Liushugou, Electric Furnace Steel Plant.

Two two-roll cross-rolling mills are installed here, one for rough rolling and one for finish rolling. Professor Zhuang, Lin Wan, and Chen Kang gathered here and waited quietly. On the side, the steel mill workers were following the instructions to prepare for rolling.

The core bar of the rough rolling mill is turned and its diameter is shortened from 60 mm to 56 mm. The rolling process is divided into two steps. The solid blank is heated and extruded through the rough rolling mill to obtain a seamless steel pipe with an inner diameter of 56 mm.

The diameter of the mandrel of the finishing mill is 59 mm. When the 56 mm inner diameter seamless steel pipe passes through the 59 mm diameter mandrel, an internal extrusion effect will be produced, similar to the self-tightening effect of the artillery barrel. After this process, the quality of the mortar will be improved.

and lifespan will be improved by two orders of magnitude.

The seamless steel pipe rolled by the finishing mill has a theoretical inner diameter of 59 mm. It is then precision processed to remove the burrs on the pipe wall, and a high-quality 60 mm mortar pipe is obtained.

Finally, it is up to the customer's needs to decide whether to engrave rifling. Mortars are generally smoothbore, but rifling can also be processed to make it a rifled mortar to improve shooting accuracy.

This is the seamless steel pipe rolling process formulated by Zhuang Jiao.

In the forging workshop of the electric furnace steel plant, an epic steel symphony is being staged.

More than a dozen workers are performing manual forging of solid blanks, and the so-called manual forging is the most original and passionate method.

A six-and-a-half-meter-high steel frame is erected in the middle. The steel frames on both sides are equipped with guide rails. A square solid steel slider weighing 300 kilograms is suspended from the top. The slider is connected by two steel cables, and the steel cables are connected to the steel frame.

The top pulley group then extends to the left and right respectively, and the end is connected to two human-powered winches.

The shape of the entire machine is perfectly similar to the Louis XVI pleasure table. The biggest difference is that one is used to behead heads and the other is used to forge steel.

Emmmm…

If you have to use this thing to behead your head, it's not impossible.

The hoisting device is manually driven to pull the 300kg slider up to a height of 6 meters, and then lowered for free fall. The kinetic energy of a single impact is as high as 5400 Joules, thus achieving the forging effect.

Needless to say, although this artificial forging method is crude, it is extremely practical.

Regardless of the forging efficiency, only the impact kinetic energy is considered. This manual forging press with a 300 kg slider is equivalent to the impact kinetic energy level of a 250 kg air hammer.

The shortcomings are quite obvious...

slow.

The frequency of a single strike is about once every 20 seconds.

Fourteen strong workers were seen turning the hoisting device each, quickly driving the 300 kilogram slider upwards. When it reached the six-meter limit, they immediately released the handle of the hoisting device, and the slider fell at high speed like a meteorite.

, just a few tenths of a second later, it hit the rectangular steel ingot placed on the surface of the anvil.

"Boom!" A dull and powerful sound of metal impact came out, and the fiery red steel ingot deformed instantly. Two forgers, one behind the other, turned over the ingot with iron tongs.

The entire forging process must forge the rectangular steel nail into a nearly round shape, and then reheat it before rolling.

"Who designed this artificial forging press?" Zhuang Qianding asked curiously as he looked at the forging press in the workshop that looked particularly like Louis XVI's guillotine.

"It was designed by Li Qiang during the Guantian General Arsenal, but due to the Long March, it could not be used at that time. Not long ago, we found the design drawing of this artificial forging press and built it." Chen Kang responded with a smile: "Professor Zhuang,

Do you think there is any room for improvement?”

"This forging press is perfect with only manual drive. If I improve it, I can only change it to electric drive and add a set of transmission devices to amplify the torque twenty times and drive the one-ton slide to increase the forging efficiency."

Zhuang Qianding responded: "But it is too time-consuming and costly, and the German-made air hammer will arrive at the base immediately, so there is no need for improvement."

It can be improved, but it's not necessary.

If there is no German-made mechanical processing equipment, then there is no problem in modifying this manual forging press.

"Boom! Boom! Boom!"

The sound of the metal slider hitting the high-temperature steel ingot in the workshop was continuous, as clear and sweet as the running water in the mountains, and as powerful as the majestic mountains. Half an hour later, the steel ingot that had been forged hundreds of times had approached the shape of a cylinder, and the forging

The workers put it into the furnace for reheating.

Since the industrial version is limited to 0.2 and lacks a thermometer, it is impossible to accurately measure the temperature of the steel ingot. To what extent the temperature can eventually recover can only be determined by feeling.

This feeling is how workers feel that the temperature is acceptable - visually measured below 10,000 degrees Celsius, around 1,000 degrees Celsius.

When the nearly cylindrical steel ingot turns yellow, the forger feels that the temperature is about the same, takes it out, and sends it to the first two-roller cross-rolling mill that is responsible for the rough rolling process.

Everything is ready.

"Report, the rolling work is ready, please give instructions!" Seeing this, the director of the electric furnace steel plant immediately raised his hand and saluted Chen Kang.

Chen Kang raised his hand in return: "Proceed as planned."

The two two-roll cross-rolling mills have been debugged. Professor Zhuang personally trained a group of rolling workers for the electric furnace steel plant and compiled relevant production regulations. This rolling is the first rolling test. Once successful, it will enter the trial production phase.

"Yes!" The factory director turned and left.

"Professor, it's about to begin." Chen Kang looked at the rolling test that was about to begin, with some anticipation in his heart.

From the perspective of the electric furnace steel plant, the success of the first rolling test means that the electric furnace steel plant has the ability to manufacture seamless steel pipes. Compared with the previous situation where it could only cast steel ingots, it can be described as a historic breakthrough.

From the perspective of an arsenal, the success of the first rolling test represents a substantial breakthrough in the biggest technical problem of the 60mm mortar project, and the entire weapon imitation research and development project is about to succeed.

For the Military Industry Bureau, this shows that the Military Industry Bureau is about to have the ability to independently produce 60mm mortars. Compared with the past, Chen Kang can only describe it as "the road through Xiongguan is as solid as iron, but now we are leaping forward from the beginning."

Zhuang Qianding nodded, with a smile on his face and a trace of expectation in his eyes. He wanted to see the final effect of the two-roller cross-rolling machine that incorporates the self-tightening technology concept of artillery barrels.

Following the order from the director of the electric furnace steel plant, all power supplies in the electric furnace steel plant were centralized to ensure the supply of the rolling mill. The already prepared rolling group started the machine, and the DC motor with a power of up to 50KW was running, staying in the groove-shaped rolling table.

The tail of the fiery red nearly cylindrical blank slowly moves forward under the action of the metal head.

Immediately afterwards, the head of the billet contacted the metal cast iron roller running at a constant speed. In an instant, the head was subjected to the reaction force exerted by the upper and lower parts, and its shape changed, resulting in a squeezing effect. The surface iron oxide fell off like dandruff, and the billet

Continuing forward, the head of the changed billet comes into contact with the conical mandrel. Under the strong rolling force and the top of the tail, the solid billet is forcibly squeezed out of a hole.

Slow and steady.

The metal head continues to move forward, and the two rollers apply pressure evenly. The entire blank changes from a solid state to a fiery red hollow steel pipe at a speed visible to the naked eye.

A few minutes later, the one-meter-long blank completed the rough rolling process and became a high-temperature seamless steel pipe with an inner diameter of 56 mm. After the rolling worker checked that there were no cracks or bubbles on the surface of the steel pipe, the rough rolling mill was immediately closed and sent to the finishing mill.

Due to insufficient power supply, the electric power of the electric furnace steel plant can only maintain the full power operation of one rolling mill, which is very embarrassing. Both rolling efficiency and electric furnace smelting efficiency are greatly reduced.

Regarding this problem, Chen Kang cannot solve it for the time being, so he can only temporarily use the current method and turn it on intermittently.

Two rolling workers in the finishing group started the machine, and the metal head pushed the high-temperature seamless steel pipe with a slightly lowered temperature forward, contacting the cast iron rolls rotating at a constant speed, and the shape became more rounded. Then, the most important link came, when the steel pipe head came into contact

59 mm diameter mandrel.

Extrusion, deformation.

A force is exerted from the inner wall tissue to the outer wall tissue, and the inner wall tissue of the steel pipe becomes denser, while the outer wall is affected by the mandrel shell and cannot move, thus producing a self-tightening effect of the tube.

As time passed, under the gaze of everyone, a yellow-red seamless steel pipe gradually emerged from the other end of the mandrel, with an inner diameter of 59 mm and an outer diameter of 8 mm.

Seeing this scene, all the onlookers around were refreshed.

A few minutes later, the second cross-rolling mill was shut down, and the entire finishing rolling process was completed. A 59 mm diameter high-temperature seamless steel pipe lay quietly on the surface of the workbench, with a length of about one meter and two meters.

After the finishing rolling process was completed, Zhuang Qianding and Lin Wan, as developers, stepped forward together to conduct the final quality inspection and acceptance link of the production process.

If the quality inspection fails, it will mean that the entire seamless steel pipe is declared scrapped.

Chen Kanghe, the director of the Electric Furnace Steel Plant, and all the workers held their breaths and stared intently at Zhuang Qianding, who was the top high-tech team member.

A total of four rolling workers in the rough rolling group and the finishing group looked nervous and felt a little uneasy. They kept recalling the rolling process just now, for fear that the test results would be unqualified.

After a few minutes.

"Professor, how are you?" Chen Kang waited for Professor Zhuang to finish the all-round inspection of the seamless steel pipe, then stepped forward and came to his side, asking with concern.

"There are no cracks, bubbles or holes on the surface of the outer wall of the steel pipe. It can be seen with the naked eye that the inner wall is denser than the outer wall. It basically achieves the self-tightening effect of one-time finishing rolling. The first rolling test was very successful." Zhuang Qianding motioned to Lin Wan on his left to record this time.

After testing the results, he then faced Chen Kang and announced the quality inspection results with a smile.

"Okay! Okay! Professor, what should we do next?" When Chen Kang heard this, a look of joy suddenly appeared on his face. He was very excited, but he kept calm and asked.

The factory director and the surrounding workers were relieved, and their faces were filled with joy. The other two rolling crews finally breathed a sigh of relief, and felt a sense of joy and success involuntarily.

success!

This is a small step for the Liushugou Electric Furnace Steel Plant, but it is a big step for the base area and the Red Army to independently produce weapons and ammunition!

"Let the workers send this seamless steel pipe to the annealing furnace, anneal it to remove stress, and then pickle it to make a qualified gun barrel blank and send it to the arsenal."

Zhuang Qianding nodded and arranged in an orderly manner: "In terms of production, two rolling mills can be put into trial production to manufacture gun barrel blanks in small batches."

The seamless steel pipe that has gone through the finishing process cannot become a mortar tube blank for the time being. It needs to undergo two processes of annealing and pickling. The seamless steel pipe made of electric furnace steel can finally become a gun barrel blank and be sent to

Arsenal processing.

The gun barrel blank is produced by the electric furnace steel factory, and the precision processing is handled by the arsenal. Each performs its own duties and cooperates with each other.

The blank material needs to go through two processes of turning and precision boring to make the outer wall smooth and rounded, and the inner diameter to reach a length of 60 mm. In this way, a barrel blank material can truly become a mortar tube.

Of course, due to the lack of machine tool equipment, mechanical processing can only perform outer wall turning, and inner wall boring processing is temporarily unavailable.

"Okay, Lao Liu, you can arrange a team here to start the production of seamless steel pipes. First, conduct trial production for a period of time to accumulate experience in the production of gun barrel blanks. The power supply can only maintain the current level for the time being. You have to base it on

The electric power supply arranges the production tasks of the electric furnace and the two rolling mills reasonably, but I can ensure that I have at least 5 gun barrel blanks every day."

Hearing Zhuang Qianding's arrangement, Chen Kang nodded, turned to look at the factory director Liu Cheng beside him, with a serious face, and issued an order: "This is an order!"

"Yes, the Electric Furnace Steel Plant guarantees its mission! Old chief, if I don't produce five barrel blanks every day, you will twist off my head!" Liu Cheng, the emotional director of the factory, suddenly raised his chest and raised his hands.

He saluted and shouted loudly, showing a strong temperament of an iron-blooded soldier.
To be continued...