Testing German Armor: Theory and Practice
The Royal Tiger at the Kubinka firing range immediately after shelling with 75 mm and 85 mm shells. Prior to this, more serious artillery worked on the Hitler machine. Source: warspot.ru
Objects of research
The German school of tank building, of course, one of the strongest in the world, required careful study and understanding. The first portion stories examples of tests of captured Tigers and Panthers were examined, but no less interesting documents could also fall into the hands of domestic engineers, according to which it was possible to trace the evolution of German technology. Soviet specialists during the war and later tried not to let anything out of sight. After most tanks Hitler’s “menagerie” was fired from all kinds of calibers, it was the turn of a detailed study of tank production technologies. In 1946, engineers studying the production technology of tracked tracks of German tanks finished their work. The research report was published in 1946 in the then-secret "Bulletin of the tank industry."
Source: metspra.ru
The material, in particular, indicates a chronic lack of chromium, which German industry had encountered in 1940. That is why in the Hadfield alloy, from which all the tracks of the tanks of the Third Reich were cast, there was no chrome at all, or (in rare cases) its share did not exceed 0,5%. The Germans also had difficulty obtaining ferromanganese with a low phosphorus content, so the share of non-metal in the alloy was also slightly lowered. In 1944, in Germany there were also difficulties with manganese and vanadium - due to overspending on armor steels, so the trucks were cast from silicon-manganese steel. Moreover, manganese in this alloy was not more than 0,8%, and vanadium was completely absent. All tracked armored vehicles had cast tracks, for the manufacture of which arc electric furnaces were used, with the exception of plain tractors - stamped tracks were used here.
Caterpillar of the Mouse. Cuban. Author photo
An important step in the manufacture of tracked tracks was heat treatment. In the early stages, when the Germans still had the opportunity to use Hadfield steel, the trucks slowly heated from 400 to 950 degrees, then for a while they raised the temperature to 1050 degrees and quenched in warm water. When it was necessary to switch to silicon-manganese steel, the technology was changed: the tracks were heated to 980 degrees for two hours, then cooled to 100 degrees and quenched in water. After that, the smelting of the trucks at 600-660 degrees for two hours was still released. Often, specific treatment of the track ridge was applied, cementing it with a special paste followed by water quenching.
The largest German supplier of tracks and fingers for tracked vehicles was Meyer und Weihelt, which together with the Wehrmacht’s High Command developed a special technology for testing finished products. For trucks, it was a bend to failure and multiple impact tests. Fingers were tested for bending to fracture. For example, the fingers of the tracks of the TI and T-II tanks, before they burst, had to withstand a load of at least a ton. Residual deformations in accordance with the requirements could appear at a load of at least 300 kg. Soviet engineers noted with perplexity that the plants of the Third Reich did not have a special procedure for testing the tracks and fingers for wear resistance. Although it is this parameter that determines the survivability and resource of tank tracks. This, by the way, was a problem for German tanks: the truck’s lugs, fingers and ridges wore out relatively quickly. Only in 1944 in Germany began work on the surface hardening of eyes and ridges, but time was already lost.
"Royal Tiger" under fire. Source: warspot.ru
How was time lost with the advent of the Royal Tiger? The optimistic tone that accompanies the description of this vehicle on the pages of the Bulletin of the Tank Industry at the end of 1944 is very interesting. The author of the material is lieutenant colonel engineer Alexander Maksimovich Sych, deputy head of the Kubinka test site for research and development activities. In the post-war period, Alexander Maksimovich rose to the rank of deputy chief of the Main Armored Directorate and oversaw, in particular, tank tests for resistance to atomic explosions. On the pages of the main specialized publication on tank building A. M. Sych describes a heavy German tank not from the best side. It is indicated that the sides of the tower and hull are affected by all tank and anti-tank guns. Only the distances are different. Cumulative shells took armor from all ranges, which is natural. Sub-caliber 45-57-mm and 76-mm shells hit at distances of 400-800 meters, and armor-piercing caliber 57, 75 and 85 mm - from 700-1200 meters. It must only be remembered that A. M. Sych under the defeat of the armor does not always imply its through penetration, but only internal spalls, cracks and open joints.
The forehead of the “Royal Tiger” was expectedly struck only by calibers of 122 mm and 152 mm from distances of 1000 and 1500 meters. It is noteworthy that the material also does not say about the non-penetration of the frontal part of the tank. During the tests, 122-mm shells caused spalls on the back of the plate, destroyed the machine gun course, cracked the welds, but did not pierce the armor through at the indicated distances. This was not a matter of principle: the obstructed action of an incoming projectile from the IS-2 was quite enough to guarantee the failure of the car. When the 152-mm ML-20 cannon was working on the forehead of the Royal Tiger, the effect was similar (without penetration), but cracks and open joints were larger.
As a recommendation, the author suggests conducting machine-gun fire and firing from anti-tank rifles at the observation instruments of the tank - they were dimensional, unprotected and difficult to change after a defeat. In general, according to A.M.Sych, the Germans hurried with this armored vehicle and counted more on the moral effect than on the fighting qualities. In support of this thesis, the article says that during production the pipeline was not fully assembled to increase the fordability to be overcome, and the instructions in the captured tank were typewritten and in many ways did not correspond to reality. At the end, the Tiger II is rightly blamed for being overweight, while the armor and weapons do not correspond to the “format” of the machine. At the same time, the author accuses the Germans of copying the form of the hull and turret T-34, which once again confirms the world the advantages of the domestic tank. Among the advantages of the new "Tiger" stand out carbon dioxide automatic fire extinguishing system, a monocular prismatic sight with a variable field of view and an engine heating system with battery for reliable winter starting.
Theory and practice
All of the above clearly indicates that the Germans at the end of the war experienced certain difficulties with the quality of tank armor. This fact is well known, but methods of solving this problem are of interest. In addition to increasing the thickness of the armor plates and giving them rational angles, the Hitlerite industrialists went to certain tricks. Here you will have to delve into especially the technical conditions by which the molten armor was taken for the production of armored plates. “Military Acceptance” conducted a chemical analysis, determined the strength and conducted firing range. If everything was clear with the first two tests and it was almost impossible to dodge here, then shelling at the firing range since 1944 has caused a steady "allergy" among industrialists. The thing is that in the second quarter of this year, 30% of the shells tested by shelling could not stand the first hits, 15% became substandard after the second projectile hit, and 8% were destroyed from the third test. This data applies to all German plants. The main type of marriage during the tests was spalling on the back of the armor plates, the size of which exceeded the projectile caliber by more than two times. Obviously, no one was going to revise the acceptance standards, and improving the quality of armor for the required parameters was no longer under the strength of the military industry. Therefore, it was decided to find a mathematical relationship between the mechanical properties of armor and armor resistance.
Initially, the work was organized on E-32 steel armor (carbon - 0,37-0,47, manganese - 0,6-0,9, silicon - 0,2-0,5, nickel - 1,3-1,7 , chrome - 1,2-1,6, vanadium - up to 0,15), according to which statistics from 203 shells were collected. The thickness of the plate was 40-45 mm. The results of such a representative sample showed that only 54,2% of the armored plates withstood shelling by 100% - all the rest for various reasons (spalling on the back, cracks and splits) failed the tests. For research purposes, the fired specimens were tested for tensile strength and impact resistance. Despite the fact that the relationship between mechanical properties and armor resistance, of course, exists, the E-32 study did not reveal a clear relationship, which allows abandoning field tests. The armor plates, fragile by the results of the shelling, revealed high strength, and those that did not pass the back strength tests found a slightly lower strength. It was not possible to find the mechanical properties of the armor plates, which make it possible to distinguish them into groups according to armor resistance: the limiting parameters went far into each other.
The question was approached from the other side and adapted for this purpose the dynamic torsion procedure, which was previously used to control the quality of tool steel. The samples were tested before the formation of kinks, which, among other things, indirectly judged the armor resistance of the armor plates. The first comparative test was carried out on E-11 armor (carbon - 0,38-0,48, manganese - 0,8-1,10, silicon - 1,00-1,40, chromium - 0,95-1,25) using samples that successfully passed the shelling and failed. It turned out that the torsion parameters of the armored steel are higher and not very scattered, but in the "bad" armor, the results obtained are significantly lower with a large dispersion of the parameters. A break in high-quality armor must be smooth without chips. The presence of chips becomes a marker of low shell resistance. Thus, German engineers managed to invent methods for assessing the absolute armor resistance, which, however, they did not have time to use. But in the Soviet Union, these data were rethought, large-scale research was carried out at the All-Union Institute aviation materials, VIAM) and was adopted as one of the methods for assessing domestic armor. Trophy armor can be not only in the form of armored monsters, but also in technologies.
Frontal detail of the Mouse with marks. Cuban. Author photo
Of course, the apotheosis of the captured history of the Great Patriotic War became two copies of the super-heavy "Mouse", of which at the end of the summer of 1945, Soviet specialists assembled one tank. It is noteworthy that after studying the machine by the specialists of the NIABT training ground, they practically did not fire at it: obviously, there was no practical sense in this. Firstly, in 1945 the Mouse was no longer a threat, and secondly, such a unique technique was of certain museum value. The power of domestic artillery at the end of testing at the test site from the Teutonic giant would leave a pile of debris. As a result, the Mouse received only four shells (obviously, 100 mm caliber): to the forehead of the hull, to the right side, to the forehead of the tower and the right side of the tower. Attentive visitors to the museum in Kubinka will probably be outraged: they say, on the armor of the Mouse there are much more marks from the shells. These are all the results of shelling with German guns back in Kummersdorf, and the Germans themselves fired during the tests. To avoid fatal damage, domestic engineers carried out calculations of the armor resistance of the tank protection according to the Jacob de Marr formula, as amended by Zubrov. The upper limit was a 128 mm shell (obviously German), and the lower limit was a 100 mm shell. The only part that can withstand all these ammunition was the 200-mm upper frontal, located at an angle of 65 degrees. The maximum reservation was at the forehead of the tower (220 mm), but theoretically due to the vertical position it was hit by a 128-mm shell at a speed of 780 m / s. Actually, this shell at various speeds of approach penetrated through the tank armor from any angle, except for the frontal part mentioned above. The 122-mm armor-piercing projectile from eight angles did not penetrate the Mouse in five directions: into the forehead, side and rear of the tower, as well as into the upper and lower frontal part. But we remember that the calculations are carried out for the through defeat of the armor, and even a high-explosive 122-mm shell without penetration could well disable the crew. To do this, it was enough to get into the tower.
In the results of the study of Mouse, one can find the disappointment of domestic engineers: this giant machine did not represent anything interesting at that time. The only thing that attracted attention was the method of connecting such thick armor plates of the hull, which could come in handy when designing domestic heavy armored vehicles.
The “Mouse” has remained to the end an unexplored monument to the absurd thought of the German engineering school.
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