Shi Yiwen, who was frowning, listened to Zhao Shizhen's question and asked back.

"Look at what is the most expensive among bird guns?"

“What’s the most expensive?”

Zhao Shizhen thought for a moment, then said.

"It should be a gun barrel. The gun barrel has been working in the first place since the embryo refining, rolling, drilling the gun heart, and grinding, accounting for two-thirds of the work. Its labor cost is the most expensive."

While surprised by Zhao Shizhen's memory, Shi Yiwen nodded.

"Yes, the most expensive and time-consuming thing is the barrel. It doesn't matter if you offer a price of four taels of silver. The most important thing is how to reduce the cost. This is the most important thing, and how to reduce the cost of the barrel is the key factor."

"Young Master, this cost is probably not easy to reduce. After all, this barrel is the foundation of the flintlock rifle."

"That's right, if you want to reduce work on this, you will probably not lose anything."

Listening to the persuasion of the two of them, Shi Yiwen shook his head and said,

"I'm not talking about cutting corners. In this way, everyone should rest first today, and wait until I figure it out, and we will continue tomorrow."

Some things must be difficult to understand by just thinking about them. In the end, Shi Yiwen went to Zhang Sixi to learn about the entire process of making bird guns from his detailed knowledge.

"So, the function of refining embryos and hitting the plate is to make the pig iron mature? "

"Yes, young master, the iron courses collected by the Ministry of Works are all pig iron. You must first make mature iron and then make a plate before you can roll it into a gun barrel."

“No wonder the labor costs are so high.”

"Yes, young master, even if you have made it into mature iron, you have to beat it into a board with one hammer. People say that it is easy for craftsmen to make money, but it only makes hard money."

"Actually, it doesn't have to be so hard."

"Young Master, what did you say?"

"Nothing, let's continue talking."

Continuing to chat with Zhang Sixi, Shi Yiwen basically had an understanding of the manufacturing of bird guns, and of course he also knew where to start.

Because the New Year is approaching, Shi Yiwen did not leave Zhang Sixi. When he asked him to return to Beijing, he specifically told him to reassure him that even if he used them, he would pay according to the work.

Shi Yiwen never disdains to take advantage of things.

"That day, you said that cutting corners is absolutely impossible to do. In fact, compared to cutting corners, you can completely reduce costs by technology."

Facing Zhao Shizhen and Wu Cai, Shi Yiwen said with a smile.

"technology?"

"Yes, it's the technology. Look, this embryo refining requires six labors, which cost about two cents of silver. The purpose of embryo refining and plate making is to make pig iron mature iron plates. Since we have an iron factory now, we can start with iron refining and make mature iron plates directly."

Shi Yiwen explained.

"Make mature iron plates directly?"

"Yes, it's just to refine the iron."

Zhao Shizhen said in surprise, he had only heard of Gu Qian getting ripe iron after he had tempered it, and he had heard of smelting iron directly.

"Actually, this is nothing more than building a new stove."

Turning his eyes to the two iron smelting furnaces with a daily output of 1,000 kilograms in the iron factory, another idea emerged in Shi Yiwen's mind. With these earth furnaces, it will be overwhelming in a year, which is only 200,000 kilograms of iron. Such a small amount of iron is not enough to make a flintlock rifle.

"Shiji, didn't you say that I want to show my skills that day? It's just right. Since we want to do this, let's start from scratch, dismantle the two stoves first, and replace them with a new stove!"

He did it right away. In everyone's surprise, the two iron smelting furnaces in the factory stopped working. Then Shi Yiwen took out a new blast furnace drawing. In fact, the blast furnace drawings found in the library were not the 1.5 cubic earth blast furnace common in the era of large steelmaking. It is a blast furnace that is more than seven meters high and made of bricks and stone. Its reference is the general structure of modern European large blast furnaces and modern air blast furnaces. It can produce twenty tons of pig iron every day. It also needs a bellows connected to hydraulic power.

He did it as he said, and for the end of the year, Shi Yiwen stayed in the iron factory and was busy building a new blast furnace. However, the construction of the furnace was not simple. When the masons used stones from the mountain to penetrate the furnace, the most critical refractory materials also needed to be solved. Because smelting steel requires a temperature of about 1500 degrees, ordinary clay bricks will begin to soften at around 1400 degrees, so refractory bricks must be fired.

In fact, it is not too difficult to fire refractory clay bricks. Ordinary land tiles kilns can do it. However, even so, Shi Yiwen has been "barriering" with the bricks in the next two months.

Just when the sixth year of Wanli was about to be over, the first batch of refractory bricks were burned in a trough-type earth kiln with a length of 4 meters, a width of 2 meters and a height of 2 meters for three days, and then cooled for another two days. Finally, after leaving the kiln, Zhao Shizhen, who was already a little impatient, asked.

"Zhiyuan, are you talking about the refractory bricks laid in the furnace?"

Facing his inquiry, Shi Yiwen said dullly.

"No, this is a brick kiln."

"We still need to build a brick kiln?"

"right!"

Shi Yiwen's tone was a little helpless. The main components of this batch of refractory bricks are made of clay, including aluminum trioxide and silica. Although this refractory brick can withstand high temperatures of 1730 degrees, it is not suitable for use as a blast furnace and can only be used in hot air furnaces. Because alumina and silica are acidic materials, they will react with reducing agents and slag during the smelting process, so another brick kiln is also needed to be built - firing alkaline refractory materials.

The alkaline refractory materials in the 21st century are generally made of magnesium oxide pressing, and electrolytic technology is required to make magnesium oxide... This is of course an unattainable material. In the book "Civilized Iron Smelting", the road to solving the problem is also pointed out - dolomite bricks. The written statement is tar dolomite bricks. Dolomite is a relatively common stone, and there are such stones on the mountains near the iron plant. Dolomite is a composite of calcium carbonate and magnesium carbonate. Calcining can obtain heat-resistant alkaline materials calcium oxide and magnesium oxide, while tar asphalt is a binding agent.

However, because the calcination temperature of tar dolomite bricks is between 1600 and 1650 degrees, which is far higher than the refractory degree of ordinary clay bricks, it is necessary to achieve the firing of refractory clay bricks to build brick kilns for firing dolomite refractory bricks.

It took about two months before and after, until February 20, the seventh year of Wanli, Shi Yiwen finally got the tar dolomite refractory bricks he needed for the furnace. The asphalt in the raw material of the tar dolomite bricks was a by-product obtained through coking.

Finally, when the first batch of refractory bricks were spread out in the furnace of the blast furnace, Shi Yiwen, who had been busy for two months, finally realized what an industrial system is. Not to mention anything else, if he was poor and wasted, just such a brick would have taken his own life. But without this brick, there would be no blast furnace. Without blast furnace, there would be no large-scale steel industry.

In fact, in many cases, what restricts industrial development is these tiny seemingly insignificant things.

When the craftsmen were laying fire-resistant bricks, they seemed to suddenly think of something. Looking at the craftsmen, Shi Yiwen said to Wu Cai beside him.

"Wu Cai, do you know? I dare say that even in ten years, no one can imitate my iron factory!"

A sudden sentence, before Wu Cai could react, he heard the young master sigh again.

"You, I almost exhausted a brick. Can they make such a brick?"

They can't make it at all. After all, it seems like a simple stone is actually a reflection of the industrial system. They have been working hard for two months with textbooks. Others... without more than ten years, they can't see the mystery.
Chapter completed!