Skyrim steel armor. The influence of the hardness of steel armor on its resistance to projectiles. Rolled homogeneous armor

Ship armor- a protective layer that has sufficiently high strength and is designed to protect parts of the ship from the effects of enemy weapons.

History of origin

Before early XIX century, shipbuilding maintained a certain balance between means of defense and attack. The sailing ships were armed with smooth-bore muzzle-loading guns that fired round cannonballs. The sides of the ships were lined with a thick layer of wood, which protected them quite well from cannonballs.

The first to protect the ship's hull with metal shields was the British inventor Sir William Congreve, who published his article in the London Times on February 20, 1805. A similar proposal was made in the USA in 1812 by John Steveno from Hoboken (New Jersey). In 1814, the Frenchman Henri Peksan also spoke about the need to book ships. But at the same time, these publications did not attract attention.

The first iron ships that appeared at that time - the steam frigates Birkenhead (Eng. HMS Birkenhead (1845)) and "Trident" (English HMS Trident (1845)) built for the British fleet in 1845 were received quite coldly by the sailors. Their iron plating protected against cannonballs worse than wooden plating of the same thickness.

Changes in the current state of affairs occurred in connection with progress in artillery and metallurgy.

Back in 1819, General Peksan invented an explosive grenade, which upset the existing balance between protection and projectile, since wooden sailing ships were subject to severe destruction from the explosive and incendiary effects of the new weapon. True, despite the convincing demonstration of the destructive properties of the new weapon in 1824 during test firing on the old two-deck battleship Pacificator (English French ship Pacificateur (1811)), the introduction of this type of weapon was slow. But after the phenomenal success of its use in 1849 at the Battle of Ekern Fiord and in 1853 at the Battle of Sinop, doubts disappeared even among its greatest critics.

Meanwhile, ideas for building armored ships were developing. In the USA, John Stevens and his sons, at their own expense, carried out a series of experiments in which they studied the laws of the passage of nuclei through iron plates and determined the minimum thickness of the plate required to protect against any known artillery piece. In 1842, one of Stevens' sons, Robert, presented the results of experiments and a new design for a floating battery to a Congressional committee. These experiments aroused great interest in America and Europe.

In 1845, the French shipbuilder Dupuy de Lome, on instructions from the government, developed a project for an armored frigate. In 1854, the floating battery of Stevens was laid down. A few months later, four armored batteries were laid down in France, and a few months later, three in England. In 1856, three French batteries - "Devastation", "Lave" and "Tonnate", invulnerable to artillery fire, were successfully used to bombard the Kinburn forts during the Crimean War. This successful application experience prompted the leading world powers - England and France - to build armored seaworthy ships.

Iron armor

The only metal suitable for practical use and available in sufficient quantity at that time was wrought iron or cast iron, and all experiments showed that wrought iron, with the same weight, had an advantage over cast iron. Wrought iron was used in the first armored ships, which were protected by 101-127 mm thick plates attached to 90 cm thick wooden beams. The most extensive experiments to improve the strength of iron armor were carried out in Europe, where the iron and steel industry was most developed. Multilayer iron protection was tested with a wood spacer and it was found that in any case solid iron plates gave better protection per unit weight.

During civil war, most of American ships had multi-layer protection, which was caused more by the lack of industrial capacity for the production of thick iron plates than by the advantages of this type of protection.

Since the process of penetrating armor with a projectile is quite complex, extremely contradictory requirements are placed on armor. On the one hand, the armor must be very hard so that a projectile that hits it is destroyed upon impact. On the other hand, it is sufficiently viscous so as not to crack from impact and effectively absorb the energy of fragments resulting from the destruction of a projectile. Obviously, both of these requirements contradict each other. Most materials with high hardness have extremely low ductility.

With the development of armor production technology, a way to satisfy these conflicting requirements was quickly found. Armor began to be made in two layers - with hard outer surface and a plastic substrate that made up the bulk of the armor. In such armor, the hard outer layers break the projectile, and the viscous inner layers prevent fragments from passing into the ship.

At first it was proposed to line iron plates with cast iron or hardened iron, but these schemes showed the same decrease in reliability as wood-iron protection and did not surpass solid iron plates in strength. However, in 1863, the Englishman Cotchette proposed welding 25 mm steel plates to 75 mm wrought iron plates. Later, in 1867, Jacob Reese from Pittsburgh, pc. Pennsylvania, patented a cementitious compound which he claimed was suitable for cementing and strengthening armor plates. Efforts to implement these proposals were unsuccessful for many reasons, primarily due to the insufficient development of metallurgy. It will be recalled that the Bessemer process for making steel in a converter was developed between 1855 and 1860, and the Siemens-Martin process for making steel in an open furnace appeared in France and England a few years later. Each of these processes appeared in the United States several years after their introduction in Europe.

Cast iron was never used in the navy, but was used to armor ground fortifications, where the weight did not have such weight. of great importance. The most famous example of cast iron armor is the Gruson tower, which was constructed from large iron castings and was widely used to defend European borders. The first Gruson tower was tested in 1868 by the Prussian government.

Armor compound

The desire to obtain armor with a hard surface and a viscous substrate, and at the same time easy to process, led to the emergence of compound armor. First effective technology Its production was proposed by Wilson Cammel: a steel face obtained in an open furnace was poured onto the surface of a hot wrought iron slab. Also known is the Ellis-Brown compound plate, in which a steel face plate is soldered to an iron substrate with Bessemer steel. In both of these processes, developed in England, the slabs were rolled after soldering.

Over the next 10 years, the armor production process did not undergo any changes, with the exception of minor improvements in production technology, but the entire period was marked by intense competition and confrontation between all-steel and compound armor. All-steel armor was ordinary steel with a carbon content of 0.4-0.5%, while the steel surface of compound armor had 0.5-0.6% carbon. These two types of armor, whose relative strength depended largely on the quality of workmanship, were approximately 25% stronger than wrought iron armor, i.e. A 10-inch all-steel or compound slab would withstand the same impact loads as a 12.5-inch wrought iron slab.

Steel armor

By 1876, the power of artillery had increased so much that 560 mm armor was required to protect against the most powerful guns. But this year, tests were carried out in La Spezia that revolutionized the production of armor and made it possible to significantly reduce its thickness. In these tests, a 560 mm mild steel plate produced by the famous French company Schneider and Co. significantly surpassed all other tested samples. It was known that the steel contained 0.45% carbon and was obtained from a billet about 2 m high by forging it to the required thickness. The steel production process was kept secret.

These steel plates, while exhibiting excellent ballistic strength, were difficult to machine, and this difficulty led to further developments aimed at combining the stiffness of the steel plate with the toughness of the iron substrate. The steel used in these slabs was produced in Siemens-Maren open furnaces.

Nickel armor

The next step was to alloy the steel with nickel.

Nickel has the ability to greatly increase the toughness of steel. Under the same impact loads, armor plates made of nickel steel do not crack or peel off in fragments, as happens with pure carbon steel. In addition, nickel facilitates heat treatment - when hardening, nickel steel warps less.

In 1889, Schneider was the first to introduce nickel into all-steel armor, after which compound armor began to gradually fall out of use. The amount of nickel in the first samples varied from 2 to 5%, but eventually settled at 4%. At the same time, Schneider successfully applied the hardening of steel with water and oil. After hammer forging and normalization, the plate was heated to the hardening temperature, after which its front part was immersed to a shallow depth in oil. Quenching was followed by low-temperature tempering.

These innovations led to an improvement in armor strength by another 5%. Now 10 inches of nickel steel armor was equivalent to about a 13-inch plate of iron.

By this time, the American company Bethlehem Iron, under the leadership of John Fritz, began producing armor, and soon after that, the Carnegie Steel company under Schneider's patents. The first steel supplies for the old ironclads Texas, Maine, Oregon and other ships of this period consisted of heat-treated nickel steel with 0.2% carbon, 0.75% manganese, 0.025% phosphorus and sulfur and 3.25% nickel.

Harvey's armor

In 1890, the next major improvement in armor quality occurred with the introduction of the Harvey process, first used at the Washington Navy Yard to process 10.5-inch steel plates.

It is known that the hardness of iron-carbon alloys increases with increasing carbon content. So, cast iron is much harder than steel, which in turn is much harder than pure iron. This means that to obtain a solid front surface of the armor, it is enough to increase the carbon content in its surface layer.

The process invented by the American G. Harvey was as follows. A steel plate in close contact with some carbon-containing substance (for example, charcoal) was heated to a temperature close to the melting point and maintained in this state for two to three weeks. As a result, the carbon content in the surface layer increased to 1.0–1.1%, and at a depth of 25 mm remained at a level characteristic of ordinary steel.

The slab was then hardened through its entire thickness, first in oil and then in water, resulting in a super-hard cemented surface.

This process is called cementation (carburization). In 1887, Tressider patented in England a method for improving the hardening of a heated plate surface by applying fine water spray to it under high pressure. This method turned out to be better than immersion in liquid because it provided reliable access cold water to the surface of the metal, whereas when immersed, a layer of vapor appeared between the liquid and the metal, which worsened heat transfer. Steel with a hardened surface, alloyed with nickel, Harvey cemented, tempered in oil and hardened by water spray is called Harvey armor. Chemical analysis of typical Harvey armor from this period shows carbon content of about 0.2%, manganese - about 0.6%, nickel - from 3.25 to 3.5%.

Shortly after the introduction of the Harvey process, it was discovered that the ballistic strength of armor could be improved by reforging after cementation. Forging, which reduced the thickness of the plate by 10–15%, was carried out at low temperatures. It was originally used to more accurately maintain the thickness of the slab, improve the surface finish and structure of the metal after heat treatment. This method was patented by Corey of Carnegie Steel under the name “double forging.”

Harvey armor instantly proved its superiority over other types of armor. The improvement was 15–20%, meaning 13 inches of Harvey armor roughly corresponded to 15.5 inches of nickel steel armor.

Cemented Krupp armor

In the 80s of the 19th century. In metallurgy, another alloying additive, chromium, began to be used to alloy small steel castings. It turned out that the resulting alloy, with appropriate heat treatment, obtains significant hardness. However, steelmakers, despite constant efforts, were unable to obtain large ingots of chromium-nickel steel and process them accordingly, until the German industrialist Krupp solved this problem in 1893.

Krupp also introduced the cementation process into armor production, but instead of the solid hydrocarbons used in the Harvey process, he used gaseous hydrocarbons - illuminating gas was passed over the hot surface of the plate. Such gas cementation was often used, but it was gradually replaced by the use of solid hydrocarbons. Gas carburizing was used in Bethlehem in 1898, but after that it was not used in America for the production of armor.

Around this time, Krupp developed a process for deepening the cemented layer on one side of a steel plate. To do this, the slab was enveloped in clay, with the cemented side remaining open, and then the open side was subjected to strong and rapid heating. As the temperature drops from the surface into the slab, the surface is hotter than the back of the slab, allowing for "fall hardening" by splashing water. Steel heated above a certain temperature becomes very hard when quickly cooled with water, while steel whose temperature is below the specified limit practically does not change its properties when quenched. For convenience, we call this temperature critical. If the surface of the slab is heated above this critical temperature, then there is a level inside the slab where the metal is at a critical temperature, and this level gradually moves deeper into the slab and will eventually reach its back surface if the heating is prolonged enough.

However, the steel is heated in such a way that the critical temperature level does not fall deeper than 30-40% of its thickness. When such heating was achieved, the plate was quickly pulled out of the furnace, placed in the hardening chamber and powerful jets of water were applied first to the heated surface, and then, a second later, to both surfaces simultaneously. This double-sided irrigation was necessary to prevent deformation of the slab due to uneven cooling.

This process, called "fall-down surface hardening," made it possible to obtain a very strong face of the slab, constituting 30-40% of its thickness, while the remaining 60-70% of the slab volume remained in its original viscous state. It should be noted that this method of densification is based on incident heating and does not necessarily involve a change in the carbon content of the steel. In other words, in this hardening method, the face becomes super hard due to the more high temperature at the time of hardening, and the depth of the hardened layer can be adjusted by changing the heating mode and can be greater, if necessary, than the depth of carburization.

The face hardening process was, of course, a slab finishing process that was applied after the heat treating process. The latter improved the grain size of the material and created fibers that increased the strength and ductility of the steel.

The success of the Krupp process was immediate, and soon all armor manufacturers adopted it. On all plates thicker than 127 mm, Krupp armor was approximately 15% more effective than its predecessor, Harvey armor. 11.9 inches of Krupp steel was roughly equivalent to 13 inches of Harvey steel. In America, Krupp steel began to be used for armoring ships from 1900. Most of the armor made in the next 25 years was Krupp cemented armor.

Over the next 15 years, some improvements were introduced in production technology, and now Krupp armor is about 10% stronger than its first samples.

First year of the Great Patriotic War turned out to be difficult both for the country as a whole and for the defense industry in particular. The changing situation at the front made adjustments to the plans for development and launch in mass production even quite viable examples of individual protection for Red Army soldiers - many projects were closed simply because the leadership “didn’t have time for them.” Downside The medals were based on initiative developments from below, attempts to familiarize ourselves with imported samples. As a result, by the summer of 1942, it was possible to create the CH-42 bib, which received excellent reviews from the front based on test results.
Work in the second half of 1941

Based on the results of tests at the small arms research site in Shchurovo, it would seem that effective remedy protecting the fighter from bullets and shrapnel - steel breastplate CH-40A. Gross production was about to begin, but everything turned out to be not so simple. Whether the CH-40A ultimately ended up in service with the troops has not been documented.

On August 22, 1941, at the end of the field tests, 200 CH-40A “light” and “heavy” types were sent to the Western Front, where the front commander, Marshal of the USSR S. K. Timoshenko, got acquainted with them. He did not like the significant weight of the bibs (from 5.5 to 9.3 kg). On August 23, on behalf of Tymoshenko, the head of the artillery supply of the Western Front, Major General of the Quartermaster Service A.S. Volkov, wrote a letter with the following resolution: “...Steel breastplates cannot be used by a fighter who is already overloaded. The Marshal considers it advisable to make a marching embrasure instead of a breastplate, from behind which a fighter could fire.” Apparently, Marshal Timoshenko was not aware of the work of the previous few years...

Since Moscow was in the rear of the Western Front with a large number of factories, including metalworking ones, an experimental embrasure was made at ZiS (Stalin Plant) and showed it to Timoshenko, after which he personally made adjustments to the design of the shield. On September 6, 1941, the marshal demanded that a batch of 20 pieces be urgently produced and sent for testing to the military council of the Western Front. It is not known whether these products received any index, but the ZIS and Serp and Molot factories produced two batches of “embrasures designed by Timoshenko” with a total of 25 pieces. Both series did not withstand factory shelling tests and were safely forgotten.

The difficult situation at the front, encirclement, evacuation of factories and the general confusion of 1941 stopped work on means of protecting soldiers at the level of main departments, but now, without orders or instructions, work was carried out locally.

Thus, Tymoshenko’s activities served as the impetus for the start of proactive work at the Ordzhonikidze plant in Podolsk and at the Stalin Moscow Institute of Steel (later the Moscow Institute of Steel and Alloys, also known as MIS or MISiS). The Institute of Steel carried out developments based on one of the bibs, a sample of which was received from the People's Commissariat ferrous metallurgy, the remaining designs were unique and developed independently.

On December 7, 1941, a project for an armor shield for a single fighter developed by the Ordzhonikidze plant was presented. According to the factory's calculations, it was supposed to withstand being hit by a simple rifle bullet along the normal line from a distance of 175 m, and by a B-30 armor-piercing bullet from a distance of 100 at an angle of 45°. The shield was to be made from AB-2 steel with a thickness of 5 mm. The prototypes were made in two thicknesses, 4 mm and 5 mm - the first withstood a hit from a simple bullet from a distance of at least 300 meters, the second from a distance of 75 meters. Alas, the plant was soon evacuated, and the production of a pilot batch did not take place.

Armor shield designed by the plant named after. Ordzhonikidze, Podolsk (TsAMO). Click to view full size

Around the same time, military doctor 3rd rank Borovkov (unfortunately, the name and patronymic of the inventor have not been preserved) proposed a reflector shield of his own design for a rifle. The proposal was reviewed on December 6, 1941 by the Sanitary Department of the Red Army, and then sent to the combat training department of the spacecraft. There it was studied, and on January 20, 1942, the results were sent to the Main Artillery Directorate (GAU) of the Red Army. The following significant shortcomings of the reflector shield were identified:

Increases the weight of the rifle;
- creates inconvenience when carrying a rifle on a belt and especially behind the back;
- hinders the fighter’s actions in hand-to-hand combat.

However, for final conclusions, it was proposed to produce 300-500 prototypes and conduct tests at the front. On February 19, 1942, it was decided to produce a pilot batch of 500 units after some modification of the design. The reflector shield was produced by March 30 at LMZ in the amount of 100 pieces (the selection of steel and modification of the design was carried out by Research Institute No. 13), but further fate this proposal is unenviable. Borovkov's shields did not go into production; the characteristics and test results of this invention were not found in the archives.

Reflective shield for a rifle of the 3rd rank military doctor Borovkov system (TsAMO)

In addition, work was also carried out on a proactive basis in Leningrad at plant No. 189 of the People's Commissariat of the Shipbuilding Industry (NKSP). At the beginning of January 1942, an interesting design was introduced, which had straps, could be used as a shield and as a bib, and was carried behind the back in the stowed position.

The shield was tested at the artillery research site in Leningrad, which was notified to the command of the Leningrad Front. Unfortunately, the test report on this moment was not discovered, and further work appears to have been stopped.

Shield of plant No. 189 of the People's Commissariat of the shipbuilding industry, Leningrad (TsAMO)

The GAU did not rely only on domestic developments - for example, it studied the American experience, where personal protective equipment was actively used by the police. A vest was purchased and tested in the USA, which showed good protection against the German 9-mm MP-38/40 submachine gun, but mass purchases never took place.

Elliott Wisbrod vest (patent US2052684 A from the Patent and Trademark Office trademarks USA)

In the USA, work on the creation of means of protection against bullets was initially carried out in a different direction. Due to a different political system, the customers for the work could be either the state or private investors. At that time, the US Army did not think about war and did not carry out developments to protect soldiers, but the Great Depression and Prohibition gave rise to a surge in crime - shootings were not a rare occurrence on the streets of American cities. They were carried out mainly with pistols and revolvers, and later with the use of submachine guns, so the engineers were not faced with the task of protecting against rifle bullets. Products were developed that looked like ordinary clothing, but protected the wearer from a pistol or revolver bullet fired almost at point-blank range. They were used by police officers, gangsters and ordinary citizens. Representatives of the USSR purchasing commission saw an advertisement for one of these products in the newspaper.
Pre-production samples of the steel bib CH-42

On February 2, 1942, all developments on shields and breastplates were officially transferred to Research Institute No. 13 of the People's Commissariat of Armaments as an organization that by that time had extensive experience in the development and creation of means of protecting soldiers. However, under a separate agreement with the Artillery Committee of the GAU KA, work on the breastplates was continued by the Moscow Institute of Steel.

Since, according to the GAU, “one of the main types of small arms of all branches of the military is the submachine gun,” work was carried out to create steel breastplates with insignificant thickness and weight that protect the soldier from German submachine gun bullets at all distances. At the same time, the construction of steel embrasures was underway to protect the fighter from rifle bullets.

On February 9, the chairman of the technical council of the People's Commissariat of Armaments, E. A. Satel, received a letter signed by the deputy chief and military commissar of the GAU Artillery Committee, which indicated that the committee does not object to the production for testing at the front of a series of shields-armors that protect against bullets, fired from a German machine gun, and embrasure shields.

By March 3, 1942, at LMZ, on the basis of a letter from the GAU dated 02/13/1942 and an order from the Deputy People's Commissar of Ferrous Metallurgy V.S. Bychkov dated 02/18/1942, with the direct participation of representatives of Research Institute No. 13, steel breastplates (330 pieces) and bib guards (25 pieces).

The breastplates, which received the index CH-42, were produced only in the 2nd height, with a thickness of 2±0.2 mm from silicon-manganese-nickel helmet steel 36SGNA (factory index I-1). It is important to note that these breastplates of the March 1942 model have some design differences from the later, “classic” CH-42 version. They were a modification of the CH-40A with reduced thickness, modified taking into account the wishes received after tests in August 1941. The most noticeable difference was the introduction of a second vertical shoulder strap, inspired by the CH-38 breastplate. The total weight of the bibs in the batch ranged from 3.2 to 3.6 kg, with an average weight of 3.4 kg.

Acceptance of finished products was carried out in two stages; first, individual acceptance tests were carried out, and then control and verification tests. During the first stage, each part was individually fired with a cartridge with a reduced charge from a rifle of the 1891/1930 model from a distance of 25 meters, while the rear strength limit (RPT) was set at 400-410 m/s.

The following were subjected to individual acceptance tests:
chest part - 336 pieces, 331 passed the tests, or 98.5%;
abdominal part - 345 pieces, 339, or 98%, passed the tests.

The parts that passed the tests were painted and assembled into finished bibs, and then five were selected from them for the second stage of testing. At the second stage, the breastplates were fired from PPD-40 with live ammunition at normal range from a distance of 25 meters. The shelling was carried out in short bursts of 5-10 shots, the breastplates were attached to a wooden dummy. The number of hits in each breastplate ranged from 5 to 12. The breastplates withstood 70% of the hits without any damage to the back strength of the metal, the remaining 30% had “gray hair” and small cracks. There were no holes.

The first batch of bibs was made according to the drawing of the first version dated February 28, 1942. A little later, without an order from the GAU, the second batch of CH-42 (about 160 pieces) was produced according to the drawing of the second version dated March 23, 1942, which had a slightly modified design: a different shape of the abdominal part, changed attachment points for the “under-chest device” (lining between the body and steel of the bib at the top), a slightly different carabiner for hooking the second vertical strap.
Steel shield-bib SCHN-42

The embrasure shields mentioned in the letter of the GAU art committee on February 9, 1942 received the index SShchN-42 - a steel breastplate of 1942, by analogy with the 1939 breastplate SNSCH-39. During development, SNShch-39 was also taken as a basis, but with some changes:

The upper side is bent more;
- there are teeth on the bottom edge;
- the loophole has been redesigned: the cutout for the rifle is made at an angle of approximately 45°;
- the leg-stand is attached at one point, the lower supports of the stand are already adjusted;
- an additional waist strap has been introduced.

The shield was supposed to protect the fighter, both running and shooting while lying down, from rifle and machine gun bullets at all distances, and should not interfere with getting cartridges from the cartridge belt located on the fighter’s belt. SShchN-42 was manufactured at LMZ simultaneously with the first batch of SN-42, from the same steel 36 SGNA (I-1) with a thickness of 4.9 ± 0.6 mm. The assembled weight was 5.3 kg. The tests also took place in two stages.

Steel shield-breastplate SSHN-42 (TsAMO)

In the factory shooting range, from a distance of 25 meters from a rifle of the 1891/1930 model with a cartridge with a reduced charge, 27 SShchN-42 bibs were subjected to individual acceptance tests. The average speed of the bullet when hitting the shield was 782.8 m/s. 26 shields withstood the first stage without tears or cracks, after which painting and final assembly were carried out.

The second stage (control tests) was carried out in the form of shelling in a factory shooting range from a distance of 25 meters from German rifle captured live ammunition, the average bullet speed on impact was 768 m/s. For testing, two shields were selected, and six shots were fired at them along the normal line - both shields withstood all hits without any damage to the rear strength.
Testing the first CH-42s in combat

At the beginning of April 1942, the first batch of CH-42s were sent from Lysva to the 5th Department of the GAU Artillery Committee, where they underwent additional tests for bullet resistance and TTT compliance. The final verdict was as follows: “They protect the fighter’s chest from bullets fired from a German submachine gun at all distances.”

On May 16, 1942, 300 CH-42s, which remained intact after all the tests, were sent to the chief of artillery supply of the Western Front for testing in the field army. In case of a positive test result, the CH-42 bibs were supposed to be put into full production. Unfortunately, to this day no documents have been found on the tests of SShchN-42 - the only mention of them has been preserved in the correspondence of the GAU Artillery Committee: “... are on the way. Once they are received, they will also be sent to the active army for testing.” After this, traces of SCHN-42 are lost.

The bibs that arrived at the front were sent to the 5th Army, from where they received rave reviews in early June 1942. Thus, in a letter from the army command sent to the chairman of the technical council of the People's Commissariat of Armament of the USSR Latsis (name and patronymic unknown) and the chairman of the Artillery Committee of the GAU KA, Major General V.I. Khokhlov, contained a request: “For wider testing in combat conditions and obtaining comprehensive practical application, the military council of the 5th Army of the Western Front asks for the urgent production and dispatch of 35,000 pieces of armored breastplates to the 5th Army.”

Breastplate CH-42 from the first batch, found in the battle zone of the 5th Army of the Western Front. A bullet mark obtained during testing is visible in the center of the bib

Feedback from the 5th Army headquarters on the tests of the CH-42 stated:

"1. Armored breastplates provide reliable protection for a fighter from fire from German machine guns (submachine guns) from any distance, and also protect against fragments of mines and grenades.
2. The maneuverability of the fighters is almost not reduced; the armored breastplate does not prevent crawling and gives full opportunity to fire at the enemy both standing, kneeling and prone.
3. The armored breastplate, in addition to armor protection of the chest and abdominal cavity from enemy fire, increases the confidence of a fighter when performing combat missions.
Based on the above, the Military Council of the 5th Army considers it expedient to use armored breastplates in the Army in mass quantities... In the overall production of armored breastplates, it is necessary to eliminate a number of shortcomings...”

The shortcomings of the first CH-42, according to the command of the 5th Army, were as follows:

"1. To eliminate noise from the impact of the upper and lower panels, apply trim to the edge of the lower panel.

2. Set several sizes of armored breastplates depending on the height of the fighters.

3. When a bullet hits the top shield, the carbine mounting eye sometimes flies off, so instead of the eye, you should make a slot in the shield.

4. Make the wire for attaching the upper and lower shields stronger and larger in diameter.

5. With several impacts from a bullet, the rivets become loose, so they should be secured more firmly.”

On an initiative basis, the leadership of LMZ, without relying on the State Autonomous Institution, decided to independently test its products at the front - apparently, the negative experience of such tests had an impact previous years. To avoid incurring the wrath of the military, party resources were used. At the end of April 1942, a delegation of party workers from the Molotov region, on whose territory the Lysvensky plant was located, went to the 34th Army of the North-Western Front.

Breastplate CH-42, found by searchers S. Ivanov and S. Katkov in the battle zone of the 171st Infantry Division of the 34th Army

SN-42 bib of the second batch, captured from soldiers of the 171st Infantry Division. In the photo, an unterscharführer (non-commissioned officer) of the SS division “Totenkopf” next to a captured spacecraft soldier in uniform before the introduction of shoulder straps. A German's belonging to the SS is indicated by a belt buckle, and to the Death's Head division by buttonholes on the collar. This combination of uniforms and items of equipment makes it possible to unambiguously date the place and time of the photograph - the photo was taken in the spring-summer of 1942 in the Demyansk Cauldron (http://waralbum.ru)

The 34th Army of the NWF was not chosen by chance: it included a large number of units formed or replenished from residents of the Perm region, and the delegation was sent for patronage purposes. To one of the sponsored units, 171st rifle division, 160 CH-42 bibs were transferred to the second batch, which were involved in the May offensive on the positions of the battle group "Simon" of the SS division "Totenkopf".

The breastplates were used by scouts of the 171st SD, who described the positive and negative aspects of the breastplates. Subsequently, these descriptions were included in the report to the command of the army, and then the front. The response from the NWF command was sent on June 3, 1942 to the GAU and to the secretary of the Molotov Regional Committee of the All-Union Communist Party of Bolsheviks, from where it went to Lysva. In general, it is similar to the report of the headquarters of the 5th Army, written a little later:

"1. Bullet and shrapnel hits make minor dents, and the maneuverability of the fighters is almost not reduced, and they also do not interfere with crawling.

2. Breastplates turned out to be very useful when blocking bunkers and during attacks; they protect against machine gun fire, fragments of mines and shells.

3. They provide full opportunity to fire at the enemy from hand weapons, both standing, kneeling or prone...

According to the fighters and commanders of the reconnaissance group who used breastplates in battle, they are valuable and necessary, even in an offensive battle they are not a tedious type of equipment...

The scouts believe that the main disadvantage is that moving and crawling produces noise from the impact of the upper and lower shields, as well as from the impact of the bib on local objects; Thus, the scouts reveal themselves. Except this negative side, a breastplate for short fighters when crawling creates some inconvenience, resting on the hips, thereby interfering with normal movement and appropriate maneuverability ... "

The lower part of the CH-42 breastplate, found by S. Ivanov and S. Katkov in the battle zone of the 34th Army. Judging by the damage, the breastplate received a direct hit from a mortar shell.

In addition, protective characteristics were noted, which are interesting because they provide evidence and descriptions of direct participants in the battles:

“...During the reconnaissance process, three soldiers wearing breastplates had dents from direct hits, but the people were not out of action. According to the commander of this reconnaissance group, the enemy fired from a distance of 250-300 meters, and yet there were no through holes.

One of the fighters had a dent in his shield from a bullet about 3 mm deep on the right side of the upper shield at the level of his heart. The second fighter had a similar dent in the lower shield at the level of the abdominal cavity. According to all data, the scouts who were wearing breastplates were, in the above cases, protected from severe or even fatal injury.”

Specially noted tactical technique using a breastplate that was used in battle:

“...As a characteristic fact, I consider it necessary to point out that some reconnaissance officers, during the period when they were being shelled by machine-gun fire from the enemy, loosened the straps for fastening, and used the breastplate itself as shields, placing them somewhat in front of them, in the direction from which the enemy’s machine-gun fire was coming.” .

At the end of the report, there was information about the duration of the test - “about three weeks, and are currently in action” - and a succinct response from the fighting soldiers: “... the soldiers are very grateful to the gift of the Molotov delegation.”

It would seem that after such reviews from the active army, the bib should have been put into general production, and it would have taken its place among the equipment of the Red Army soldiers as having proven its effectiveness... But the bib produced by the Lysvensky Metallurgical Plant had worthy competitors, and the GAU Artillery Committee decided to carry out comparative tests, which will be discussed in the next article.

Armor is a protective material characterized by high stability and resistance to external factors that threaten deformation and violation of its integrity. It doesn’t matter what kind of protection we are talking about: be it knightly armor or the heavy coating of modern combat vehicles, the goal remains the same - to protect from damage and take the brunt of the blow.

Homogeneous armor is a protective homogeneous layer of material that has increased strength and has the entire section has a homogeneous chemical composition and identical properties. It is this type of protection that will be discussed in the article.

History of the armor

The first mentions of armor are found in medieval sources, we're talking about about the armor and shields of warriors. Their main purpose was to protect body parts from swords, sabers, axes, spears, arrows and other weapons.

With the advent firearms there was a need to abandon the use of relatively soft materials in the manufacture of armor and move to more durable and resistant not only to deformation, but also to conditions environment alloys

Over time, decorations used on shields and armor, symbolizing the status and honor of the nobility, began to become a thing of the past. The shape of armor and shields began to be simplified, giving way to practicality.

In fact, all world progress has come down to a race of invention speeds newest types weapons and protection from them. As a result, simplifying the shape of the armor led to lower cost (due to the lack of decoration), but increased practicality. As a result, armor became more affordable.

Iron and steel found further use when the quality and thickness of armor became paramount. The phenomenon found a response in shipbuilding and mechanical engineering, as well as in strengthening ground structures and sedentary combat units such as catapults and ballistas.

Types of armor

With the development of metallurgy in historical terms, improvements in the thickness of shells were observed, which gradually led to the emergence of modern types of armor (tank, ship, aircraft, etc.).

IN modern world The arms race does not stop for a minute, which leads to the emergence of new types of protection as a means of countering existing types of weapons.

Based on the design features, the following are distinguished:

homogeneous;
reinforced;
mounted;
spaced out.

Based on application methods:

body armor - any armor worn to protect the body, and it does not matter whether it is the armor of a medieval warrior or the body armor of a modern soldier;
transport - metal alloys in the form of plates, as well as bulletproof glass, the purpose of which is to protect the crew and passengers of the equipment;
ship - armor for protecting ships (underwater and surface);
construction - a type used to protect pillboxes, dugouts and wood-earth firing points (bunkers);
space - all kinds of shockproof screens and mirrors for protection space stations from orbital debris and the harmful effects of direct sunlight in outer space;
cable - designed to protect submarine cables from damage and durable operation in aggressive environments.

Armor homogeneous and heterogeneous

The materials used to make armor reflect the development of outstanding design ideas of engineers. The availability of minerals such as chromium, molybdenum or tungsten allows the development of high-strength samples; the absence of such creates the need to develop narrowly targeted formations. For example, armor plates that could easily be balanced in terms of price and quality ratio.

According to its purpose, armor is divided into bulletproof, projectile-proof and structural. Armor, whether homogeneous (made of the same material over the entire cross-sectional area) or heterogeneous (varies in composition), is used to create both bulletproof and projectile-proof coatings. But that's not all.

Homogeneous armor has both the same chemical composition over the entire cross-sectional area and identical chemical and mechanical properties. Heterogeneous steel can have different mechanical properties (steel hardened on one side, for example).

Rolled homogeneous armor

According to the manufacturing method, armor coatings (whether homogeneous or heterogeneous armor) are divided into:

Rolled. This is a type of cast armor that has been processed on a rolling machine. Due to compression on the press, the molecules move closer to each other, and the material is compacted. This type Heavy-duty armor has one drawback: it cannot be cast. Used on tanks, but only in the form of smooth plates. On a tank turret, for example, a rounded one is required.
Cast. Accordingly, less durable in percentage terms than the previous option. However, such a coating can be used for tank turrets. Cast homogeneous armor will, of course, be stronger than heterogeneous armor. But, as they say, a spoon is good for dinner.

Purpose

If we consider bulletproof protection against conventional and armor-piercing bullets, as well as the impact of fragments of small bombs and shells, then such a surface can be presented in two versions: rolled homogeneous armor of high strength or heterogeneous cemented armor with high strength on both the front and back sides.

Anti-ballistic (protects against the impact of large projectiles) coating is also available in several types. The most common of them are rolled and cast homogeneous armor of several strength categories: high, medium and low.

Another type is rolled heterogeneous. It is a cemented coating with hardening on one side, the strength of which decreases with depth.

The thickness of the armor in relation to hardness in this case is a ratio of 25:15:60 (outer, inner, back layers, respectively).

Application

Russian tanks, like ships, are currently covered with chromium-nickel or nickel-plated steel. Moreover, if during the construction of ships a steel armor belt with isothermal hardening is used, then the tanks are covered with a composite protective shell, which consists of several layers of materials.

For example, the frontal armor of the Armata universal combat platform is represented by a composite layer, impenetrable to modern anti-tank projectiles of up to 150 mm caliber and sub-caliber arrow-shaped projectiles of up to 120 mm caliber.

Anti-cumulative screens are also used. Hard to say, best armor it is or not. Russian tanks are improving, and with them the protection is improving.

Armor vs Projectile

Of course, it is unlikely that members of the tank crew keep detailed performance characteristics combat vehicle, indicating how thick the protective layer is and what kind of projectile it will hold at what millimeter, as well as whether the armor of the combat vehicle they are using is homogeneous or not.

The properties of modern armor cannot be described by the concept of “thickness” alone. For the simple reason that the threat from modern projectiles, against which, in fact, such a protective shell was developed, comes from the kinetic and chemical energy of the projectiles.

Kinetic energy

By kinetic energy (it would be better to say “kinetic threat”) we mean the ability of a projectile blank to penetrate armor. For example, a projectile from or will pierce right through it. Homogeneous steel armor is useless against such hits. There are no criteria by which it can be stated that 200 mm homogeneous is equivalent to 1300 mm heterogeneous.

The secret to countering a projectile lies in the location of the armor, which leads to a change in the vector of the projectile’s impact on the thickness of the coating.

HEAT projectile

The chemical threat is represented by such types of shells as anti-tank armor-piercing high-explosive (according to the international nomenclature designated as HESH) and cumulative (HEAT).

HEAT projectile (contrary to established opinion and influence Games World Of Tanks) does not contain a flammable filling. Its action is based on focusing the impact energy into a thin stream, which, thanks to high blood pressure, and not temperature, breaks through the protective layer.

Protection against this kind of projectiles is the build-up of so-called false armor, which absorbs the energy of the impact. The simplest example is the covering of tanks with chain-link mesh from old beds during World War II by Soviet soldiers.

The Israelis protect the hulls of their Merkavas by attaching steel balls to the hulls, hanging from chains.

Another option is to create reactive armor. When a directed jet from a cumulative projectile collides with a protective shell, detonation of the armor coating occurs. An explosion directed in counterweight leads to the dispersion of the latter.

Land mine

The action comes down to flowing around the armor body during a collision and transmitting a huge impact impulse through the metal layer. Further, like pins in a bowling alley, the layers of armor push each other, which leads to deformation. Thus, the armor plates are destroyed. Moreover, the layer of armor, when scattered, causes injury to the crew.

Protection against high-explosive shells can be the same as against cumulative shells.

Conclusion

One of the historically recorded cases of the use of unusual chemical compositions To protect the tank, there is a German initiative to cover the equipment with Zimmerit. This was done to protect the hulls of the Tigers and Panthers from magnetic mines.

The zimmerit mixture included elements such as zinc sulfide, sawdust, ocher pigment and a polyvinyl acetate-based binder.

The use of the mixture began in 1943 and ended in 1944 for the reason that drying required several days, and Germany at that time was already in the position of the losing side.

In the future, the practice of using such a mixture did not find a response anywhere due to the refusal of infantry to use hand-held anti-tank magnetic mines and the emergence of much more powerful types of weapons - anti-tank grenade launchers.

The problem of protecting fighters from bullets and shrapnel has existed since the advent of firearms. The Red Army began to pay attention to this problem from the beginning of the 30s, simultaneously with the beginning of the development of the domestic steel helmet.

There were two main areas of research work to create protection: determining the optimal shape of a helmet, as light and technologically advanced as possible, and searching for steel capable of combining good bullet resistance and ductility. The resulting material was supposed to be used not only for helmets, but also for various types of protective shells and armored shields. By the end of 1935, the necessary alloy was found, the hardening technology was developed, and in November the first samples of a steel helmet, designated SSh-36, were born.

First of all, the task was to provide the army with steel helmets, the production of which was difficult, and production was far behind schedule. The shortcomings of steel and production technology were revealed, work was carried out to improve the shape of the helmet, experimental models of helmets and new alloys appeared and were tested. There was practically no work on developing protection for the bodies of soldiers. Nevertheless, various institutions of the USSR received letters from inventors with proposals for all kinds of protective devices: shields, bibs, etc. Ultimately, these letters ended up in the Department of Cargo Supply (UOVS) of the Red Army or the People's Commissariat of Defense (NKO) of the USSR. Among them were proposals that were implemented in metal and tested, but not adopted for service: protection of hands and face, attached to a rifle, armored plate, worn in the breast pocket of a tunic and called the “heart of steel,” etc.

First experiments. Engineer Weinblatt's Armor Chest

The project of the head of the bureau deserves the most attention technical specifications Design Bureau No. 2 of the Izhora Plant (Kolpino) by engineer I.M. Weinblat, drawn up by him in the form of an explanatory note and drawing and sent to the invention department of the NPO on April 16, 1937. This project is noteworthy in that it attracted the attention of NGO management to the problem of individual protection of fighters and gave impetus to further work in this direction.

Weinblat proposed an “Armored Breastplate” for protection against a 7.62 mm rifle bullet (though without specifying what type), consisting of two parts. The breastplate itself was supposed to protect the entire chest and shoulders from bullets, as well as bayonet and saber strikes. The belly protection was supposed to be attached to it from below with straps. The breastplate was intended for assault troops, motorized infantry and cavalry.

“Armored breastplate” by engineer I. M. Weinblat (RGVA)

Two versions of the breastplate were offered - with 2-mm and 3-mm thick plates made of IZ-2 armor steel. Weinblat gave a calculation of bullet resistance: for the 2-mm version, protection was provided against being hit by a normal bullet at a distance of 850 m, 3-mm plates withstood hits at a distance of 350–400 meters. In addition, the breastplate protected against bayonet and saber strikes. For the 3-mm version, a theoretical weight calculation was made: upper part (chest protection) - 3.21 kg, lower part (abdomen protection) - 1.62 kg.

Weinblat supported his project with the conclusion of the military representative of the ABTU at the Izhora plant, military engineer of the 3rd rank B.A. Debinsky, dated April 15, 1937, which noted the value of the proposal and proposed testing the prototype by shelling. The letter was reviewed in the invention department of the NPO, and on May 14, a response was sent from there about the need to manufacture prototypes of both versions of the bib and test them at the test site. To ensure this work was carried out, the senior military representative of the Main Artillery Directorate (GAU) at the Izhora plant, a certain Lakida, was involved.

In turn, Lakida gave his opinion on June 1 “the speedy production of test samples, on which it is necessary to study the convenience of the design and the thickness of the armor”. As a result, by September 13, 1937, equipment for production and the first samples of breastplates made of 3 mm armor were made. The delay was explained by a change in the management of a number of workshops (there was a wave of arrests at the plant).

Plates were cut from armor plate blanks and were subjected to shelling at the training ground, on the basis of which a conclusion was made about the bullet resistance of the breastplates. The manufactured samples differed from the originally proposed version: IZ-2 steel was replaced with cheaper FD-5654, and the belt system for fixing the bib on the body was changed. The armor after rolling and hardening was bulletproof “at the height of the requirements for armor adopted by ABTU”.

General form engineer I. M. Weinblat’s breastplate (left) and the breastplate when worn (right) (RGVA)

The shelling of the plates made of the breastplate material was carried out with a “simple three-line bullet” from distances of 400 m at an angle of 90 degrees, and from 350, 300 and 200 m at an angle of 30 degrees. The results of the shelling showed that there were no penetrations at a distance of 400 meters; when fired at an angle of 30 degrees, there were breaks at a distance of 200 meters - i.e., the initial calculations were confirmed. The weight of the actual chest protection sample turned out to be slightly greater than the calculated one (3.49 kg); the lower part to protect the abdomen was not made.

After the shelling of the plates, in early November 1937, the produced prototypes of the breastplate were transferred to the NKVD division under the command of the senior lieutenant of the Factory. Based on the results of the tests on November 13, 1937, the following conclusion was received:

1. At the right shoulder you need to make a cutout to fit the butt;
2. Change the belt fastening system;
3. Felt pads and springs to the back are required;
4. Practical use of the armor when worn and in various positions has shown that the chest is freed from the pressure of the fighter’s equipment belts - at least for winter conditions (under an overcoat). Conditions for wearing summer time subject to research. The shell's own weight does not burden the fighter much (for small marches).
5. It is advisable to check the shell after implementing changes in practical shooting.
6. It is advisable to study the issue of replacing belts in all places with flat springs.

Based on the results obtained, Weinblat made a conclusion about the need for a bib for the Red Army, proposed to launch it into general production after establishing a dimensional grid and approving technical specifications, and also carried out an approximate calculation of the required number of bibs produced (15,000–20,000 per month, 170,000–220 000 per year).

A report on these works was sent on December 27, 1937 to the 7th Main Directorate of the NKOP USSR, from where on January 15 the document was sent to the Red Army Military Directorate with a proposal to order an experimental batch of breastplates to the Izhora plant. On January 24, this was reported to the Deputy People's Commissar of Defense of the USSR, Marshal A.I. Egorov, with a request to authorize the order of an experimental batch of 1000 pieces, but the next day Egorov was removed from his post and appointed commander of the troops of the Transcaucasian Military District, and later arrested and executed.

For some time the question of breastplates was postponed, but not forgotten. At the UOVS, the drawings and the report were carefully studied, and on March 5, 1938, proposals for improving the bib were sent back to the 7th Directorate of the NKOP:

1. Shorten the shoulder pads by 4 centimeters;
2. Reduce the rear protrusions under the armholes of the bib by 3 centimeters;
3. Enlarge the cutout of the right shoulder for the rifle butt;
4. Grind the edges adjacent to the fighter’s body;
5. Bead the front part of the neck;
…
8. Consider it expedient to develop a special grade of steel that would maximally combine tough and hard properties and would minimize the harmful effects of the vortex effects of heated lead.

CH-38 - the first serial breastplate of the Red Army

They returned to Weinblatt's breastplate again in August 1938. The author of the project was summoned to the UOVS, where he presented a modified version of the bib (version dated June 27, 1938), but upon returning to the Izhora plant, Weinblat was arrested by the NKVD. The tragedy of the situation is that in October 1938 he was again summoned by telegram to the UOVS to submit his sample for approval by the People's Commissar of Defense Marshal Voroshilov, but the telegram was late, the summoned person was not found...

By that time, apparently, the manufacturing plant, the volume of the pilot batch and the timing of its submission for testing had already been previously agreed upon by all the People's Commissariats (NKTP, NKOP, NKO and UOVS). According to Weinblat, the Izhora plant was supposed to produce 1,000 breastplates by January 1, 1939, which were to be tested by the troops from January 1 to April 1 of the same year. This explains the events that followed.

Without waiting for decisions on bibs from the UOVS and NGOs, having informed Voroshilov in fact, on October 22, 1938, the People's Commissar of Heavy Industry L. M. Kaganovich gave instructions to develop and produce at LMZ (Lysvensky Metallurgical Plant - a new abbreviated name for the plant named after the newspaper "Industry" ) by January 1, 1939, a pilot batch of steel bibs: 250 pieces weighing 4–5 kg and 250 pieces of a lightweight type weighing 2–2.5 kg. Since LMZ worked on steel helmets in close cooperation with Research Institute No. 13, the same team of engineers from Research Institute No. 13 was involved in working on the breastplate.

Lysva, immediately upon receiving Kaganovich’s instructions, without waiting for the technical conditions and forms of the bib from the UOVS (formulated on the basis of Weinblat’s work), began work. Thus, by the time the UOVS representative arrived at LMZ, three of their own molds had already been developed, based on the samples of which the pilot batch was being manufactured. All these LMZ bibs received the index SN-38, although in fact they were products of different design. In addition to Kaganovich’s orders, on November 9, 1938, a letter from Voroshilov was received, which contained the tactical and technical requirements (TTT) for the bibs and approved the procedure for accepting the experimental batch. The TTT specified bullet resistance (the distance at which it is guaranteed not to penetrate) for each type of bib: 350 meters for a bib weighing 4–5 kg and 700 meters for a bib weighing 2–2.5 kg.

General view of the two-piece bib CH-38 (RGVA)

Engineer Weinblat was convicted and ended up in the “sharashka” - the Special Technical Bureau of the NKVD of the Leningrad Region. There he tried to resume work on his bib by writing a letter to the UOVS on June 9, 1939, but it was too late - the work was already being carried out by another plant and research institute.

January 5, 1939 acting Director of LMZ Zhukov reported in a memorandum to People's Commissars Kaganovich and Voroshilov that, with the participation of Research Institute No. 13, he completed the task of manufacturing a pilot batch of steel breastplates. A total of 491 bibs were made (according to other documents the figure is slightly higher, more on that below) of four types of two different designs. These were the first steel breastplates made in the USSR - albeit in a small batch, but in series. Of them:

1. Heavy type of three parts – 107 pcs.
2. Heavy type of two parts – 115 pcs.
3. Lightweight type of two parts – 260 pcs.
4. Light type of two parts – 9 pcs.

General view of the three-piece bib CH-38 (RGVA)

The material for the breastplates was a new silicon-manganese-nickel steel, which was also used in the experimental helmet SSh-38-2 - after minor changes it was accepted for supply to the Red Army under the designation SSh-39. The breastplates differed from each other not only in the number of parts and the thickness of the armor plates, but also in the under-body device (the lining between the body and the armor).

CH-38 of three parts were made only of the heavy type (breastplate thickness 3.5–3.6 mm), they were equipped with two types of under-body devices:

CH-38 were made from two parts three types: heavy (bib thickness 3.5–3.6 mm), lightweight (1.5–1.6 mm) and light (1.15–1.25 mm). They were equipped with seven types of subtool devices. In total, it is possible to distinguish as many as nine varieties of CH-38, differing in design, steel thickness and type of under-body device. It was not possible to find the exact number of bibs of each type produced in the documents.

Metal thickness, mm	Subtotal device type	Weight of the under-body device, kg	Bib weight, kg	Bullet resistance, m
3,5–3,6	Made of sponge rubber, covered with cotton fabric on both sides	0,510–0,555	6,0–6,2	350
3,5–3,6		0,270–0,310	5,6–5,8	350
1,5–1,6	Made of two layers of cotton fabric, with a sewn-in layer of sponge rubber at the collar	0,160	3,0–3,1	600–700
1,5–1,6	Made of two layers of cotton fabric, with a sewn-in layer of sponge rubber along the contour	0,270–0,310	3,1–3,2	600–700
1,5–1,6	Made of sponge rubber (in the chest area), lined on both sides with cotton fabric	0,410–0,440	3,3–3,4	600–700
1,5–1,6	Made of sponge rubber (solid), covered on both sides with cotton fabric	0,510–0,555	3,4–3,5	600–700
1,15–1,25	Cloth, with a sewn-in layer of sponge rubber at the collar	–	2,35–2,4	–

The “Act of shooting test of steel breastplates” dated December 29, 1938 allows us to find out interesting details: according to the tactical and technical requirements, all heavy and lightweight breastplates from the pilot batch were subject to individual shooting testing. For the heavy type, the distance was set at 350 meters, for the light type - 700 meters. The tests were carried out with cartridges with a reduced charge from a distance of 25 meters (due to the lack of LMZ’s own testing ground). The initial velocity of the bullet was 612.9 m/s for the heavy type bibs, 362.9 m/s for the light type, and 320 m/s for the light type.

SN-38 heavy type of three parts (left) and heavy type of two parts (right) (RGVA)

From this document it was possible to establish the exact number of issued CH-38 bibs of all types, since it indicates the total number of bibs presented for testing, as well as the number of those that passed the tests:

a) heavy type 289, of which 250, or 86%, passed the tests;
b) lightweight type 277, of which 251, or 90%, passed the tests;
c) light type 9, of which 9, or 100%, passed the test.

The need for control shooting of a small number of breastplates that passed the test with live ammunition was emphasized, which was done on January 2, 1939. The shelling was carried out from the distances specified in the requirements; in addition, additional testing was carried out from distances of 600, 500, 250 and 50 meters. 20 bibs of heavy and light types were tested.

Based on the results of the shelling, it was noted that the breastplates fully comply with the tactical and technical requirements: lightweight breastplates penetrate from a distance of 500 meters, heavy breastplates penetrate from a distance of 250 meters in 50% of cases. In addition, it was noted that a heavy type bib made of two parts can be used when folded as a shield and cannot be penetrated from a distance of 50 meters.

Two samples of lightweight two-piece SN-38 (RGVA)

The experimental batch of CH-38 was to be thoroughly tested and determined how to use the breastplates in the Red Army. By order of the head of the UOVS dated January 4, 1939, the bibs were to be sent for testing to the test site in Shchurovo; they were to be tested on:

a) bullet resistance and protection from lead splashes (formed when a bullet hits);
b) determining the impact force of a bullet and the impact of the impact on the chest and abdominal cavity;
c) combat socks.

According to the decision of the meeting of the Military Department of the NKTP on January 15, 1939, the tests should have been completed by February 5, leadership was entrusted to the UOVS of the Red Army. Among the departments involved in this process was the Sanitary Department (SU) of the Red Army. On January 17, 1939, the head of the UOVS asks the management of the SU to send an order to the chief Military Medical Academy on testing bibs on animals in order to “...identifying all possible cases of violation of the physiological properties of a living organism when struck by a bullet”.

In the second half of January, bibs of all types were familiarized with in Moscow, as a result of which clarified tactical and technical requirements appeared, approved on January 26 by the People's Commissar of Defense Marshal Voroshilov. They fixed the shape of the bib (of two parts) and the possibility of installing it and using it when folded as a shield.

SN-38 heavy type, made of three parts with a first-type under-body device, preserved in the collection of the helmet museum, Lysva

To test breastplates in tactical conditions and all types of combat, by order of the USSR NKO dated January 28, 1939, they were sent to the 1st Moscow Rifle Division and tested in the 1st Moscow rifle regiment them. Mikhailovsky (the bibs reached the regiment only on February 14).

Based on the results of the tests on February 21, a report was drawn up, which noted some inconvenience in the placement and use of pouches, a shovel and a gas mask simultaneously with the bib and assessed the influence of the bib on the fighter’s mobility, and also made a number of proposals for improving the design. Attached to the act was a request to extend the testing period until March 10. The tests were extended, and on March 17, 1939, an act was written based on the results of additional military tests, who stated:

running, crawling and skiing do not cause any difficulties;
fatigue on short runs is insignificant;
when marching over short distances (5, 7 and 12 km), fatigue is insignificant, according to the fighters - the breastplate balances the backpack;
when self-digging, the bib does not interfere;
does not interfere with throwing grenades from all positions;
does not interfere with preparation for shooting and shooting while lying down;
does not interfere with the use of a bayonet;
good protection during a bayonet attack.

Disadvantages were also noted:

when shooting from the knee, sitting or standing, the shoulder ridge is partially blocked, which interferes with the butt and aiming;
when moving, the breastplate rubs the fighter’s hips;
a tight fit causes sweating in the chest;
the horizontal strap clasp is inconvenient; the fighter cannot remove and put on the bib on his own.

The conclusions read:

it is necessary to make bibs of different sizes;
change the shoulder part - “make it cooler”;
make a larger cutout for the butt;
a steel breastplate will save many lives of soldiers, commanders and political workers in a future war.

Until August 1939, there was a break in work on steel breastplates. The CH-38 was not put into full production, but it became a serious step forward in the process of developing individual protection for Red Army soldiers on the battlefield.