A tank is an iron lump, and to build a tank, you can't do without a steel plant.

However, ordinary steel cannot be directly used as the armor of a tank, after all, the tank is going to go to the battlefield and is going to be shot and rained. In order to be able to block shells, the harder the armor steel, the better.

During the First World War, riveted armor was used, and these special steel armors were heat-treated to have a high degree of hardness, but later, they were changed to a welded structure, and the hardness was slightly reduced in order to be able to weld them.

This hardness value is measured by a special hardness value called Brinell hardness (HBW), and at that time, it was possible to achieve 390HBW of thin armor and 220HBW of thick armor.

After the end of World War II, the development of armor steel is also going on, of course, the most commonly used, or homogeneous armor, this kind of armor has a complex process, first to heat to more than 800 degrees, and then quenched in oil or water for hardening. However, the treated steel plate is hard and brittle, so it needs to be tempered for several hours in a furnace of 400 to 600 before the final product can have the right toughness and rigidity of homogeneous steel.

At the same time, in order to make the steel have qualified quality, different factories have also added different rare metals to it, such as Germany, which uses manganese steel, which is mixed with manganese elements, while the Soviet Union uses molybdenum-nickel alloy steel.

In the later period, due to the lack of resources, manganese ore could not be obtained, and Germany used ordinary high-carbon steel with surface hardening, and as a result, the ballistic performance went down a notch.

And for the country, the tank industry in the early years, which was built entirely with the help of the USSR, 59 tanks, in fact, were T-54A.

However, just when the tank industry was just beginning to be built, relations with the Soviet Union were stiffened, and the Soviets withdrew all their specialists and technical forces, and then, let it out, tanks, you will never be able to build them!

That's right, the big countries in the East at that time were poor and white, there was nothing, and the steel needed to build tanks was not smelted!

How can you build a tank without even a qualified armor steel?

However, these difficulties can not be difficult for the builders of the motherland, in the grassland iron and steel plant, countless people are fighting, after the establishment of the No. 1 blast furnace of that year, it was the big leader who personally came to cut the ribbon, which is the only one in the country, and also established a special rare earth experimental plant.

That's right, the armor steel used in domestic tanks is also unique, that is, rare earth armor steel.

The country has been prospected, rare earth resources are abundant, so, the country began to plan to build special rare earth steel, but, at that time, the domestic rare earth production technology and technology is still very backward, the United States monopolized the supply of global rare earth resources, and regarded it as highly confidential and blockaded, this is of course difficult for the sons and daughters of the republic, after several years of research and development, the rare earth armor steel codenamed 601 was smelted, not worse than the quality of the original Soviet armor steel.

The current 59, 69, 79, 80, these tanks are all codenamed 601,602 of these rare earth armor steel.

However, technology always has to evolve, with the development of the times, the wave of composite armor has gradually risen, it is unrealistic to rely on steel armor alone to block armor-piercing shells, it is necessary to have advanced composite armor.

Composite armor is a multi-layered structure with steel on the outside and a non-metallic structure on the inside, fiberglass, ceramic, and other structures.

At this time, higher requirements were put forward for armor steel.

The Prairie Iron and Steel Plant has not been idle, it has been constantly conducting research and development, and now the results have finally come out, and the armor steel codenamed 623 has been smelted from their blast furnace!

Speaking of which, this is the first time Qin Zhenhua has come to the grassland iron and steel plant, although it is a brother unit, but Qin Zhenhua is usually too busy, and the cooperation of this kind of brother unit has always been harmonious, there is no contradiction, and there is no need to mediate.

When Qin Zhenhua and Zhao Guodong came to the grassland steel plant together, and brought a howling fat pig, Ma Hui, the person in charge of the steel plant, came up to greet him with a smile.

"Welcome, welcome. Since the new leadership team of a machine factory came to power, it is the first time we have met. Ma Hui came up and said jokingly: "This, you can't blame us, the main thing is that you didn't bid for the armored steel, otherwise, my old horse, I have to go over with my eyes, holding a sign and waiting for the bidding, if you don't want our armor steel in a machine factory, our grassland steel factory, we have to drink the northwest wind." ”

In the seventies and eighties, there was no beginning of yellow sand control, speaking of the wind and grass and low cattle and sheep of the grassland, in fact, once the wind rose, the sky was full of yellow sand, and the climate was not good. Drinking the northwest wind, that's quite uncomfortable.

Ma Hui laughed like this, Qin Zhenhua also laughed: "Director Ma, you are joking, we are bidding for parts, the armor steel of the tank hull, if your steel factory does not provide us with it, then we should take the initiative to come to the door and hug the thighs." ”

"Haha." Everyone laughed loudly, and they felt that the title of hugging the thighs that Qin Zhenhua said was very appropriate.

"Okay, long story short, I'll take you to see the 623 armor steel first." Ma Hui said: "Since the higher authorities issued instructions to engage in second-generation tanks and third-generation tanks, the responsibility of researching new armor steel has fallen on us. ”

Speaking of rare earth steel, we can't fail to mention Professor Xu from the country's highest university, who first developed 601 armor steel, developed rare earth separation technology, and now, helped develop 623 armor steel.

"According to the requirements of composite armor, our armor steel is made of double-hardness steel." As he walked, Ma Hui introduced to everyone: "It can be used in the outermost layer of composite armor, and it can directly affect the surface armor of light armored vehicles. ”

"Double hardness steel? That's a good thing. Qin Zhenhua immediately sighed and said, as a tank technician, of course he knows the key to this.

The harder the armor, the more brittle it will be, so this is a contradiction, how to avoid this contradiction, there are many ways to think of it, and double hardness steel is a method.

The surface layer is particularly hard, which can deform the projectile when blocking the projectile flying over, or even break directly, while the bottom layer has low hardness, and at the same time the ductility and toughness are very good, so that if there is a crack on the surface, it will not expand to the inner layer, which is the benefit of double hardness steel: so that a material has both hard failure and toughness absorption characteristics.