Looking at the small furnace of steelmaking, Su Song said: "I never thought that when frying steel, you don't need to burn charcoal, just blow the air." Who can believe it if they don't really try it? Everything in the world has its own natural reason, and without detailed scrutiny, I dare not make assertions. ”

Du Zhongxiao nodded. In the past, when I was in Yongcheng, the scale of frying steel was small, and the most common method of this era was used. A few days ago, a steel furnace was built here, and in order to make full use of energy, it was naturally built next to the smelting furnace, and the steel and ironmaking were connected together. The molten iron that comes out of the smelter is directly fed into the frying furnace, so that a lot of fuel is used.

The principle of frying steel is still clear to Du Zhongxiao. It is nothing more than that the iron is smelted in a reducing atmosphere, so that the carbon content of the molten iron is too high, and what comes out is pig iron. When it comes to the frying furnace, to reduce the carbon content, there is no charcoal in the furnace, only limestone and dolomite and other slag agents are added, which is heated indirectly rather than directly, and is under an oxidizing atmosphere. Since it is an oxidizing atmosphere, oxygen should be sufficient, otherwise the effect is not good.

This is what chemistry is about in middle school, and it's very simple. In order to ensure sufficient oxygen, the steel frying furnace built here is specially equipped with a blowpipe, and there is also a large bellows to blow air inside. Unexpectedly, the molten iron in the steel furnace boiled rapidly, like a volcanic eruption, and the temperature was obviously much higher than the charcoal burned underneath before. Because it is difficult to control, the charcoal fire below is constantly reduced, and the result is still not obvious. In the end, the charcoal is not burned when the steel is simply fried, and the temperature in the furnace is high enough to reduce the carbon content of the molten iron and make steel.

Du Zhongxiao wondered for a while, and finally could only think that it was the charcoal in the molten iron, or some other elements, which were blown into the air in a high-temperature melting state, and an exothermic reaction quickly occurred, keeping the molten iron boiling. This is actually the later generation of oxygen blowing steelmaking, whether it is a converter or an open hearth furnace is the same principle.

After the blast, because the molten iron boiled violently, in order to control the reaction speed, I tried to add pig iron and scrap steel to it, and accidentally found that the steel properties were different at different temperatures. Different tapping temperatures will smelt steel with different carbon content.

It's a delicate job. Neither the temperature nor the precise control of the time can be controlled, and the state of the molten iron and the color of the molten iron can only be observed with the naked eye to control different steels. Du Zhongxiao tested a lot of people to do this work. Constantly training, now there are about twenty outsiders barely finding the state, it is the baby bump here in steelmaking. They're just getting started now, and the steel that comes out is unstable, but it's enough for this era. Anyway, what comes out is medium and low carbon steel, and the ability to build a sword is enough, and it depends on the craftsmanship of craftsmen.

Is it possible to measure the temperature as accurately as possible? In fact, there are still solutions. For example, gold, silver, copper, iron and other metals, or some already known compounds, make test pieces, use their different melting temperatures, put them into molten iron to detect, and see the degree of melting to determine the steelmaking process. It's just that this work is delicate and complex, and Du Zhongxiao can only provide an idea for the people below to do, which can't be done in a short period of time.

Temperature measurement does not necessarily use a thermometer, and some special physical and chemical reactions, such as melting and boiling, such as decomposition and compounding, can obtain a fixed temperature. However, it takes a lot of practice to choose the right measurement substance and the right measurement method.

High-carbon tool steel still cannot be refined with this kind of furnace, but try to smelt iron with low carbon content, and use a graphite crucible furnace to refine it with pig iron. This kind of high-performance steel refining is not easy to make, and the performance is superior, which is not comparable to the big road goods from the frying furnace.

With the method of blowing air, the efficiency of frying steel has been improved a lot, and the smelting of a furnace of steel is far faster than the previous charcoal burning. This incident made Su Song feel novel, obviously the cost of not using fuel has been reduced, and the efficiency is still greatly improved, and the things in the world are really magical. He spent a lot of time researching, and finally could only agree with Du Zhongxiao's statement. There is carbon in pig iron, and there is no excess carbon protection in the steel frying furnace, and this carbon is burned.

The actual chemical process is of course much more complex than this, carbon also forms carbon monoxide, and then carbon dioxide, and the excess carbon forms a reducing atmosphere. Once there is an excess of oxygen, the carbon in the molten iron continues to oxidize, reducing the carbon content and turning the pig iron into steel.

From ironmaking to steelmaking, it is such a simple process, and if you study it carefully, you can actually open the road to chemistry.

There are so many things that Du Zhongxiao has to do, and it is impossible for each industry to study in depth, even if he knows what is going on, he does not have the energy to systematically summarize it. The talents in this iron prison don't know who it will be in the future and when it will be able to open this door.

The principle is very important, knowing the principle, can be actively applied to practice, the knowledge of mathematics, physics and chemistry in middle school is enough to open the door of the industrial revolution. The economic strength of the Great Song Dynasty is the first in the world, this is the official iron prison directly under the jurisdiction of the imperial court, and there is Du Zhongxiao, a person with knowledge of later generations, and the conditions are many times better than those small workshops in Britain back then. From steel to machinery, the development of industry is much easier than in history.

It takes much less time than molten iron to come out of the furnace, and it doesn't take much time for the first furnace of steel to be completed. I saw that the small furnace was dumped, and the molten steel flowed out of it and into the cooling pool that had been built next to it. After a little cooling, it was scooped into the casting model by the workers on the side, and it became a steel ingot. Most of the ingots are transported to the next process when they are not solidified, and they are not far away from the forging area.

A small river nearby has already been cut off and a small reservoir has been built, and the river water is brought here to drive the hammer. The forging worker observes the color of the steel, takes it to the forging hammer and forges it.

The steel fried in this way is limited by the process, there are many pores in it, and there will be a small amount of impurities, which cannot be directly manufactured into utensils, and must be forged before it can be. Huge forging hammers are struck on steel ingots of different sizes, red or white, and with the steel molds that have already been made, some of them become steel bars, and some are beaten to extremely flattened, and when they are red-hot, they are sent to the rolls behind and slowly rolled into steel plates. In this way, it is a hot-rolled steel plate.

Chi Hao under the blast furnace was already stunned, he couldn't believe his eyes, he couldn't imagine that iron smelting would be like this. Looking at the blast furnace over there, the conveyor belt does not stop for a moment, does not stop the ground, and every once in a while, it opens to draw out molten iron. After the molten iron comes out and the condition in the furnace is stable, there will be no interruption in the feeding, so that the iron will be continuously produced for ten months.

Seeing that everything was going well, Du Zhongxiao breathed a sigh of relief. In fact, I am a little greedy and pursue efficiency too much. The preparation time is so long, in addition to the difficulty of building the blast furnace, there are too many subsequent processes, and it takes too much time from making tools to cultivating talents. Regardless of iron smelting and steelmaking, the products of this era are actually steel ingots and iron ingots, but Du Zhongxiao wants to directly produce profiles. The final products of this iron supervisor are mainly steel bars and steel plates. As for the most common round steel bar in later generations, because it was somewhat difficult to forge, there was none, only square square square steel bar.

Such a process, although complex, greatly improves efficiency and also reduces fuel consumption. If the ingots are tapped, they will be burned red and forged in the future, which wastes fuel in vain. This is the same as the fact that the frying furnace is built next to the iron smelting furnace and does not have to be reheated.

Seeing the stunned look of Chi Hao beside him, Du Zhongxiao felt a sense of accomplishment, and said with a smile: "Palace, let's go to the back and see the iron piece you want." If it suits you, you'll start making it. ”

"Okay, okay, go and watch with the judge." Ji Hao, who was shocked, nodded again and again, and his words were not good.

Walking through the forging hammers one by one, when you reach the rear, you can see several rows of steel rollers. The forged steel plates are fed into the steel rollers, which are sent down in turn, and are pressed thinner and thinner each time, and finally become a steel plate. The number of pressures is different, the gap between the steel rollers is different, and the thickness of the steel plate is different.

These steel rollers are also driven by water power, and only workers inspect back and forth, which is much quieter than the place where the steel is made.

When he arrived at the farthest row of steel rollers, Du Zhongxiao pointed to the steel plate on the ground and said, "Palace, is it agreeable to be so thick?" ”

Chi Hao saw that the steel plate was evenly thick, slightly glowing with blue, and couldn't help bending down to look at it.

The workers on the side saw it and hurriedly shouted: "No, be careful of burning your hands!" ”

Before the words fell, Chi Hao screamed and jumped up. Looking at the hands again, there are already a few blisters burned.

The workers over there looked at Du Zhongxiao, frightened for a while, and speechless.

Du Zhongxiao waved his hand, motioned for him to do his own work, and said to Chi Hao: "Palace attendant, this iron plate will come out, you can't touch it!" ”

Ji Hao nodded, covered his hands, and didn't know what to say for a while. Fortunately, the temperature of the steel plate is not particularly high, but it is just a blister, and the fingers are not burned, otherwise it will become an iron plate.

Pinching his fingers, Chi Hao said, "Yun Juan, it's good enough to be thick like this." But we have to dip iron sheets into copper, and it is better if we cut them. ”

Du Zhongxiao said: "This is easy. There is a cutting machine in the back, and you can cut what you want. In fact, it is easier for you to transport the iron plate back directly, we will send you a few large iron scissors, and go back to cut it yourself. ”

Chi Hao said: "Then I will take half of everything, after I transport it back to the copper prison, I will see what the supervisor means, and I will do it in the future." ”

The price of iron pieces is much more expensive than money. According to the current process, it is annealed first, and after the pig iron can be forged, it is forged. Not to mention the cost of fuel and labor, after hammering into iron sheets, at least half or even more is lost. After seeing the production process here, Chi Hao knew that there would be no cheaper iron pieces in the world than here. In the future, the iron used by the copper supervisor will probably be purchased from here. Although the road is farther, firstly, there is less railway in the south of the Yangtze River, and secondly, it is cheaper than hammering it by yourself with freight.