This time he came to Liushugou mainly to solve the problem of seamless steel pipes for the mortar project of the arsenal. He had originally planned to build a cross-rolling mill, and Yu Hua's idea coincided with his.

"Yes, yes...Professor Zhuang, I will take you there, please follow me." Zhao Shu reacted immediately and realized what this moment meant. He was a little incoherent and showed excitement, so he answered quickly.

Not only Zhao Shu, but section chiefs Hu Zhigang and Zhao Zhangcheng were equally excited. After all, the two-roller cross-rolling mill was built to produce mortars.

But that's not the point.

The important thing is that they can make their own two-roll cross-rolling mill, the core equipment for producing seamless steel pipes!

When things had developed to this point, there was no need to go to the arsenal for the time being. The group quickly rushed to the sand foundry workshop of the iron plant. Next, Zhuang Qianding and Yu Hua quickly constructed the design drawings of the two-roller cross-rolling mill and initially determined the size and shape of the rolls and mandrels.

.

The core rod has a diameter of 60 mm, a length of 1 meter, a cylinder, and a theoretical weight of 21 kilograms.

The roller has a diameter of 180 mm, a length of 1 meter, a cylinder, and a theoretical weight of 190 kg.

This is a two-roll cross-rolling machine with a net weight of about 500 kilograms. It has no flat outer shell packaging, no electronic equipment, no various precision measuring instruments and control systems. It only has a mechanical structure composed of two rollers and a mandrel. It is extremely simple.

The entire two-roller cross-rolling mill is driven by a high-power DC motor, which amplifies the torque through the transmission system and applies a maximum rolling force of 300KN.

After finalizing the design plan, Zhuang Qianding, accompanied by Hu Zhigang and Zhao Zhangcheng, the chiefs of the ordnance industry department, rushed to the arsenal and prepared to use the arsenal's ordinary vehicles to open molds.

Yu Hua stayed at the iron factory to witness the official opening of the first blast furnace in the Shaanxi-Gansu-Ningxia Border Region for ironmaking.

…

Escalators were built at the feed inlets on the left and right sides of the blast furnace. The former director, Ma Tian, ​​and a Red Army soldier were carrying full wooden barrels. One barrel contained sintered iron ore as big as glass beads, and the other one contained

It is coke, which is poured into the funnel-shaped feed port in an orderly manner.

Steam is rising at the feed inlet, and fine coal powder and diesel fuel burn violently, and then a steady stream of heat is released under the action of the blower, igniting coke and sinter.

One barrel after another, factory director Martin and the soldiers poured barrels of raw materials into the blast furnace like tireless machines.

Apart from anything else, the conveyor belt must be clicked out immediately. - Yu Hua looked at the blast furnace charging process. Director Ma Tian and the soldiers on the escalator were exhausted and sighed softly.

The entire manual loading process is slow, laborious, and extremely inefficient.

Two tons of pig iron, according to the smelting level of the indigenous blast furnace, requires at least four and a half tons of sinter and one ton of coke. These smelting raw materials are all put into the blast furnace manually. How much time does it take?

"What's wrong?" Sensing something strange about Yu Hua, Lin Wan, who was holding a notebook and pencil to record information, turned around and asked with concern.

"We should manufacture conveyor belt equipment as soon as possible, otherwise, we can't accomplish great things by relying on manpower alone." Yu Hua stared at the sweaty factory director Ma Tian and the Red Army soldiers, and said softly.

He admired the factory director Martin who took the lead in loading the materials himself, but in terms of the efficiency and time of manual loading, it was far inferior to the power of machinery.

Conveyor belt is a kind of mechanical equipment that transports materials in a systematic and highly automated manner. Even though it is ordinary, it may not seem like a big deal. In fact, it is one of the greatest inventions in the history of human civilization. The reason why modern industry can be so developed is

Conveyor belt equipment should account for at least three-thirds of the credit.

With its ultra-high conveying efficiency and extremely simple principle structure, in terms of conveying materials alone, the conveyor belt equipment can completely outperform transportation vehicles such as trains and ships.

"It is true that manual loading is time-consuming and laborious, but I don't know much about conveyor belt equipment. For the time being, I can only help you get started and learn through practice." Lin Wan heard this and nodded, expressing her support. She knew about the conveyor belt equipment.

importance, but due to limited academic level and knowledge reserve, I don’t know much about the mechanical structure and principles of conveyor belts, so I can’t share the research and development work for Yu Hua.

Of course, there is no problem in being a helper. After all, she is also a top student admitted to Peking University.

"It's enough if you can strike. Come on, Jinyu." Hearing this, Yu Hua smiled slightly and stretched out his right hand.

"Come on, Yu Hua."

Lin Wan smiled and nodded, raising her right hand.

"Pa!" The two right hands slapped each other to express the most sincere blessings.

The charging of the blast furnace continued. After an hour, director Martin and the Red Army soldiers reached their physiological limits and had to be replaced to continue loading and delivering raw materials.

A total of 11,000 kilograms of iron ore and coke took two hours to process.

After all the raw materials are loaded, the feed port is closed.

The high-power blower arranged under the blast furnace operates at full capacity. The coke, which is the main heat source, burns violently and releases a high amount of heat. The temperature inside the blast furnace quickly rises to about 1,450 degrees Celsius. The iron ore, which is already in a softened state, is heated at high temperatures.

It gradually melts after reacting with limestone to form orange-red molten iron, with a layer of liquid slag gradually floating on the surface.

The reaction process inside the entire blast furnace is very complex.

As time slowly passes, more and more iron ore is melted into molten iron, forming a molten pool below the blast furnace.

Outside the blast furnace, harmful exhaust gas containing various substances continued to emit from the top exhaust vent, floating into the blue sky, polluting the surrounding air. Standing at a safe distance, Yu Hua, smelling the smell coming from the steel industry, felt sleepy.

Feeling relaxed and happy.

This taste is very good.

When the smelting process was one-third complete, guard Xiao Li and two soldiers rushed over, carrying the newly smelted ferrosilicon inoculant.

Immediately afterwards, Professor Zhuang and his team appeared one after another. Hu Zhigang was holding a cylindrical roller standard mold, and Zhao Zhangcheng was holding a 60mm mandrel standard mold that was like a gun barrel. The molds were all made of elm wood, which saves time and effort.

The mold and ferrosilicon are in place and everything is ready.

The skilled workers in the sand foundry workshop of the iron factory are making sand molds for rolls and mandrels as quickly as possible. These skilled workers are all from the arsenal workers before the Long March. They have worked in major factories in the Republic of China and are skilled and experienced.

Although they don't know much about mechanical principles and mathematical calculations, they have extremely rich front-line practical experience. They are extremely familiar with sand casting and pouring molds. If it were left to Japan, there would be a sand casting immortal.

Before the first blast furnace of Liushugou Iron Works produced molten iron, the sand molds for four rollers and two 60mm mandrels were successfully prepared and transported to the blast furnace to wait for the molten iron.

As time passed by, more and more people gathered around the blast furnace of the iron factory. Chen Kang, the top technical team, heads of departments of the Military Industry Bureau, heads of major factories, and General Liu who came after hearing the news.

Man, the battle is not a big one.

This is the first furnace of molten iron in the base area. It is of great significance and everyone is here to witness it.

At 10:30 in the evening, it was time to officially tap the molten iron.

Below the blast furnace, four workers carried a crucible capable of holding 150 kilograms of molten iron like a sedan to the taphole and waited. There were three such teams behind them.

At this moment, everyone is paying attention.

When the first group of foundry teams was ready, an old worker came to the taphole below the blast furnace and used a steel drill to open the mud seal. In an instant, orange-red molten iron like magma suddenly gushes out and enters everyone's sight.

The groove flows down into the crucible below.

"Bah, bang, bang!" Seeing the orange-red molten iron flowing into the crucible, everyone at the scene applauded and applauded in unison.

There is no doubt that this is a historic moment, symbolizing the base area's restoration of pig iron production capacity.

Not long after, the first pot of molten iron was filled. Four casters carefully lifted the 150 kilograms of molten iron out of the blast furnace and headed for the pouring area. The second group of casters caught up and tried not to waste any drop of molten iron.

When they came to the pouring area, the first group of casters picked out the slag floating on the surface, and then the factory director Ma Tian, ​​who was standing aside, dropped a portion of powdered ferrosilicon into the molten iron in the crucible according to the prearranged arrangement, and carried out the incubation process to create artificial iron.

Crystal nucleus.

This was a standard ratio accurately calculated by Yu Hua. Although Martin didn't know why he put in ferrosilicon, he still carried out the order.

After stirring, in the microscopic world, the high-temperature molten iron reacts under the action of ferrosilicon, producing fine artificial crystal nuclei and precipitating graphite.

After adding the inoculant, the factory director Martin retreated to a safe distance, and the first group of four casters tilted the crucible mouth, aimed it at the water inlet of the mandrel sand mold, and poured out the molten iron.

"Squeak!" The fiery red molten iron was like a faucet, continuously flowing into the mandrel sand mold. In an instant, the sand mold made a sound like frying, and flames burst out from inside.

Fortunately, no explosion occurred.

After the first mandrel sand mold was poured, the second mandrel was poured immediately. The two mandrels were not heavy, adding up to more than 40 kilograms. The remaining about 100 kilograms of molten iron in the first pot were used to pour the roller sand mold.

The four roller sand molds are among the largest consumers of molten iron, requiring a total of more than 800 kilograms of molten iron.

Under everyone's gaze, four teams of casters worked back and forth, pouring hot molten iron added with ferrosilicon into the roller sand mold.

After more than twenty minutes, all the roller sand molds were poured, and next came the most important cooling and solidification stage of smelting gray cast iron.

To obtain gray cast iron, the first is the inoculant, and the second is the cooling time. The temperature cannot drop too fast during the cooling and solidification stage, otherwise graphite cannot be precipitated.

If necessary, the casting needs to be taken out of the sand mold and placed in a hot sand pit with a temperature above 500 degrees Celsius, or slowly cooled near a hot furnace.

Yu Hua and Lin Wan entered the pouring area, surrounded the six sand molds, and carefully recorded data such as pouring time and pouring performance.

"The mandrel cooling time is one and a half hours, and the roll cooling time is five and a half hours. At this time, the mold can be demolded. Jin Yu, please record it." After Lin Wan finished recording the basic data of each sand mold, Yu Hua then based on the casting cooling experience

Formula to calculate the approximate cooling time.

"Okay." Lin Wan nodded, holding a pencil in her right hand and writing down the cooling time data on her notebook.

Compared with workers’ accumulated subjective experience over time, smelting gray cast iron requires more systematic statistics and analysis to obtain corresponding metallurgical data.

"Deputy leader Yu, how long does it take for the grenade casing to cool down?" At this time, Zhao Shu, the engineering section chief who was standing nearby and observing, asked: "The arsenal is preparing to pour the grenade casing."

"Chief Zhao, the grenade shell can be demoulded in 15 minutes. When it naturally cools to normal temperature, gray cast iron can be obtained." Yu Hua replied with a smile: "Remember to add ferrosilicon."

Fifteen minutes...

Zhao Shu nodded, turned and left.

Soon, four groups of casters began pouring grenade shells. In addition to six sand molds, a thousand prepared grenade shell sand molds were placed in the pouring area, divided into ten batches.

Lot of one hundred grenades.

Under the cover of night, the pouring operation of the iron factory started again. Different from the previous pouring machine parts, this time it was military production.

Hot and red molten iron was poured into the sand molds of the grenade shells one by one. In an instant, the sand was ignited like a candle, emitting orange-red flames.

The foundry team was responsible for pouring molten iron. Zhao Shu and Hu Zhigang, as technical cadres, followed Yu Hua's method to record the pouring time of each batch of grenade shell sand molds, and then marked the scheduled cooling time.
To be continued...