I am the prince of the Ming Dynasty, I don't give up

Chapter 56 The Difficulty of Steelmaking
The carbon flowers in the molten iron began to become sparse. Zhu Houxuan knew that the remaining carbon element in the molten iron was beginning to approach the content of steel. He ordered his men to raise and lower the furnace rod once or twice to see if there would be more carbon flowers bursting out. When he saw that the carbon flowers did not increase suddenly, he ordered to stop the wind.

For a moment, all the donkeys in the yard stopped. There was no other way. Without a steam engine or water power, the blowing still mainly relied on animal and human power.

Afterwards, the craftsmen opened the bottom of the furnace, began to remove the slag and finally poured it. The bright red molten steel was poured into the molding sand, which was made of 90% yellow sand, 5% clay and 5% white mud.

After pouring and molding, it becomes a steel ingot. As for whether the steel ingot is high carbon, medium carbon or low carbon, Zhu Houxuan cannot control it now, and even has no way to measure it. He can only test the performance of the steel ingot.

"The quality of the steel ingots produced by this furnace, Your Highness, is better than the hundred-refined steel, and the output is really scary. It's the first time I've seen so much steel produced in one furnace! And this kind of steel is much more labor-saving than the hundred-refined steel." Jin Tong said excitedly.

In modern life, iron is our most common metal. It is everywhere and the price of iron is very cheap. However, iron was still relatively precious in ancient times and its price was much higher than it is today.

During the Tang Dynasty, the price of iron was about 400 times that of today, while during the Ming Dynasty, the price of iron was about 100 times that of today.

This is why iron is sometimes used as currency.

Not to mention steel, the open-hearth furnace made by Zhu Houxuan can produce nearly 5 tons of steel at a time, and it is a smaller version of the open-hearth furnace.

Open-hearth steelmaking not only has great strategic significance in the Ming Dynasty today, but also has huge economic benefits, which cannot be compared with cloth or something else.

At that time in the Ming Dynasty, the price of raw iron (pig iron) including freight was 0.9 taels of silver per hundred catties, or 0.009 taels of silver per catty.

Pig iron becomes wrought iron after being hammered and forged. Each round of hammering is called a fire/refining, which is almost a working day for a blacksmith. In addition to consuming labor and fuel, the iron will also be oxidized and lost during the forging process. Each refining costs about 0.03 taels per catty.

In the process of hammering, 30% of the wrought iron used by ordinary civilians is removed, that is, 7 catties of wrought iron can be produced from 10 kg of pig iron. If recycled scrap iron is used, 9 kg of wrought iron can be produced from 10 catties of scrap iron. However, this kind of wrought iron is not good enough for making weapons and armor.

After five times of hammering (five fires), only three pounds of wrought iron remain from ten pounds of pig iron, and the total cost of labor, materials and silver is 0.5 taels. The cost of wrought iron per pound is 0.166 taels, which is nearly 20 times that of pig iron. Among them, labor costs account for 50%, charcoal prices account for 32%, and pig iron costs account for only 18%.

This kind of five-fire wrought iron is the entry-level military iron material. On this basis, it can be further forged to obtain refined iron or steel (the definition of steel in ancient times is different from that in modern industry).

0.2 taels of silver per pound of refined iron/steel can be used to make armor. 0.27 taels of silver per pound of ten-refined steel (ten-fire) can be used to make the barrel of a bird gun. Each pound of this steel consumes five pounds of pig iron.

The hundred-fold tempered steel, which cost 3 taels of silver per pound, could be used to make swords. This cost was more than 300 times the price of the original pig iron. If this kind of steel was used to make armor, it would be the so-called wart armor. The material alone would cost more than taels of silver, and ordinary officers and soldiers could not afford it.

In ancient times, the only way to obtain high-quality steel was to repeatedly hot forge. Stir-frying and pouring steel cannot directly produce steel. Its value lies in converting pig iron into forgeable iron, thus reducing the production cost of steel.

It was so difficult to obtain steel in ancient times. At that time, the annual steel output of the Ming Dynasty was estimated to be equivalent to the steel produced by a night shift of a large or medium-sized steel plant in modern times.

If Zhu Houxun's furnace of steel is calculated according to the current price of hundred-fold-refined steel, it would be worth thirty thousand taels of silver. This is because the open-hearth steelmaking technology far exceeded the smelting level of that era.

In comparison, the textile factory only made hard-earned money. Of course, Zhu Houxuan also invested 70,000 to 80,000 taels of silver in order to develop this open-hearth steelmaking.

This is the charm of heavy industry, high investment and high returns.

"Done!" Zhu Houxuan held up a steel ingot and shouted to the craftsmen present.

Dozens of craftsmen present cheered immediately. It had been two months, two months since they had worked on this alchemy furnace. It had been opened more than twenty times, and finally there was a result.

Zhu Houxuan's open-hearth furnace was successful but not completely successful, at least he had not yet fully figured out the phosphorus removal step. Although he used the knowledge in his mind to make an alkaline lining for the open-hearth furnace, the phosphorus removal effect was unsatisfactory. Finally, Zhu Houxuan was forced to decide to change his path and give full play to the advantages of Daye Iron Mine.

There is a reason why Daye Iron Mine has been mined since the Three Kingdoms period and later became the main iron ore supplier for the Hanyang Iron Works during the Qing Dynasty's Westernization Movement.

In addition to being close to the Yangtze River and having convenient transportation, Daye Iron Mine's average iron content of 58% is truly unrivaled among most iron ores in China. It should be noted that most of China's iron ores are lean iron ores with an average iron content of more than 30%, while the iron content of iron ore imported from Brazil and Australia after the 21st century is above 65%.

The most important thing is that the iron ore of Daye Iron Mine is mainly hematite, which is characterized by low phosphorus content. Since the phosphorus removal effect is poor, the problem should be solved from the source.

This is also the reason why Zhu Houxuan was able to produce steel using a open-hearth furnace in just two months.

Now Zhu Houxuan didn't even need to keep the open-hearth furnace secret, because most of China's iron ore had a high phosphorus content. Even if someone else learned the technique, without the supply of Daye's low-phosphorus iron ore, the quality of the steel produced would be very poor.

Although there was a method to produce steel in large quantities cheaply, it was still a difficult problem for Zhu Houxuan to promote the open-hearth steelmaking method, because he was completely forcing things to happen, and the quality of his personnel was completely out of date.

Moreover, Zhu Houxuan did not have a way to accurately measure the temperature of molten steel. Steelmaking is all about temperature. If it is too high, the steel will overheat and be ruined. If it is too low, it cannot be smelted. Modern times rely on a bunch of high-tech sensors for timely control, and the success rate is very high. His success rate is not that high now.

This is why basic science has not caught up.

Therefore, Zhu Houxuan still has a long way to go in steelmaking.

However, it is still worth celebrating that he was able to develop this technology. At least he has trained Master Luo.

"Has the prince refined the elixir?" A haunting voice appeared, and the cheers of the surrounding craftsmen came to an abrupt end.

The person who came was Shi Changshi, who was curiously examining the steel ingots on the ground.

"Shi Changshi, why are you here?" Zhu Houxuan said with a bad look on his face.

"I just happened to be passing by and heard the craftsmen cheering. I thought the prince had made a magic pill, so I came in to check it out and learn something new. Did the prince make a magic pill?"

"No, but it's almost done. We still need to keep working hard. I will inform Shi Changshi when the elixir is refined," Zhu Houxuan said lightly.

"I have been looking forward to this day, so I will take my leave now." Shi Changshi tactfully said goodbye and left, but he was still observing as he left.

Watching Shi Changshi's figure disappear in the distance, Zhu Houxuan waved to Qin Ming, and Qin Ming hurried over.

"Have the people who went to investigate Shi Changshi returned?" Zhu Houxuan said in a low voice.

"Not yet, but it will be soon," Qin Ming said in a low voice.

"Well, we need to hurry up on this matter!"

(End of this chapter)