On May 25, Li Zhi looked at a dozen crucible craftsmen from Texas and handed over two stones. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 ｉｎｆｏ

In the past, Li Zhi had always asked Cai Huaishui to go to Texas to buy crucibles for burning glass and steelmaking. In fact, Li Zhi has become the number one customer of the Texas Crucible Craftsman.

This time, Li Zhi wanted to build a steelmaking converter, so he simply invited these people at a high price and asked them to come to Fanjiazhuang to build a converter lining for Li Zhi.

Over the years, Li Zhitian has received orders for crucibles, and these Texans have obviously become rich. At this time, more than a dozen craftsmen were dressed decently and ruddy, and at first glance they were people living a wealthy life.

The crucible craftsmen looked at the stone handed over by Li Zhi, pinched it, and said, "Grandpa Guo! This is dolomite and kaolinite! ”

When Li Zhi heard this old saying, he looked at these Texans with appreciation, and secretly said that this was worthy of being a craftsman who had produced countless steel-making crucibles for himself. In fact, in order to find relatively pure dolomite and kaolinite, Li Zhi spent a lot of work, specially hired more than 20 people to look for mines in Shandong, and searched for more than two years before finding them.

With these two materials, Li Zhi can make a qualified converter lining.

More than a dozen crucible craftsmen handed Li Zhi's two stones to look at, and they couldn't help but nod their heads in praise. Li Zhi's two stones are of high purity, and they are rare and good ores, which are very different from the ordinary ores that can be found in the mountains and wilderness.

Li Zhi and the other technicians all looked at the ore before saying, "I want you to use these two ores to make a large blast furnace lining for me." ”

After listening to Li Zhi's words, a Texas craftsman asked curiously: "Using kaolinite as a furnace lining, we understand that this kaolinite is very tough when it is hot, and it is a good material for making crucibles." But why use dolomite? ”

In fact, the so-called dolomite of the Ming people is calcium and magnesium carbonate. Although the ore is also resistant to high temperatures, it is rarer and more difficult to work with than kaolinite. The reason why Li Zhi wants to use this material and kaolinite together to make the converter lining is because magnesium oxide can withstand alkaline molten steel.

Phosphorus is one of the harmful impurities in steel. Steel with a high phosphorus content is prone to brittleness when used at room temperature or lower, which is called "cold brittleness". The higher the carbon content in the steel, the more severe the brittleness caused by phosphorus. Generally, the phosphorus content of ordinary steel is not more than 0.045%, and high-quality steel requires less phosphorus.

But there are very few of nature's iron ores that do not contain phosphorus. Correspondingly, the pig iron, a steelmaking material that Li Zhineng can buy on the market in Daming, must also contain a large amount of phosphorus. These phosphorus elements are dissolved in molten steel to form an alkaline environment. Only by using dolomite to make an alkaline lining can phosphorus be removed in the steelmaking process.

In 1856, Bessemer invented the acid converter steelmaking method. However, acid converter steelmaking cannot remove phosphorus. In 1879, Thomas invented the alkaline converter steelmaking method that could handle high-phosphorus molten iron, which made it possible to produce ordinary steel on a large scale in European countries. Li Zhi uses this alkaline converter method.

However, Li Zhi was not prepared to talk too much about this steelmaking knowledge with the new craftsmen, Li Zhi said lightly: "My steelmaking blast furnace needs such a lining, and you can use this dolomite and kaolinite to make a lining that can withstand high temperatures." ”

The crucible maker grabbed the dolomite for a while longer, and finally said, "We may also use some black talc in the lining of the furnace." ”

Li Zhi nodded and said, "Yes!" ”

With Li Zhi's permission, the crucible craftsmen went to the wagon to get tools and materials, and prepared to build a furnace in a factory provided by Li Zhi and fire the lining of the blast furnace. Li Zhi stood aside and looked at it, and saw that they had brought a lot of tools and materials, and there were five carriages.

"How long will it take for this converter wall to be made?"

The leading crucible craftsman touched his head and said, "I'm afraid it will take a month!" ”

Li Zhi nodded and said no more.

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Li Zhi gathered 30 craftsmen who had worked in the crucible steelmaking workshop for many years, and erected a blackboard in the workshop of the converter steel mill, where there was no equipment to settle in, to teach the craftsmen new steelmaking knowledge.

These 30 people are Li Zhi's new team that Li Zhi is preparing to use for converter steelmaking, and Li Zhi is ready to let them understand the principle of converter steelmaking, which will help them better smelt steel.

Li Zhi held up a piece of wrought iron and a piece of charcoal and said, "First of all, everyone needs to understand that there is carbon in iron. Wrought iron is iron with a very low carbon content, while pig iron is iron with a carbon content of more than 2%. And the carbon content is between wrought iron and pig iron, which we call steel. ”

The audience had heard Li Zhi say this truth a long time ago, but at this time they only heard it again.

"So there are naturally two ways to make steel, one is to increase the carbon content of wrought iron. The other is to reduce the carbon content of pig iron. Our converter steelmaking method uses the second method, which reduces the carbon content of pig iron. ”

"We use a blower to blow air from the top into the molten iron, and the carbon and impurities in the molten iron react with the air at high temperatures to produce carbon dioxide and other substances. Carbon dioxide is carried away with the air, while other impurities form slag along with our slag maker. ”

"When these impurities burn in the air, they emit a lot of heat, which will keep the entire molten iron in a boiling state. Therefore, the molten iron only needs to be heated once in the whole steelmaking process, and then the molten iron will always be in a state of high heat. At this time, adding calcium oxide and other slag forming agents to make slag can improve the quality of molten steel. ”

"The so-called slag making, everyone understands, in the final analysis, is the operation of adjusting the impurities in steel and iron. The aim is to turn impurities into slag, reduce sulfur and phosphorus below the upper limit of the planned steel grade, and minimize the amount of splashing and slag spillage when blowing oxygen. ”

These 30 steelmakers are all old workers in the crucible steelmaking workshop, and after listening to Li Zhi's words, they all basically understand the principle of converter steelmaking. Li Zhi finished saying a paragraph to see the audience's reaction, and the workers kept nodding their heads, indicating that they understood.

Li Zhi looked at his old workers and felt that he would not encounter too many problems in developing converter steelmaking. After all, his crucible steelmaking workshop has been in operation for so many years, and the workers have a set of ideas on how to manage the boiling molten iron and how to make slag. Li Zhi mentioned it a little, and these workers were able to draw inferences.

Li Zhi pressed a little harder with chalk on the blackboard, and finally said: "Of course, when the molten steel is at rest, the speed at which inclusions float up and remove is slower. Our blowers have limited wind power, and the blower blowing alone cannot make the reaction complete quickly. We have to use tools to stir the converter. So we need two steam engines for each converter. One is responsible for top blowing, and the other is responsible for stirring. ”