my scientific age

Chapter 396 Interference assembly!

The cold metal parts, the huge breech block full of texture, the thick and heavy gun mount structure, it stands there quietly, silently, exuding a faint aura.

Perhaps, this is the sense of security that soldiers need in times of war.

Bring destruction and death to the enemy, and bring victory and hope to the soldiers.

"Prepare the slewing bearing assembly." Yu Hua carefully checked the gun mount structural parts according to the procedure, confirmed that they were correct, wiped the sweat from his forehead, and spoke in a serious tone.

The slewing bearing is a special bearing with a special structure. It can rotate 17 ​​degrees, transmit and fix, and is multifunctional and multipurpose. It first came into the world's attention during the First World War when the French Renault FT- ultra-light tank was born. This was the world's first tank equipped with a rotating turret. The reason why this tank can rotate the turret is that it uses a slewing bearing, which can adjust the turret angle at will and strike targets from all directions.

As the core combat component of the Red Peony Howitzer, this slewing bearing is made of special steel with high hardness and high wear resistance. It has a working life of 50 hours and needs to be lubricated every 30 hours. The rotation accuracy is one degree and the combat fixing accuracy is one arc minute. The operating temperature range is ℃ - minus ℃, which can meet the harsh working conditions of most battlefield environments.

Of course, if it is an extreme low temperature environment in the three northeastern provinces, it is necessary to develop a more cold-resistant special grease to meet the usage scenarios of the extremely cold weather in the three northeastern provinces. However, for the Eighth Route Army at this stage, entering the three northeastern provinces to fight is too far away. The performance indicators of the slewing bearings currently equipped with the Red Peony howitzer are sufficient.

Two professionally trained soldiers followed the standard procedure and pushed a heavy-loaded flatbed transport truck slowly towards the No. 1 assembly point. On the transport truck was a slewing bearing assembly with a diameter of 1.5 meters and a weight of more than 400 kilograms. The entire assembly was in a fully assembled state, with brand new mechanical butter filled inside, the inner and outer rings tightly connected, and dotted with ball bearings made of wear-resistant steel, forming a precise and complex support structure foundation.

"Squeak!" The transport vehicle stopped steadily in the waiting area of ​​assembly point No. 1.

Afterwards, the small crane started to operate, and two soldiers cooperated with it, using lifting belts to tie the slewing bearing, lifted it steadily and transferred it to the assembly point operating table, and then put it down steadily.

When the slewing bearing assembly was ready, Yu Hua nodded and made a gesture. The four soldiers on standby nearby immediately stepped forward, used lifting belts to secure the heavy gun mount foundation, and then used a small crane to lift the gun mount foundation and place it above the slewing bearing assembly.

The gun mount base slowly descended and got closer to the slewing bearing. Four soldiers assisted the crane operator in the docking operation to ensure that the screw holes between the two were accurately docked.

The entire docking process was slow and careful. A thin layer of sweat oozed from everyone's forehead. Everyone was extremely cautious, fearing that any mistakes would occur.

The things in front of them are too precious and too important. They are not qualified to make mistakes, let alone bear the consequences of making mistakes.

Feeling everyone's nervousness, Yu Hua did not say anything to comfort them. Instead, he let them experience the nervousness carefully and learn from it.

Military production is no joke. Any mistake in the production stage may result in serious damage to collective assets at the very least, or even lead to combat failure or even the loss of lives of frontline soldiers.

There must be a string in the minds of military workers that is kept taut and can never be relaxed.

This may be cruel to humans, but there is no other way.

When the gun mount base and the slewing bearing are about five millimeters apart, the crane is hovering and the four soldiers cooperate to slightly adjust the angle between the two components to fix them. After Yu Hua checks and confirms that there is no problem, he gestures to the crane, and then the gun mount base slowly falls onto the surface of the slewing bearing assembly.

Thirty-six screw holes are precisely connected.

After the docking was completed, Yu Hua signaled the four soldiers of the assembly team to tighten the screws. Seeing this, the four did not hesitate and immediately got busy. They picked up the torque wrench to set the corresponding torque, took out the dedicated screws, and carried out the screw tightening operation according to regulations.

standard!

The entire assembly process is carried out in accordance with the pre-established "Heavy Artillery Standard Assembly Manual", and any assembly operations or personal behaviors that violate the assembly manual are strictly prohibited.

As a later generation, Yu Hua is well aware of the importance of standardization. Big Brother taught him the skills of a complete industrial system, and the Americans taught him the secrets of the standardization system. The combination of the two has made our motherland known as the world's factory and laid the most solid foundation for its prosperity.

Setting the standard, having it all.

Of course, this is far from formal standardization. What Yu Hua did was only to create an environment for the standardization system to take root in the base.

Under Yu Hua's arrangement, the four soldiers methodically tightened the screws to firmly fix the base of the gun mount on the slewing bearing assembly. After completing this step, the entire artillery had a clearer outline.

Without wasting time, Yu Hua and all members of the assembly team continued the assembly work, installing parts one by one on the body of the Red Peony Howitzer, including the cradle, balance machine, steering machine, elevation machine, optical gun sight, angle table...

With the installation of the triangular auxiliary hoe and the moving body assembly connected to the base of the gun mount, the gun mount of the Red Peony Howitzer has been assembled. Now, only the last core component is left - the gun body!
At this time, no one knew how much time had passed. There was already a huge crowd outside the artillery assembly workshop, led by the instructor and the boss, who were smoking and chatting with smiles on their faces. On their left and right were familiar Eighth Route Army leaders. Li Qiang, the head of the Military Industry Bureau, served as a tour guide, constantly explaining the artillery assembly process and the function of each component.

The crowd was bustling, but no one came to disturb Yu Hua.

Everyone understood the importance and significance of this moment and they waited patiently to witness history.

Yu Hua glanced outside without saying a word. He stared at the Red Peony Howitzer in front of him. He picked up the cup and took a sip of water, then signaled to start work.

The Red Peony's gun body components are relatively simple, consisting of a 105mm 23-caliber barrel, a sleeve and a breech block, without any fancy gun smoke exhaust devices or muzzle brakes.

The artillery smoke exhaust device requires drilling a hole in the barrel to install an air chamber. This design places extremely high demands on the quality of the barrel. The slightest carelessness will cause the barrel to explode, and it is not suitable for towed howitzers.

As for the muzzle brake, it is not needed at all. The working principle of this part is to reduce the recoil of the artillery by lowering the chamber pressure inside the tube. The problem is that the double-chamber hydraulic recoil brake of the Red Peony Howitzer can easily withstand the recoil of the launch, and there is no need for a muzzle brake to reduce the chamber pressure at all.

What does it mean to reduce chamber pressure?
The initial velocity of the shells decreases and the range is shortened!

Sorry, what we want is great power and might!
The higher the firing chamber pressure, the better; the higher the initial velocity of the shell, the longer the range, and the stronger the firepower!
The initial velocity of a shell at 600 meters per second and the initial velocity of a shell at 900 meters per second are two completely different concepts.

Yu Hua was in charge of the command, and four soldiers performed auxiliary operations. They first carefully installed the conical sleeve used to improve shooting accuracy and lifespan onto the gun mount. As the heavy artillery-grade barrel self-tightening technology had not yet been broken through, they could only put some effort into the gun sleeve and took the conical sleeve used in later artillery.

The overall performance of the tapered sleeve is superior to that of the traditional sleeve. The sleeve itself gradually becomes thinner from front to back, which is not only lighter, but also can withstand firing stress and heat more evenly.

The breech block had been installed before. After the conical sleeve was installed, Yu Hua came to the parts table. The more than two-meter-long gun barrel was fixed upright, and the lower ninety centimeters was placed in a round metal container with a diameter slightly larger than the gun barrel.

The man exhaled lightly, then opened the liquid nitrogen bottle and poured the extremely expensive liquid nitrogen into a round metal container. White extremely cold mist spread everywhere, and a bone-chilling chill came with it.

Big factories are freezing, small factories are burning, and roadside stalls are clanging.

In order to ensure the assembly accuracy and quality of the gun barrel to the greatest extent, Yu Hua specially chose liquid nitrogen freezing assembly technology. The diameter of the gun barrel that has been frozen with liquid nitrogen will be shortened by a few millimeters, which is just enough to fit into a conical sleeve of the same diameter. After returning to normal temperature, an interference fit is achieved between the gun barrel and the conical sleeve, so that the two rely on the elastic pressure of the contact surfaces to produce a tight and firm connection.

Liquid nitrogen freezing interference fit assembly is the most popular assembly method among major machinery manufacturers in later generations.

The gun barrel cooled down rapidly under the influence of liquid nitrogen, and the diameter of the affected part shortened slightly. Yu Hua stood at the operating table and counted the time. After the predetermined cooling time was reached, he immediately gave instructions to the crane.

Low-temperature frozen parts cannot be overcooled. If overcooled, the metal will become brittle.

The crane started to move, lifting the heavy gun barrel vertically upwards. The part below the barrel where condensed crystals had formed slowly came into Yu Hua's sight until it left the round metal container.

The breeze is gentle and the timing is perfect.

Yu Hua gave the order and four soldiers assisted in the operation, cooperating with the crane to lift the gun barrel to the front of the conical sleeve as quickly as possible, and then adjusted the angle.

The barrel is pointed vertically downward with the breech block aligned with the conical sleeve hole.

The crane slowly descended, and the low-temperature frozen breech block effortlessly entered into the conical sleeve hole of the same diameter, little by little, until it was submerged in it.

The whole process is smooth and silky.

Seeing the frozen part of the gun barrel installed so easily, Yu Hua showed a satisfied and comfortable smile on his face. He nodded lightly. He felt extremely comfortable and the tense nerves in his heart slowly relaxed.

He did it.

It had been nearly ten months since he traveled through time, and he had done it with his own hands and brain - in northern Shaanxi in 1937, he had developed a large-caliber heavy artillery for the troops.

Has history changed?

He doesn't know anymore.

But he knew that with the base equipped with large-caliber heavy artillery and the Eighth Route Army, more Japanese troops would be destroyed!
The heavy machine gun developed by Maxim wiped out 47 British troops in one day in the Battle of the Somme. The AK- developed by Kalashnikov has been killing lives since its birth. It has been produced in the tens of millions, and the number of souls who have died under its gun is no less than its production figures.

Yu Hua did not expect the Red Peony Howitzer to destroy millions of Japanese troops. He only hoped that every shell fired would take away at least one Japanese soldier, and use the lives of the Japanese soldiers to soothe his soul. That would be enough.

What is success?

Whenever I think about the Japanese soldiers on the battlefield dying because of the artillery I developed, I feel that this is a success.

Of course, this is just a kind of success. He has never forgotten his original dream of Miss Qiu.

At 1937:10 p.m. on October 4, 08, the Red Peony 105mm prototype gun was assembled at the Liushugou Arsenal in the base area, and China's first independently developed large-caliber howitzer was born.