At this moment, an entourage quietly squeezed to Du Zhongxiao's side and whispered: "The official, the stranger who competes with others is the merchant who wants to sell us iron." I heard that he was fond of treasure knives and showed off his own knives on the ship, so he provoked this incident. ”

When Du Zhongxiao heard this, he hurriedly pulled this entourage aside and asked him to tell him in detail what he had heard.

Peng Xinshu, a merchant who came from Yingtianfu to sell iron, was in the iron business and loved to collect treasure knives. Everywhere you go, you must ask if there is any good sword, and if it is valuable, you buy it back. Of course, he buys and sells both, which is equivalent to a business. It's just that in this era, most of the good knives are military weapons, and there are no good knives among the people, and the price is high. Compared with Peng Xinshu's knife, Du Zhongxiao looks a bit like a weapon of the forbidden army, and the official cost is more than five times. It has undergone a makeover to the people, and it is not too outrageous to sell dozens of pieces.

After listening to the report of his entourage, Du Zhongxiao had a whim, if he made a batch of good knives and sold them to Peng Xinshu, he didn't know if he could exchange them for the money he urgently needed now. The key to a good knife is steel, which is readily available in the blacksmith county. Du Zhongxiao had done it in the factory in his previous life, and he was not familiar with other steels, but he still had a general understanding of high-carbon tool steel. Tool steel is an excellent material for making swords, and with qualified quenching and cutting edges, it can outperform most swords of this era. Mass-produced things don't need to be compared with the top swords, and weapons that are stronger than the forbidden army are enough to sell for a good price.

Du Zhongxiao happens to know how to make high-carbon tool steel under the current technical conditions.

In the previous life, I took a class on metal materials, but unfortunately the blast furnaces, open hearths, converters, etc. in iron and steel metallurgy were too complicated, and Du Zhongxiao had long forgotten the specific process, only remembering the name. But there is one of the easiest methods, crucible steelmaking, Du Zhongxiao remembers. This method is simple, as long as you remember a rough approximation, it can be restored, and the scale is small, suitable for small places at the county level. In fact, this method is Du Zhongxiao's soil method of steelmaking in his previous life.

Steel is difficult to smelt because the high carbon content in iron will reduce its melting point, and iron can only be smelted into raw iron. After the decarburization of pig iron, the carbon content is too low to become wrought iron, and the carbon content of steel is between pig iron and wrought iron. Of course, there is another reason, when the carbon content is low, the melting point of iron increases, and ordinary ironmaking furnaces cannot reach the temperature to melt it completely. This is the basic principle of steel, Du Zhongxiao still remembers.

At this time, the so-called treasure knife generally refers to the hundred steel knife, which is made of wrought iron after many carburizing forging, which takes a long time and has a high cost. Of course, this method cannot be used for standard steel knives in the army, and most of them use fried steel. Because the fried steel is molten pig iron, it seeps into the semi-molten iron, the material is uneven, and the quality is not as good as that of a hundred steelmaking knives. And if you use a crucible to make steel, the material is uniform, and it can be compared with a hundred steel knives.

The crucible should be made of graphite. One is that it is resistant to high temperatures, which can melt the steel inside, and the other is that the composition of graphite is carbon, which will not lose carbon and become wrought iron in the process of steelmaking. Knowing the basic principles, the process of steelmaking can actually be roughly deduced.

When Du Zhongxiao was sitting under the tree and thinking, Chai Xin came over with excitement on his face.

After saluting, Chai Xin said: "The two good knives at the end are sharpened like clay!" The three copper coins were stacked up, and they were also broken with a knife. It's just that the two of them cherish the treasure knife, and they don't compare it, and the stranger spent fifty yuan to buy another person's knife. ”

Du Zhongxiao said with a smile: "What kind of cutting copper coins is cutting iron like mud." You go back to practice, borrow the knife of the master of Yao Zhai, and you can also cut a few copper coins. ”

Seeing Chai Xin's look of disbelief, Du Zhongxiao didn't explain to him, and the explanation was not clear. People in this era do not have a rational understanding of the hardness and strength of metal, so they will take copper coins to test knives.

When Dong Zhushu came back, Du Zhongxiao said: "Master, we are talking in the tea shop over there." ”

When the two arrived at the tea shop next to the wharf, they saw a mountain-like pile of reed mats outside the shop that was expected to sell groceries not far away, Du Zhongxiao said with a smile: "These business people are very attentive, and they have received a lot of reed mats, and they are not afraid of running out of goods when they open." ”

Dong Zhushu said: "According to the county charter, these are all industries that make money for the county officials, how can they not care." ”

Du Zhongxiao shook his head, knowing that what Dong Zhushu said was the truth. The public servants are much more attentive to doing things for themselves than for the yamen. There is no way to do this, for most of the public to do things for the yamen is not even a job, just an errand, where will they do their best.

After drinking a bowl of tea, Du Zhongxiao said to Dong Zhushu: "Master, I have thought of a way to make money, which can fill the hole in the payment, but I just want the master bookkeeper to take a trip." The merchant who bought the knife there just now was a rich man. ”

Dong Zhushu said: "If I can make money, why don't I break my leg!" I just don't know what to do? What are the ways to make money? ”

"The merchants who sell iron over there like to buy treasure knives the most. The chief bookkeeper went and told him that if I had a good knife here, much stronger than the one he had just bought, would he buy it? If it's fifty yuan, you only need to sell him for twenty yuan. ”

Hearing this, Dong Zhushu was taken aback: "Zhixian, that kind of good knife can be regarded as a weapon, is it inappropriate to sell it to the people like this?" ”

Du Zhongxiao waved his hand: "The imperial court can't help swords, what is it to sell a few knives, where can't he buy them if he has money?" It's important to make money. ”

Seeing that Dong Zhushu was still not at ease, Du Zhongxiao said again: "If you have the intention to do evil, why use a knife." He was an iron merchant, and he found a blacksmith to make dozens of large axes, which were no better than knives. Besides, if you want to kill someone, it's the same as a bad knife, and a good knife is just sold to the rich to play with. ”

Du Zhongxiao can think about this kind of thing, a knife is a knife, and a good knife will not do more bad things than a bad knife. The use of the army, because it involves wear and tear and repair, naturally it is necessary to use a good knife, and the difference between ordinary people with swords is not so big. Twenty or thirty knives can be made in many blacksmith shops, so why not sell them yourself to make some money.

Dong Zhushu was worried about the payment, Du Zhongxiao said so, why did he insist? asked: "It's just for a while, where did Zhixian find so many good knives?" Even in the inspection village, those knives are also useless in the forbidden army, and they can't be sold if they want to. ”

Du Zhongxiao said with a smile: "I have my own way to refine a batch of good steel, and the master book will let the merchants wait for a few days." ”

"The magistrate will also make steel?" Dong Zhushu felt strange, as the magistrate of the county, he still knew all kinds of miscellaneous studies.

Du Zhongxiao didn't say much, and only asked Dong Zhushu to arrange it. The most important thing in crucible steelmaking is to make graphite crucibles, but fortunately, because I want to make drawing pencils, I have accumulated some in the county. Everything went well, and in three to five days enough steel could be made. Another point in steelmaking is that the furnace temperature must be high enough, and once the temperature is not enough, a pile of scrap iron will come out. Designing a furnace is also a difficult point. Traditionally, coke should be used as fuel, but now it is too late for coking, so coal has to be used, and it must be tested.

After discussing with Dong Zhushu and asking him to negotiate with the merchants, Du Zhongxiao took Chai Xin and returned to the county all the way.

Back in the study, Du Zhongxiao sorted out the things that needed to be done, and said to Chai Xin: "You go to find Wang Zhisi, and ask him to find a few skilled blacksmiths from the county and go to the yamen to listen to orders." Then go find ten skilled masons, I'll be useful here. ”

Chai Xin was shocked by the two treasure knives he saw today, and he still has a good aftertaste. The fork hand promised, and before going out, he couldn't help but ask: "Official, is there really a way to refine good steel and make the treasure knife you saw today?" If it were so easy, wouldn't the sword be worthless? ”

Du Zhongxiao shook his head: "What words!" Even if it is built, this knife is also valuable, otherwise why would it sell for dozens of pieces? ”