Modern armies use polymer fiber composite helmets for protection against fragments. But there are metallic alternatives that have their own benefits and should not be forgotten. One of these materials is steel, which is trying to make a comeback.
Every ballistic helmet has its place in the protection equation. Polymer fiber composite helmets replaced steel in the 1980s, but steel has not vanished anywhere. Steel helmets just were not developed actively after World War II. Currently, composite helmets dominate the market single-handedly. Steel is trying to make a comeback in the United States, but it is not easy considering the overall attitude towards that material.
Steel is considered an outdated material that has no development potential. One could not be more wrong. Steel alloys are developing every day. Many do not know that ballistic helmets made from modern steel alloys weigh roughly the same as para-aramid (i.e. Kevlar) helmets. Steel offers roughly the same protection against fragments per weight basis, but superior protection against bullets.
Steel reigns in reducing contact injuries. Contact injuries are formed when the helmet’s ballistic shell bulges during projectile impact and touches the head. Energy transfer can be fatal when a composite helmet is hit by a bullet fired from a high-powered handgun. This problem is especially acute with modern mass-efficient ballistic materials, like Ultra High Molecular Weight Polyethylene (UHMWPE), which allows a very thin ballistic shell. The shell lacks rigidity.
A Brief History of 20th Century Steel Helmets
France was the first nation to adopt steel helmets for its troops during World War I in 1915. These Adrian helmets were 0,5 millimeters thick at first and made from Bessemer steel. Later the thickness of the ballistic shell was increased to 0,7 millimetres. Adrian helmets provided limited protection against fragments and blunt impact.
The British and Germans, among many other nations, quickly followed in the footsteps of France and developed their own steel helmets. The British issued a steel helmet designed by John Brodie in 1916. It was first made from mild steel but was replaced by Hadfield steel. Hadfield manganese steel was developed by Sir Robert Hadfield (1858-1940). It contains 13% manganese by weight and 1,2% carbon. Hadfield steel impact hardens, and its microstructure transforms from a soft state to a hard martensite. The tracks of modern main battle tanks are made from manganese steel. When exposed to nuclear explosions they become radioactive (induced radioactivity) and must be changed.
The Germans began work on their own ballistic steel helmet in late 1915, which would become the famous Stahlhelm. It was developed by a Prussian engineering professor Friedrich Schwerd of the Technical Institute of Hanover. Stahlhelms were issued to German troops in early 1916. Metallurgically, these helmets were made of a superior chromium-nickel alloy, were one millimeter thick, and were quenched and tempered to a martensitic microstructure and a hardness of 49-54 Rockwell C. During World War II the Germans had to replace chromium-nickel alloy with silicon-manganese due to strategic metal shortage. Ballistic properties remained the same. The German Stahlhelm was among the Russian SSh-40 helmet the best steel helmet of World War II.
Americans issued the British Brodie helmets for their troops in World War I. Americans made a copy of the British Brodie helmet called M1917 Kelly. Nearly three million American M1917 helmets were produced before the end of World War I. In 1941 the Americans replaced the Kelly helmet with the M1 steel helmet, which was made from Hadfield steel.
After World War II armies across the world used steel helmets until the 1980s during which polymer fiber composites started to replace steel. The biggest reason for steel’s downfall were the fact that they were not developed actively after World War II, as mentioned earlier. Steel and titanium have their own important palace in the protection equation of the head and cannot be removed or ignored.
Russian Special Steel
The last Russian steel helmet for ordinary troops was the SSh-68 helmet, which was quite surprisingly inferior ballistically to the SSh-40 steel helmet of World War II. After the 1972 Munich Summer Olympic terror attack there was a need for a helmet for the Special Operations Forces (SOF) that offered better ballistic protection than the current steel helmets. In Europe, titanium was selected as the new ballistic material.
A Swiss company called TIG Bicorg AG developed a titanium assault helmet called PSH-77 in the year 1977. TIG also had a West German subsidiary called Garant Schutztechnic GmbH. The Soviet Union acquired titanium helmets from the German company. Its home office was in Switzerland so all export sanctions could be outmanoeuvred.
Russians copied the PSH-77 and manufactured their own improved titanium version of it called the Altyn helmet. The metal forming technologies developed for the Altyn project were crucial in manufacturing steel assault helmets in the 1980s and 1990s. Russian NII Stali Institute manufactured the first Russian steel assault helmet by deep drawing/stamping in 1985 called the Vityaz-S.
In the 1990s a Russian company called NPP KLASS started to manufacture ballistic protection from steel and composite fiber. Their products were the well-known SSSh-94 Sfera-S and Maska-1 steel assault helmets. These were very heavy since the ballistic shell was 2,5 millimeters thick on both helmets. The protection they offered was good. Being able to stop even rifle ammunition fired from a reasonable distance striking almost perpendicularly.
There have been no new Russian steel helmets after the Sfera-S and Maska. Prototypes have been shown in arms exhibitions, but that is all. The Russians for some reason do not want to make rifle-resistant steel helmets by optimizing the protection using hybrid material solution. No one makes a rifle-resistant helmet entirely out of steel. That is madness. Thinner layers of modern steel alloys and a ceramic add-on plate to the forehead are the right way to go.
Comeback of Steel in the United States
Steel is trying to make a comeback in the United States in ballistic helmet applications. Behind all of this is a firm called Adept Armor. They have a product portfolio built around the high-tech NovaSteel metal alloy.
Adept’s NovaSteel products offer NIJ IIIA and VPAM 3-compliant armor protection. The NovaSteel helmet excels in reducing contact injuries due to low backface deformation. The NovaSteel breastplate is an excellent piece of kit i.e. riot control and it offers ballistic protection. This ballistic protection can be upgraded to rifle class using an add-on plate.
Being the first to market ballistic steel helmets for a long time is not easy. People have bad attitudes towards steel as a personal ballistic protection material. It is considered an outdated material. Nothing could be more from the truth. Advances in metallurgy and manufacturing are made every day.
When it comes to ballistic helmets made from different materials, steel makes sense. It minimizes head injuries, weights roughly the same as similar polymer fiber helmets, and has excellent multi-hit performance.
Adept Armor: Modern Steel Body Armor
Adept Armor (USA) is a leading developer of body armor and protective materials. They are a dedicated team of materials scientists, engineers, and designers specializing in cutting-edge, customizable body armor systems and personal protective gear. Adept has experience in both inorganic chemistry (particularly metal alloys and ceramic compounds) and organic biochemistry.
Adept Armor has modern steel body armor in their product portfolio. These include the NovaSteel helmet, breastplate, and buckler shield. They offer unique protective properties at a light weight that polymer fibers cannot offer, like extremely low backface deformation, excellent stab and multi-hit protection.
Austria and Russia Continue with Titanium
Austria has long traditions of manufacturing titanium ballistic protection helmets. The Austrian manufacturer Ulbricht’s has two titanium helmet options Zenturio and Optio. The former for rifle protection and the latter for handgun protection. Ulbricht’s helmets are one of the finest titanium helmets on the market. They are very well-liked in European police organizations.
Russia has abandoned steel as a material for personal ballistic protection. All new metallic helmets that have come to market recently are made from titanium. Kalashnikov Group has introduced two new titanium helmets, the Elbrus-T and Bars-L. Aluminum hybrid helmets have also a role to play in the Russian protection markets. They are used by police organizations like Rosgvardia.
The biggest reason titanium helmets are not in a very widespread use is their price. This is well understood, and development has been going on for many years to develop low-cost titanium alloys.
Russian has developed a low-cost titanium alloy called VST-2B that is manufactured from a low-grade titanium sponge. Still, they have managed to maintain the ballistic protection levels the same as with previous alloys. Ballistic protection products made from VST-2B alloy cost only half of previous generation products. This allows a more widespread deployment of titanium helmets to troops that are not at the top of the food chain.
It remains to be seen what happens to the comeback of steel in the United States and how the titanium industry manages to lower the price of titanium even further. One thing is sure, metallic helmets are not going anywhere. They have too many benefits and are here to stay.
This article incorporates historical steel helmet research conducted by Jake Ganor, CEO of Adept Armor.
Terminal Ballistics of Metals
Monolithic steel and titanium perform the same against handgun threats at equal areal weights. But steel is much better against fragments than titanium. Titanium is rarely used in monolithic form. Most practical solutions are hybrid structures. Which means that titanium has a polymer fiber composite support at its backface.
The protection of steel sheet/plate increases linearly with thickness against fragment simulating projectiles (FSP). Titanium on the other hand shows non-linear behaviour. This is due to titanium’s sensitivity to adiabatic shear. Titanium fares better in hybrid armor solutions as mentioned above. Stronger alloys can be used with a polymer fiber composite backing compared to monolithic titanium.
Aluminum is good at fragments due to its toughness. Strong armor aluminum alloys do show brittle exit mode when penetrated by a projectile. Aluminum is usually called quasi-brittle material. Aluminum hybrid helmets are a Russian speciality.
The increase in protection capability when hitting metal sheet/plate at an ever-increasing oblique angle increases fastest with steel, then titanium and least with aluminum. So, in other words if you put metallic armor plates (steel, titanium & aluminum) at an equal impact angle you get the greatest boost in protection from steel.
