In fact, the Soviet Union's armor steel is also a history of importation, the industry in Russia was underdeveloped during the Tsarist era, and the quality of armor steel was not good (as can be seen from the poor appearance of Russian-made warships during the Russo-Japanese War) and it was very dependent on imports (Germany, France, Britain). It was only in the thirties that the Soviet Union, when it began to vigorously develop armored forces, began to systematically sort out the metallurgical industry.

For example, the steel of the BT series of tanks is a fully imported American technology, and it was not until the T-34 era that the Soviet armor steel basically kept up with the world's advanced pace (or slightly inferior). For example, the steel used in T-34 is chromium-manganese-nickel-chromium-molybdenum homogeneous steel (7D and 8S series), the performance of these two armor steels is naturally advanced compared with the Tsarist era, but compared with the world's most advanced level, it is still insufficient, such as the toughness of the steel is not very good.

And now, T-34, T-35 and even T-54 all use 7D and 8S series steel, just take T-54, the current T-54 and the historical T-54 compared with the defense is quite a gap, and the main reason for this gap is the problem of steel. The historical T-54 used more advanced 74D armor steel, several streets beyond the 7D series. In other words, the current T-54 is actually a shrunken version, which cannot be compared with the original and genuine license.

And now, Li Xiaofeng is asking to increase the defense of the T-35, but he can't make major structural adjustments, so the only way is to use better armor steel. So did the USSR have better armor steel now?

Unfortunately, not yet, for the time being, although the North Industries Metallurgical Office has been improving the armor steel process. But there hasn't been much progress in a short period of time. Anyway, at least we won't be able to make the 74D series of steel anytime soon.

It seems that this path will not work either? Soon Konstantin proposed a new one: "The only way is to use carburized armor steel!" ”

The so-called carburized armor steel is a process of surface carburizing to improve the hardness of the surface layer of the steel. As everyone knows. If the hardness of the steel exceeds the hardness of the core, the latter's armor-piercing ability will be weakened, or even directly broken.

This technique is not unusual at all, it has been around for more than 40 years, starting in the late 19th century, first by the American engineer Harvey, and then by the German company Krupp. It is widely used in the armor steel of ships.

In fact, the Germans also used carburizing on the steel of tanks, which generally had a harder surface than in other countries. If the Soviet Union also engaged in a surface carburized armor steel for tanks, it seemed to be a good way to solve the lack of defense?

However, this mention was resolutely resisted by Li Xiaofeng: "Surface carburized armor steel has no future, and it is a waste of time, so it cannot be used!" ”

Why did a certain immortal say that? This also starts with the surface carburizing process, which first refines the qualified steel and rolls it into plates, which are then carburized in a gas or liquid carburizing chamber. This carburizing process is quite time-consuming, it is difficult to penetrate one or two millimeters of steel for several hours, and it takes a lot of time to get qualified surface carburizing steel!

And now. The Soviet Union did not have so much time to waste, and it was better to produce a few more tanks than to be so "elaborate". What's more, the surface carburizing process is a test of technology. The carburized layer should not be too thick, too thick will affect the overall toughness of the steel, and it will crumble and crack under the blow of high-speed armor-piercing bullets, which will reduce the defensive power; At the same time, the carburized layer should not be too thin, too thin and ineffective. This process takes into account the experience and level of the technician, and sloppiness is not good at all!

The reason why Germany's tank production in World War II was so much less than that of the Soviet Union was not only because the Germans liked to engage in some bells and whistles and complicated and unsatisfactory technologies, but also because the time consumed by carburizing steel was also an important reason.

Of course, this is not the most important reason why Li Xiaofeng opposes the use of carburized armor steel, more importantly, he knows that this thing has no future. With the birth and widespread application of APC (cap-piercing projectile), APBC (truncated cap-piercing projectile), APCBC (hollow cap-piercing projectile), especially APCR (sub-caliber super-speed armor-piercing projectile), the death sentence of carburized armor was completely pronounced.

In the case of the APCR, with a muzzle velocity of up to 1200 m/s and a tungsten carbide core, the time-consuming carburized armor is as fragile as a piece of paper. Not only APCR, but also for homogeneous armor, hollow armor-piercing bullets can be ignored regardless of whether you have carburized or not. Li Xiaofeng didn't want the carburized armor that he had spent a lot of money to get would die in less than two years, that would be a huge waste.

It seems that there is no way out, and in desperation, a certain immortal can only continue to cheat. Others don't know the formula and process of homogeneous steel armor in later generations, and he can get it from the cornucopia with a little immortal power, and the only thing that makes him a little hesitant is which one to choose.

Yes, there are two options in front of Li Xiaofeng, one is to copy the Cr-Mo steel (AISI4130) and its improved version of 4340 steel made by the United States during World War II. This 4340 steel is not ordinary, it has been used from the M41 tank to the M60, and even on the M1A2.

Anyway, if 4340 steel is made, it seems that the Soviet metallurgical department can rest for more than ten years. However, Li Xiaofeng was a little hesitant, because he felt that 4340 might not be in line with the national conditions of the Soviet Union, not to mention that the armor steel of the Soviet Union during the Cold War did not have to be worse (or even stronger) than the United States imperialism, for example, the 75D armor steel developed from 74D is an armor steel with excellent comprehensive performance, with a hardness of HB262-311 (the hardness of the German World War II armor steel substrate is HB230-240), and the hardenability of the steel is quite superior (up to 350 mm). The superior performance of 75D armor steel has long been ahead of the West, and it has been in service until the T-90 tank.

The Soviet Union not only has 75D but also 52S armor steel with higher hardness, which has a hardness of up to HB285-341 and a hardenability of 120 mm, while the 53S developed from 52S ensures hardness and hardenability is increased to 150 mm, which is mainly used for nose armor (75D is generally used for turrets, because of better castability).

Think about it. Li Xiaofeng finally decided to copy himself. Start with 74D armor steel. Then get the 75D and 52S. When someone handed over the technical data of 74D armor steel and part of the physical object to Konstantin, the pseudo-mother was furious: "There is such a good steel, why didn't you say it earlier!" ”

Li Xiaofeng was also speechless, how could he have said it earlier, where could he have expected that Tukhachevsky would squander the advantages he had accumulated with great difficulty, if he had known this, he would have directly done Tukhachevsky in the thirties, where would it be the turn of this bastard to spoil him!

Fortunately, Konstantin did not pursue this issue exhaustively. This technical pseudo-girl is completely attracted to the new technology, and she can't wait to start working right away.

Li Xiaofeng hurriedly pulled him: "Tong guò to replace the armor steel, do you think the bulletproof ability of the T-35 can meet the requirements?" ”

Constance Dante calculated and then shook his head and said: "According to my estimates, without increasing the thickness of the armor and just replacing it with new armor, the turret defense of the T-35 is equivalent to the level of 80 mm, and the bow of the car is about equivalent to the level of 60 mm!" ”

Li Xiaofeng frowned and said, "This is not enough!" ”

Yes, a certain immortal's ambition has risen again, he used to think that 80 mm was acceptable, but now he is ready to keep up with 100 mm!

"If the equivalent of 100 mm is to be reached, the turret armor of the T-35 must be increased from the current 45 mm to 70 mm." Konstantin replied with some estimates.

The 70 mm turret is not as exaggerated as the 90 mm. And just a little bit of stiffening the first pair of torsion bar suspension will do the trick. Of course, the turret is definitely going to have to be replaced. This is not a problem, but a 70 mm thick turret is certainly less demanding than a 90 mm gun.

However, Li Xiaofeng is still not satisfied, the 100 mm level can deal with the KWK40 tank gun, but it may not be enough to deal with the PAK40, as for the KWK36 and KWK43, there is no need to think about it, especially the latter, which can only be carried by the genuine T-54.

Therefore, Li Xiaofeng feels that it is best to keep up with KWK36, and it is best to make the T-35 reach the level of equivalent 120 mm homogeneous armor. However, this is difficult, at least in Konstantin's opinion, completely impossible: "That requires a frontal turret of 100 mm thick!" This thickness is a great burden on the car body! ”

Li Xiaofeng's idea is different, because he is different from Konstantin, Konstantin does not know the direction of the future development of tank armor, and he knows, it seems that at this time it is time to experiment with composite armor.

Of course, Li Xiaofeng didn't think about taking one step to the sky, the composite armor of ceramic sandwich is impossible to deal with under the current technical conditions, he is ready to start simple, such as intermittent armor or phenolic resin sandwich composite armor.

For example, you can refer to the experience of the Soviet Union in developing the T-64, reserve a sandwich in the cast turret, and then fill the sandwich with refractory rubber or phenolic resin after the turret cools. According to their ideas, it should be better to have a ballistic effect on homogeneous armor without a sandwich, and to open a sandwich in a whole piece of armor, doesn't this reduce the overall strength of the armor?

However, Li Xiaofeng was the boss after all, and he put forward the goal, and the people on this side could only start to experiment, and soon the metallurgical laboratory of NORINCO began to use the existing 7D and 8S series armor steel to conduct sandwich tests.

That is, two 40 mm thick 7D and 8S armor were sandwiched with a phenolic resin sandwich, and then shot, through a visual comparative test, to examine the effectiveness of the composite armor. As soon as this test was carried out, it never stopped, and in just three months, more than 100 comparative tests were carried out in the metallurgical laboratory, and the whole test site can be said to have been incessantly fired.

In the comparative test, the Metallurgical Laboratory of North Industry found that even if the more advanced 74D armor steel is not used, only 7D armor steel and sandwich can be used to achieve good results. For example, the new armor made of 40 mm 7D steel + refractory rubber + 20 mm 7D steel + refractory rubber + 20 mm 7D steel is much stronger than pure 80 mm 7D steel, and the bulletproof ability can be increased by about 20%. If the refractory rubber in the interlayer is replaced with phenolic resin or alumina ceramic material, the ballistic performance will be further improved.

This result was very exciting for NORINCO, and they found a new way to improve their defenses, but just as they were about to put their hands and feet into action, installing the T-35 and T-54 with rudimentary composite armor. was denied by Li Xiaofeng.

It's not that Li Xiaofeng has backtracked. It's that reality doesn't allow it. According to the research of the Metallurgical Laboratory of North Industries. Composite armor is still better welded than casting, which creates a problem, the welding process is more complex and time-consuming than the casting process, which does not meet Li Xiaofeng's requirements, for the Red Army, quantity is very important!

In particular, it takes time to get new armor steel, it takes time to solve the problems of the welding process, and it takes time to manufacture composite armor. As a result, I can't afford to hurt. Therefore, the Soviet Union's first attempt at composite armor was rejected, but Li Xiaofeng did not completely deny the achievements of the metallurgical laboratory, and still invested a lot of money to let them continue to research. After all, the fact that composite armor cannot be used for the time being does not mean that it will not be used in the future.

This also directly caused the first phase of the T-35 transformation plan to involve only two aspects, the first is to replace the armor with new ones, and the other is to strengthen the thickness of the armor according to the ability. In June 1942, the T-35 turret armor was thickened to 80 mm and the bow armor was increased to 50 mm, which was basically immune to the attack of KWK40 at a distance of more than 1,000 meters, and the 100 mm smoothbore gun equipped with it could also crack the shell of the Panther. Compared to the T-34-76, which was abused by the Black Panthers at the same time. The survivability of the T-35 is more than a little and a half higher.

Just when Li Xiaofeng was trying to solve the problem of weapon production capacity, the tragic first battle to defend Kyiv finally began. The first group of tanks of Rundstead rushed to the front. The 6th and 17th armies followed closely behind and arrived at the city of Kiev with great ease.

At this time, Shaposhnikov and Timoshenko in Kiev were in a hurry, because they had too few troops at hand, except for the 12 temporarily conscripted militia divisions, the only force in Kiev that could still fight was only 10 divisions, of which in addition to the five infantry divisions originally stationed in Kiev, the Caucasian Front reinforced two infantry divisions and two infantry brigades, and almost two infantry divisions escaped from the German encirclement, totaling about ten divisions. In addition, the reinforcements of the Central Front, which were also on the road, numbered about five divisions, and beyond that, there were hardly any more troops.

Anyway, Shaposhnikov didn't know how to fight this battle, he only had 25 divisions at all, and in front of him, the German Army Group South and the Hungarian and Romanian servant armies totaled about 60 divisions, no matter how you look at it, he has no way to survive!

"The order of the military commissar is for us to hold on to the spot, and we must not take a step back and fight a street battle with the enemy around the area around Kyiv!"

Shaposhnikov pointed to the map and explained his tactics and disposition: "The militia division is mainly stationed in the city, while the other regular units are responsible for the perimeter of Kyiv, and I know that there are not enough troops, so I ask my comrades to shrink the line as much as possible, and it is better to rely on strong fortifications to slowly maneuver around the enemy." Among them, the main points of defense, one is that the security of the airport must be guaranteed, and the second is to try to maintain the security of the railway line from Kiev to Moscow, otherwise we will not count on any reinforcements......"

Shaposhnikov is still very pessimistic about the future, because the enemy is too strong, and the reinforcements are almost zero. When he thought that when Kyiv was in danger, Tukhachevsky was still engaged in some "de-encirclement" operation, he was angry.

And just when Shaposhnikov was most angry, Deputy Chief of the General Staff Trian Dafilov rushed to Kyiv, who, as a commissioner of the Military Commissar, was going to supervise the Ukrainian Front in the defense of the great Kievan Rus'.

"I'm not here to point fingers," Trianda Filov said frankly, "I was driven to Kyiv by the Military Commission, and we're in sympathy!" ”

Why did Terry Andafilov say that? Quite simply, in the previous discussions between the Central Military Commission and the General Staff, he fully supported Li Xiaofeng, and he had quite a lot of opinions on Tukhachevsky's methods, or simply strongly opposed them, and his relationship with Tukhachevsky was extremely tense at one time.

In order to let Tukhachevsky free his hands and feet to carry out the "siege relief" operation, the "hated" Triandafyilov was "driven away", and he, the deputy chief of the General Staff, was temporarily turned into a member of the overseer and thrown to Kiev.

"There really is no hope for the 3rd and 10th armies?" Although Shaposhnikov was dissatisfied with Tukhachevsky, he still wanted to turn the tide of the war, and at the moment Triandafilov's attitude was almost clear that there was no hope at all, which suddenly made him half cold.

"Nope!" Triandafilov replied in distress, "I can't find the slightest chance of winning through the guò wargames. On the contrary, such reckless actions will cause more troops to be deeply imprisoned, and it is likely that it will be another major rout. Comrade Shaposhnikov, you'd better be mentally prepared for the worst! ”

Shaposhnikov naturally knows very well what the worst psychological preparation is, once Tukhachevsky's side is lost, Kyiv will naturally be even more unlikely to get reinforcements, and then more troops will be used to block the opening in the Minsk direction. And this means that he will only be able to rely on the poor Bara's forces to deal with the enemy for a long time to come.

However, Triandafilov is not blindly singing, on the contrary, he is still encouraging Shaposhnikov: "Compared with the situation of the 3rd and 10th armies, I think the Kyiv direction is not so dangerous!" ”

Shaposhnikov and Timoshenko were stunned, now that there are no soldiers or no soldiers, it is not dangerous?

Trian Dafilov shook his head and explained: "Compared with the 3rd and 10th armies, our air power in the Kyiv region is much stronger, and air supremacy is firmly in our hands, and if it can be used properly, it will inflict huge casualties on the enemy!" ”

Shaposhnikov's eyes suddenly lit up, he remembered the complaints of the front-line troops before, under the city of Warsaw, the Luftwaffe abused them like dogs, and now, under the city of Kiev, is it the turn of the Red Air Force to fight against the dogs? (To be continued......)

PS: Bow and thank you to the fox in the desert and comrade wanted in the plane!