine was a modification of the Yak-9T with the same engine and differed from it mainly in that for the first time it was possible to install four options (depending on the requirements of the Air Force) motor-guns: ShVAK 20 mm caliber, VYa-23 23 mm caliber, NS-37 37 mm caliber and NS-45 45 mm caliber.
    2. Bormanxnumx
      Bormanxnumx 15 October 2020 17: 52
      +3
      Quote: Kote pane Kohanka
      More interesting is the dispute over the German 15mm machine guns. There is an opportunity here for a discussion.

      For German machine guns, the discussion can start with the 13mm MG-131 - there the bullet also has a full set of shell "sex characteristics" lol
  10. DrEng527
    DrEng527 15 October 2020 17: 58
    +3
    Interesting and informative! love Advice to the author: it will more clearly give the composition of the armor in the table repeat , as well as heat treatment of various steels, indicating temperatures and terms .. hi
  11. Tests
    Tests 15 October 2020 22: 16
    +4
    A few months ago, the site has already discussed the welding of our tanks. 09.10.2020/34/XNUMX discussed how at SEVMASH they will build an APL using the new technology. And today again about tanks ... And again, the respected author managed to mix metallurgy and welding technology in the material ... So far, under the leadership of E.O. Paton did not introduce automatic submerged-arc welding - the T-XNUMX cracked. Almost any alloy can be brewed. BUT!!! This requires little things: selection of an electrode by chemical composition, by melting rate, selection of current (constant or variable), its strength and voltage, its polarity, a method of isolating the weld pool from the ambient air, a method of cutting the edges of the welded metal, welding directions, temperature and heating area of ​​the base metal and the same for the part to be welded, the number of passes with the electrode, the direction of welding, the method of cleaning the first pass of the weld and the root of the weld from slag and a lot of little things that are only interesting to the technologist - the welder ... It is not correct to hang all the dogs on the problems of armor for our metallurgists ... I repeat the thought that I wrote a few months ago: we defeated Germany and, together with her, the whole of Europe, also because we had the Paton Institute, but in Europe it was not.
  12. Constanty
    Constanty 16 October 2020 01: 26
    +2
    Nevertheless, until the early 30s, cemented armor found use as in aviation, and in tank building. In aircraft, armor plates up to 13 mm thick were cemented,


    Excuse me, which models of Soviet aircraft (because it follows from the context) had armor plates 13mm thick before 1930?
  13. Essex62
    Essex62 16 October 2020 14: 52
    0
    Very interesting, informative article. I will highlight the non-technical aspect. What a great hard work the Soviet People were given to equip, in the pre-war years, the Red Army with armored vehicles. And how stupidly the "military leaders" squandered, at the beginning of the Second World War, all this wealth. The idiots - liberoids accuse Stalin and his associates of bloody lawlessness in 37 and in subsequent. If only the frank contradiction had not been cleared out, it would be scary to imagine what would have happened. For crimes in the initial period of the Second World War, except for Pavlov, with the headquarters against the wall, almost no one was leaned against. Uniquely. For the loss of all European territory and all armor and aviation, it was necessary to spank hundreds of slobs and traitors. And these idiots Stalin is a bloody tyrant. Didn't touch, gave the opportunity to fix the matter.
  14. Constanty
    Constanty 16 October 2020 15: 11
    +1
    In the next article, the author writes about steel 8C as about the high hardness steel used in the T-34, while the hardness of the steel from which these tanks were made during the war was only 250-280 points on the Brinell scale. Even pre-war products averaged around 320 on the Brinell scale, so low that they could be characterized as high-hardness steel.