This is how tank hulls are tempered

In this issue we will tell you why the Germans built their tanks "square". What are the most tenacious hull manufacturing methods? And what happens inside the tank when the projectile hits the target but does not penetrate?

The largest and, undoubtedly, the main part of the tank is the hull. It must provide accommodation and reliable protection for the crew, weapons, mechanisms and other systems of the combat vehicle. Until the second half of the last century, armor steel served as the material for the manufacture of the case. Due to heat treatment or the addition of special alloying elements to the composition, it was much stronger than usual.

Armor steel appeared long before tanks, in the middle of the 19th century. It was most widely used in the construction of warships. The hull assembly technology was also borrowed from shipbuilding: armor plates were attached to the frame with bolts and rivets. At the same time, the riveted connection had a number of disadvantages. The frame on which the armor was attached had to be made of good steel and be quite powerful, which gave rise to an excessive mass of the tank. In addition, the frame took up extra space inside the combat vehicle. At the same time, the assembly of the hull was very time consuming, and the rivets and bolts had a bad property: if the rivet head was destroyed from the outside, the part could “shoot” inside the tank, causing damage. But, despite the listed problems, riveted and bolted connections were used until the 40s of the twentieth century.

With the development of technology, all the states that built tanks gradually abandoned the frame assembly in favor of more durable and rigid hulls assembled by welding or casting. Such structures themselves were "load-bearing", they could confidently perceive dynamic loads and not deform at the same time. The assembly of casings from cast elements, as well as casings cast entirely as one piece, were widely used from the 30s to the 60s of the last century. However, the cast armor was inferior to the welded method. So over time, it was the welding of parts that became the generally accepted method of manufacturing the body.

Its shape is of great importance for the survivability of the tank. In particular, armor plates installed vertically are less resistant to projectiles than those placed at an angle. This became especially noticeable when specialized anti-tank artillery became widespread. The Germans, who built their tanks "square" for most of the Second World War, did not do this because they did not know about the existence of rational tilt angles. It was a deliberate sacrifice in favor of manufacturability, ease of assembly and maintenance.

The last German tanks of the war period - "Panther" and "King Tiger" - were already defended by armor located at an angle. In addition to being resistant to enemy shells, a tank's hull must be strong and rigid enough to cope with the stresses that arise during operation. For example, large-caliber guns, which began to be used on tanks from the late 30s, create such a powerful recoil when fired that it is capable of deforming the body of a combat vehicle. The same thing threatens an insufficiently rigid body from many other influences - detonation on mines, hits of shells that did not pierce armor, aerial bombs and land mines that exploded nearby.

When designing the hull, it is very important to correctly place the hatches, both for the crew members and technical ones. Any hole, even if covered with an armored sheet, weakens the protection, and therefore there should not be too many of them, but sacrificing the convenience of access to the engine or risking the lives of tankers is also not worth it. The most famous Soviet tank of the Great Patriotic War, the T-34, had a large mechanical drive hatch in the front plate. This was one of the most vulnerable points of the 34 early modifications - until the spring of 1943. By hitting a shell, the hatch was often literally hammered inside, while the mechanic died. The new T-44 medium tank got rid of this "Achilles heel" only at the stage of mass production, after the war. And in the future, the hatches of the mechanics in Soviet tanks were located on the roof of the hull, and not in the frontal armor plate.

After the war, along with the development of anti-tank weapons, the shape of the corps gradually lost its former importance for protection. New armor-piercing sub-caliber or cumulative projectiles, capable of penetrating up to 70 centimeters of armor, were not hindered by inclined armor plates. Now for tanks, active, mounted and dynamic protection is much more important. Only after passing all these three "lines of defense", the projectile will reach the armor of the main body. Which has long been a complex of the most modern solutions in metallurgy and materials science. Armor is the outer shell of a combat vehicle, the main task of which is to reflect enemy projectiles. But the armor also has a downside, directed towards the crew. In the comments under the previous video, you asked: what happens inside the combat vehicle when the projectile still hits the target, but no penetration happened? It's time to answer the questions about the reservation action! Projectiles affect armor in different ways.

Kinetic ammunition — armor-piercing “blanks” and cores of sub-caliber ammunition — pierce it with the blow of their durable body. The cumulative ones do the same with a directed stream of gases under enormous pressure.

High-explosive fragmentation acts with an explosion. In any case, regardless of whether the armor was pierced or not, the shells have the effect of the armor action. An impact or explosion on armor often results in chunks of metal chipping off the inside. Their speed can be sufficient to destroy the tankers or damage the internal components of the tank. Upon penetration, the situation is aggravated - the projectile and armor give a lot of red-hot fragments piercing the fighting compartment of the damaged vehicle. They are capable not only of causing mechanical damage, but also of causing a fire. The cumulative jet that pierced the armor is also not a gift: it passes through the armor and the insides of the tank until it dissipates. In addition, its temperature is enormous — the tank can catch fire from the inside, and ammunition can explode.

The fight against the reserve action is carried out in different ways. First, they avoid hardening the inner layers of the armor, as the harder armor crumbles more. Secondly, various linings on the inner side are widely used. They are needed to catch small fragments bouncing from the inside of the armor plate when not penetrated. Lining materials can be different: rubber, asbestos, nowadays - various polymers. But to this day, the armor effect remains one of the deadly enemies of the tank and its crew.