"Ignition!"

With Zhang Han's order, Li Shengzhong lit the oil-soaked linen cloth and pushed it into the hearth of the open hearth, and the linen quickly burned, igniting the coke laid in the furnace, and soon the furnace was red. Zhang Han felt a wave of heat rushing out of the observation mouth, and couldn't help but take a step.

As soon as Zhang Han dodged away, Zhang Tingfang couldn't wait to protect his face with his hands and came to the observation hole. Li Shengzhong couldn't grab the position, and turned sharply on the side. Zhang Han smiled and took a step back. It seems that they all attach great importance to it!

Now that open-hearth steelmaking began, graphite crucibles were of course manufactured.

Just after the New Year in the fourth year of Jianning (171), Li Shengzhong encountered an extremely important opportunity in his life. Because of his outstanding performance when he helped improve blast furnace ironmaking last year, this time to improve steelmaking, Zhang Han asked him by name.

Li Shengzhong is a native of Runan, he is a blacksmith, and his craftsmanship is also one of the best in the Zhang family. It is conceivable that Li Shengzhong is also a very famous blacksmith in his hometown. If it weren't for a catastrophe in the eighth year of Yanxi, Li Shengzhong would not have fallen to this point anyway.

Li Shengzhong is a proud man - people who are outstanding in some aspects have this kind of arrogance, but some people are on the outside and some are hidden on the inside - he has the craft, so he is not willing to live under others. Comparison is ubiquitous, the treatment between slaves is very different, and Wang Guanquan, who is equivalent to his craftsmanship, is the third generation of domestic slaves of the Zhang family, and he can't compare. However, Li Shengzhong is not only himself, but also his family and children, he can't be allowed not to work hard, he can't compare to his connections, he works hard.

Therefore, when he encountered this opportunity, Li Shengzhong did not hesitate and firmly grasped it. Thus, Li Shengzhong began a journey of defeat that lasted for one year and eight months.

The making of graphite crucibles is simple. One-third graphite, one-twentieth china clay, and 62 percent refractory clay are mixed evenly and then molded by hand on a turntable. Then, dry over low heat, and then burn with coke to the highest temperature.

"It's so easy!"

Li Shengzhong can do three in one moment.

However, graphite needs to be screened, refractory clay needs to be sanded, and porcelain clay must be coal-born china clay, which has to be calcined...... Everything had to be groped little by little from the first few words, and Li Shengzhong experienced 2,782 failures.

Failures, failures, and failures after failures, and those who have not tasted it cannot imagine what it is like. Li Shengzhong is not alone, he still has a wife and children, if he continues to fail, he will be finished......

The young master of the Zhang family is very good, he never urges him, he always says that he is not in a hurry, take his time, and success always has to experience failure first. However, there are fewer people who are slowing down......

In February of the first year of Xiping (172), under heavy ideological pressure, Li Shengzhong dedicated his secret secret.

At that time, ethnography was expanding greatly, and Zhang Han was busy and about to fly. finally finished his family studies, and began to write again, and then it was the New Year, Zhang Han hated not being able to grow eight hands, where could he take care of Li Shengzhong. Li Shengzhong didn't know this, thought about it, and took out the secret ruthlessly.

The Han Dynasty was a period of great development of China's iron and steel smelting. Steel quickly spread to all regions of the country. This steel refers to fried steel. Stir-frying means that after the pig iron is heated to a liquid and semi-liquid state, the metal is stirred with an iron rod to quickly decarburize it into steel.

It was an extremely advanced smelting technique, and it was not until the 18th century that Europe invented a similar technology. However, because the frying is usually carried out in a semi-liquid state, the impurities in it cannot be eliminated, and the quality of the steel is very poor.

Li Shengzhong's secret is in the smelting furnace.

At that time, charcoal and pig iron were used to smelt steel in a furnace. During the smelting process, the impurities in the charcoal will also enter the frying steel, further reducing the quality of the steel. Li Shengzhong divided the smelting furnace into two chambers, charcoal was placed in the lower chamber, the upper chamber was released with pig iron, the blast entered from the bottom of the lower chamber, and the flame entered from the upper part of the lower chamber and the bottom of the upper chamber. In this way, there are fewer impurities in the frying steel, and the quality of the steel is naturally better. However, due to the lack of carbon replenishment in the frying process, the craftsmanship of the craftsmen is more demanding. If you're not careful, it's easy to fry mature iron.

After seeing Li Shengzhong's operation, Zhang Han was very happy and praised him vigorously.

In fact, Zhang Han doesn't pay much attention to this 'secret that cannot be passed on', but just wants to reduce the burden on Li Shengzhong. He hoped to make high-quality steel as soon as possible, but he also knew that this matter could not be rushed. Even if Li Shengzhong immediately took out the crucible, it is still unknown whether he can use the crucible to refine high-quality steel.

However, this incident reminded Zhang Han that he could improve the existing process before open-hearth steelmaking was realized.

The difference between pig iron, steel, and wrought iron is the carbon content.

If the carbon content is more than 2%, it is pig iron; If the carbon content is less than 0.1%, it is wrought iron, and in the middle is steel. However, the Great Han Kingdom did not have this concept. Instead, the carbon content of less than 2% is commonly known as wrought iron. The one with better quality and strong sex is called steel.

Knowing this, Zhang Han easily deduced that the steel frying process is a process of rapid decarburization. The principle should be that agitation of the molten iron increases the contact between the carbon and the air, so that the carbon reacts quickly to produce carbon dioxide.

Understanding the principle, Zhang Han immediately found that cooling the pig iron into a block and then heating and frying the steel was completely taking off his pants and farting - Fei Na twice. After the molten iron comes out, fry the steel directly, and you won't get it. After thinking about it again, Zhang Han felt that it should be so, and there were no flaws.

The new method was soon put to trial.

When the blast furnace is finished smelting, the red-hot molten iron is discharged into a pre-built pond. The bottom of the pond slopes slightly outward, getting lower the farther you go. Two rows of people stand side by side on both sides of the pond, and after the molten iron flows into the pond, the two rows of people stir the molten iron with iron rods together......

As expected, Zhang Han fried pig iron into wrought iron in one fell swoop - wrought iron in the modern sense (^x^).

The quality of wrought iron is good, and Zhang Han made a batch of files with wrought iron carburizing, which was well received. However, Zhang Han wants to fry steel.

"Okay! Seventeen, it's not simple, well done! ”

Zhang Tingfang didn't care about Zhang Han's small failure, he sincerely praised Zhang Han. This time, Zhang Han really impressed him.

Frying steel and frying mature iron is a common mistake made by novices, that is, overfrying. At most, train these people to be veterans, that is. The completion of iron smelting and frying steel at one time is equivalent to two days of work in one day, which saves manpower and material resources. Zhang Tingfang knew from a simple calculation that the cost of smelting had been reduced by at least a quarter.

However, Zhang Han was not satisfied. Only easy operation can be convenient for popularization. Zhang Han requires quality, but also quantity. He found someone to try and test, and finally solved the problem. The method is very simple, replace the iron rod with a willow stick, and with the decarburization of the fried steel, the willow rod will continue to carbonize, and the carbon will be supplemented from it, so that the operation will not worry about frying mature iron.

Zhang Han knew that lime was needed in steelmaking. Although it is not clear what is going on, it does not prevent Zhang Han from making a bold attempt. In the process of frying steel, he added a small number of people and sprinkled lime powder on the molten iron. The lime floats on the molten iron and is not easy to disperse, so those who need to stir it should pay attention to stirring the lime more.

In any case, Zhang Han finally perfected the integration process of iron smelting and frying, and the quality of steel far exceeded that of any smelting workshop in the same period.

Of course, this is fried steel after all, and the quality is far from being comparable to 100 steel. In other words, Zhang Han is still unable to mass-produce high-quality steel.

At this time, Zhang Han remembered the famous steel filling technology.

Using the Lee's furnace, the coke is placed in the lower chamber, the wrought iron is forged into thin sheets, and the layers are stacked on the upper chamber, and the pig iron sheets are placed at the mouth of the furnace. The melting point of pig iron is low, the first to melt, use iron tongs to pick up the pig iron sheet, the pig iron liquid evenly poured on the wrought iron sheet, during which the wrought iron sheet should be turned from time to time, so that the pig iron water is poured as evenly as possible, and finally the steel can be filled.

Steel filling is actually a process of removing impurities, and most of the impurities have been removed from the steel obtained through this process, and the composition is close to 100 steel. However, the quality of steel-filled products depends on the craftsmanship of craftsmen, and the internal components are unevenly distributed, and there is still a big gap in performance compared with 100 steels.

With Zhang Han's level of knowledge, this is the highest achievement. If you want to go further, you have to wait for Li Shengzhong's crucible to come out.

As soon as the steel was filled with the wind, Li Shengzhong's intestines were repentant. After Wang Guanquan ran forward and backwards, under the guidance of Zhang Han, he quickly improved the steelmaking technology. has made a meritorious contribution and shown his face, and he is still tinkering with this broken cauldron.

If it weren't for Zhang Han's renewed emphasis on crucibles (Zhang Han: Nonsense!) I've always taken it seriously). Every time I come, I go to see his progress. And has always insisted on teaching Li Xiaoer - Li Shengzhong's son - literacy, Li Shengzhong ...... He still has to work on the crucible, and he has no way out.

[Be kind, read a book and smash the ticket]

PS: There is still at night.