Chapter 108 You will be the chief gunner!

With "single layer" as a reference, this time Mr. He and his friends knew what the two words "single meat" meant, so they crossed out "dan rou" on the notebook and replaced it with "single meat".

Gao Zhendong continued, "Even if the ESR technology currently being developed is used, after the steel ingot is produced, although the structure is dense, the composition is uniform, and the phase anisotropy is small, there will inevitably be some minor defects, such as shrinkage holes and cracks. In addition, in order to ensure the performance of the gun, a layer of tube was put on the outside. This inevitably leads to problems such as large thickness, heavy weight, and low fatigue life of the gun."

Mr. He and others nodded repeatedly. They knew all this, but how to solve it?

Gao Zhendong started drawing on the paper. Mr. He and the others were excited. "It's started!" He started drawing.

Mr. Guan once said that once Director Gao starts drawing a picture, it means he has good stuff.

People at the Grassland Tractor Factory now know that Gao Zhendong is the director of the first research laboratory of the technical department of the third rolling mill. It is no wonder that he is so capable that he is the director at such a young age.

Gao Zhendong said as he painted: "So I wondered if we could find a way to solve the problem in the gun barrel itself. My idea is that after the gun barrel is bored, a pressure is applied to the inner wall of the gun. This pressure should be much greater than the gun chamber pressure. Through this pressure, the thickness of the gun barrel can be made thinner. The defects on the inner wall of the gun barrel can be squeezed out by this pressure, making the inner wall of the gun barrel tighter. Can this also achieve the effect of a traditional double-layer gun barrel that is hard inside and tough outside?"

Mr. He and his colleagues' eyes lit up. How come they had not thought of this before? By using pressure on a single-layer gun barrel, they could produce a double-layer gun barrel.

Mr. He nodded repeatedly: "Director Gao, your idea is really brilliant. I will go back and think about how to exert this pressure."

Gao Zhendong continued drawing: "I have two ideas, you can refer to them."

Everyone at the Grassland Tractor Factory opened their mouths in bewilderment: What? I haven't figured out one, and you have two? You even gave us a chance to choose? You're such a nice guy.

"The first one is to use mechanical extrusion, using a hard mandrel with a slightly larger diameter, and push it through a hydraulic jack to directly extrude the hole completed by boring. In this way, the above-mentioned effect can be achieved. The advantage of this method is that it is easy to implement, safer, and the pressure requirement for the hydraulic press is not too high. The extrusion process is mainly completed by the mandrel. The disadvantage is that the consistency and uniformity of the inner wall self-tightening are not very good."

The people at the Grassland Tractor Factory didn't even bother to nod. They wrote down Gao Zhendong's words with their pens quickly.

After Mr. He finished writing, he looked up and said to Gao Zhendong, "Director Gao, your idea is very good. It is simple and direct, with low technical difficulty and easy to implement. We will go back and follow this approach and start the experiment soon."

Gao Zhendong continued to talk about his second method: "The second method is to use a hydraulic press, hydraulic self-tightening, fill the barrel with hydraulic oil, connect it to the hydraulic press, and the hydraulic press directly applies pressure to the inner wall of the barrel."

Mr. He thought for a while and said: "Compared with the first method, this method has much better uniformity and consistency in self-tightening, and the product performance is even better."

Gao Zhendong agreed: "Yes, this is undoubtedly a more excellent technical means. However, it also has disadvantages. The technology is difficult and requires higher pressure from the hydraulic press. If the pressure is too high, it is really possible to explode the barrel, instead of just cracking the barrel like the first technology. Fortunately, this technology has an advantage, that is, the pressurized pressure is precisely controllable and can be gradually increased. In the long run, this method has greater potential."

Mr. He compared them for a long time and felt that they were all good. After thinking about it, he decided to take them all.

First use the mechanical extrusion method. This method is really simple, low-cost, the existing conditions are basically mature, and it is very attractive.

It is entirely possible to take advantage of the existing conditions, gain the benefits that can be seen with the naked eye, and suppress the old guy Lao Guan. This method alone can greatly increase the power of existing tank guns without changing parameters such as volume and weight.

At the same time, we are researching the hydraulic method. Even if we can't produce results in a short time, we will be able to produce results after a long time. Then we can upgrade the technology and continue to overcome the old obstacles. It makes me happy just thinking about it.

Thanks to the low cost of mechanical extrusion, two methods can be studied at the same time without much financial pressure. The one that is mature will be used first, and the one with advanced technology will follow later, which is perfect.

After listening to Mr. He's idea, Gao Zhendong also agreed that this was indeed a more prudent and prudent solution. Gao Zhendong also joked: "In fact, the gun steel obtained by VIM+ESR is not the best. VIM+ESR+VAR (vacuum consumable arc melting) can produce better steel. However, the cost of VAR is really high, and the performance improvement is not significant. The cost performance is too low, so it is not necessary."

How low is the cost-effectiveness? For example, Hanscat's Rh120 tank gun uses VIM+ESR+VAR. When the United States introduced Rh120, it found that the cost was too high. Then it improved it and used VIM+ESR. It was found that the performance was sufficient, so VAR was omitted.

Even the United States can't afford it, so it shows how low the cost-effectiveness is.

When Mr. He heard this, he was like, what? There are experts? He didn't care about the cost performance. He just wrote it down first. Whether it can be used or not is another matter.

Gao Zhendong took a sip of water and continued, "After talking about the cannon, let me talk about my thoughts on the bullet."

The people at the Grassland Tractor Factory were a little panicked. Director Gao was a genius, a jack of all trades, and knew everything.

Mr. He listened attentively: "Director Gao, go ahead."

"Mr. He, would you mind telling me what kind of armor-piercing shells our tank guns are using now?"

For someone like Gao Zhendong, this question did not need to be kept secret, so He answered immediately: "Armor-piercing discarding sabot."

Gao Zhendong understood and asked Mr. He: "That's the way to use a sub-caliber armor-piercing projectile. After the shell leaves the barrel, it will be shed to reduce the caliber, reduce resistance, and increase the initial velocity, right?" Mr. He nodded: "Director Gao is a versatile person. He has a deep understanding of the principle. He even understood this at once."

Mr. He believed that Gao Zhendong had never worked seriously with tank shells, but he was able to understand the principle of armor-piercing discarding sabot shells just by hearing the name, which was really amazing.

Gao Zhendong asked: "Have you ever thought about further improving the aspect ratio?"

Mr. He shook his head and said, "Director Gao, you don't know this. When the aspect ratio of a discarding sabot core exceeds 5, the diameter of the projectile is too small relative to its length. It cannot store angular momentum and it is difficult to maintain the rotation of the shell. The flight stability and accuracy of the shell will decrease and it cannot be used."

Gao Zhendong smiled and said, "What if I don't use rotation stabilization?"

"No need for rotation to stabilize?" Mr. He was a little confused.

"Yes, like rockets and missiles, they are stabilized by fins. It's called a fin-stabilized armor-piercing discarding sabot projectile!"

The world's first armor-piercing fin-stabilized discarding sabot (APFSDS) projectile only appeared on the Russian T-1962 tank in 62. It is normal that comrades in China are not familiar with it now.

This sentence was like a thunderbolt that struck Mr. He's brain. Mr. He felt like something was about to pop out of his head, but he couldn't grasp it for a moment, and felt very uncomfortable.

If the tail is stable, there is no need for rotational stability, and the limitation of the aspect ratio can be broken through.

The larger the aspect ratio, the faster the initial velocity of the projectile and the longer the length of the armor-piercing body.

The longer the armor-piercing body, the heavier it is, and the better the speed retention performance.

The faster the speed and the better the speed retention, the higher the penetration.

Although the penetration depth is not proportional to the length of the armor-piercing body as rumored later, within a certain range, the length of the armor-piercing body has a positive effect on the penetration depth.

Mr. He felt that he had been taught a good lesson today. He thought that Gao Zhendong's suggestion to increase the aspect ratio was layman's talk, but he did not expect that he had studied it more deeply, thought more, and went further than himself, and he actually added the aspect ratio.

It took Mr. He a long time to come out of his shock and shame. He said to Gao Zhendong: "Director Gao, your words really woke me up! I am ashamed and admire you!"

At this time, a technician from the Grassland Tractor Factory asked, "Director Gao, but the rotation of the shell will affect the stability of the tail wing. Won't it still be unstable?"

Gao Zhendong laughed and said, "Then we can use smoothbore cannons. Who said we must use rifled cannons?"

When Mr. He heard this, he was like, “Great!”
Rifled cannons replaced smoothbore cannons because they can give the shells rotation, which can increase the flight stability of the spindle-shaped shells and greatly improve accuracy.

But unexpectedly, here, Director Gao came up with a very ingenious idea and used the characteristics of the smoothbore gun to eliminate the rifled gun. It was brilliant, really brilliant.

Who says that tanks must use rifled guns? The range of tank guns is only a few thousand meters. Why would you need a rifled gun within this range?

With the tail fin stabilization, the missile can fire as accurately as a smoothbore cannon, and can even achieve better results than rotational stabilization.

The smoothbore gun has a simple structure and is easy to process. It is perfect for use with the self-tightening barrel. It is amazing. Director Gao's combo is linked together and echoes each other. It is simply tailor-made for tank guns. If anyone says that Director Gao has never learned anything related to artillery, I, Old He, will be the first to disagree.

Lao Guan, just wait. This time when we go back, I, Lao He, will have plenty of things to serve you!

Everyone at the Grassland Tractor Factory was stunned by Gao Zhendong's skills and it took them a long time to recover.

A technician asked the final question: "Director Gao, what about other types of ammunition? Without rifling, other types of ammunition such as high-explosive grenades and armor-piercing shells will lose their rotation, so they will not be able to hit accurately, right?"

Gao Zhendong laughed loudly. Before he could answer, Mr. He slapped him on the head: "You are stupid, why not use the tilted tail to make them rotate?!"

It is said that Mr. He is the chief engineer of guns and artillery. He has a quick reaction and immediately draws inferences from one instance and finds a solution to the problem.

Mr. He turned around and held Gao Zhendong's hand: "Director Gao, don't say anything, you will be the chief gunner!"

(End of this chapter)