When iron-making started, it was no longer appropriate to say iron-making, but steel-making was more appropriate.

In the blast furnace, a furnace of iron has not been burned out yet, so it is not possible to add more iron to the furnace for the time being.

Li Mengxi said to the craftsmen, "There are still few iron-making furnaces. We can build a few more big ones and another small one. The smaller the better."

Li Mengxi had his own considerations for building an ultra-small iron-making furnace. The top priority now is to mass-produce plows in preparation for spring plowing, so mass production is required. At the same time, production belongs to production, and technology research and development belongs to technology research and development.

Don't delay either.

Small iron-making furnaces, because the furnaces are small, can make iron in small batches very quickly, which is convenient for technology research and development. However, for large iron-making furnaces, it only takes half a day to preheat.

Previously, the blacksmiths were asked to produce small iron boxes for charcoal, which were used to burn different types of charcoal in batches. The principle is the same.

The iron-making furnace was not vacated for a while. Li Mengxi recalled the process of the steel pouring method. It seemed that the more specific process of the steel pouring method was to build an iron frame on the ground, then pour the molten iron into the iron frame, and then place several raw/wrought iron pieces.

Put the pieces into the oven, wait for the iron pieces to melt, and stir with a stick.

Li Mengxi suddenly remembered that the steel-filling method involves mixing pig iron and wrought iron. So, should pig iron be added to the wrought iron juice, or should pig iron be added to the juice and wrought iron pieces be added?

Which one is it? Li Mengxi was confused. There was a loophole in his limited knowledge here.

I walked to the iron-making furnace and saw that there was an iron pool in front of the iron-making furnace and the iron mold was already there. However, when the molten iron flows out of the furnace, is it pig iron juice or wrought iron juice?

Unable to figure it out, Li Mengxi could only ask the craftsmen for help.

The craftsman said that when iron comes out of the furnace, it must be pig iron juice.

This "must" puzzled Li Mengxi a bit.

When the iron material comes out of the furnace, if it must be pig iron, then if a pile of wrought iron knives are put in the furnace and burned into molten iron, then the molten iron turned into molten iron by the wrought iron knives is wrought iron or pig iron?

When I think about it, it's still pig iron.

Because even if it is a wrought iron knife, as long as it is heated in the furnace, the charcoal inside is burning, and the wrought iron will become pig iron after passing through the furnace.

At this point, the technical details are clear. Since the product coming out of the furnace must be pig iron juice, if the steel filling method is used, just throw the wrought iron pieces directly into it.

——

After an hour and a half, a furnace of mixed iron came out of the furnace, and the molten iron slowly flowed along the groove into the iron pool.

Li Mengxi immediately threw the prepared wrought iron knives in and waited for them to melt.

I thought it was foolproof, as long as the blade melted and the steel was filled, it would be done.

However, after waiting for a long time, I watched the molten iron in the pool cool down from bright to red, and then gradually darkened. After a long time, the iron liquid had cooled and solidified, and the few wrought iron knife strips that were thrown in were only burnt.

Red, no melting seen.

Li Mengxi was at a loss.

He scratched his head and thought hard, but couldn't figure it out.

Doesn't it mean that the iron juice flows into the fan and then throws a few raw/cooked iron bars into the plow? But why, the iron bars failed to melt.

Could it be that the iron bar didn't penetrate deeply into the molten iron? But that's not right. They inserted the knife bar deeply into the pool, but the part under the pool still didn't melt.

Li Mengxi couldn't figure it out for a long time. He looked up at the blacksmiths gathered in a circle and asked helplessly, "Do you know why the cooked knife strip failed to melt when it was inserted into the pig iron juice? Why?

"

The blacksmiths all laughed.

"It's definitely not possible. Can it be transformed?"

"It can't be melted."

"Pig iron is not resistant to burning, but wrought iron is resistant to burning."

"In turn, it will be the other way around."

…

The blacksmiths actually knew why the wrought iron bars had not melted, and they started discussing it in various ways.

Li Mengxi heard this and was confused, "Well, why is it that wrought iron is difficult to dissolve in a pool of pig iron, but vice versa? What does this mean?"

Later, under the patient explanations of the blacksmiths, Li Mengxi vaguely understood.

According to blacksmiths, pig iron is easy to melt and will become soft after being heated for a while, but wrought iron is not good and will not melt after being heated for a long time.

It turns out that the melting of pig iron is different from that of wrought iron. The melting of wrought iron is much higher than that of pig iron. Therefore, the temperature that can turn pig iron into juice is not enough to melt the wrought iron, so the cooked knife strips are thrown into the pig iron pool.

Will not melt at all.

So, it's just the other way around.

Instead, let the wrought iron flow into the mold and throw the pig iron bars. In this way, the pig iron bars will definitely melt.

But, what is the reason? Why does the melting rate decrease if there is too much carbon in the iron, and the more carbon there is, the lower the melting rate decreases.

Li Mengxi frowned and thought for a long time. He thought of another thing. It was taught in physics or chemistry classes in junior high school or high school. It was probably said that the more impurities in a substance, the easier it is to melt.

Therefore, if you want the snow to melt faster on a snowy day, sprinkle some salt, or sprinkle some snow, or anything that is not snow, to make the snow melt faster.

It turns out that charcoal is also an impurity in iron. When impurities are added, the iron melts and the content decreases.

Therefore, pig iron with impurities is easy to melt, while pure iron without impurities is not easy to melt.

I see.

The relationship between melting point, impurities, impurities and the melting point of substances. If you want to make a substance that is not easily meltable easier to melt, just add impurities. Li Mengxi suddenly realized.

I figured it out, it turns out that the steel filling method is not about randomly hitting the pig iron and the wrought iron, but the pig iron pieces must be thrown into the wrought iron pool. If it is reversed, the iron pieces will not melt.

But then I thought again, and still couldn't do it. I rejected the blacksmiths' suggestion that the iron juice coming out of the furnace is all pig iron juice. Where can I find the wrought iron juice? Wrought iron is not easy to melt and the temperature is difficult to reach. Do I have to find coal?

Another problem faced Li Mengxi.

Li Mengxi asked the craftsmen with confusion, "I know pig iron, but how did pig iron become wrought iron?"

The craftsman replied that pig iron can be obtained by melting it and frying it, or that it can be hammered and hammered repeatedly to obtain wrought iron.

Alternatively, the pig iron can be heated and thinned, and then placed in a flat place to allow it to cool by itself. When cool, it will transform into wrought iron.

Stir-frying and stir-frying are also methods of steel. When he heard that wrought iron is made by stir-frying, Li Mengxi was immediately filled with worry. The production of wrought iron turns out to be the same process as stir-frying and forging steel. This is good. Stir-frying is the same process.

Whether steel or forged steel, it is time-consuming and labor-intensive, and the output is low. There is no way to mass-produce wrought iron. Without a large amount of wrought iron, how can the steel filling method be used?

Another thing Li Mengxi didn't understand was that since the production of wrought iron and steel is the same technology, and the principle is the same, both of which reduce the carbon in pig iron through frying or forging, then why not just forge steel from pig iron instead of

If we want to go further to produce wrought iron, what's going on with so many wrought iron knives in the army?

The craftsmen's answers dispelled Li Mengxi's confusion. It turns out that whether it is steel-making or frying, the amount of decarburization of pig iron is difficult to control. If there is less forging, the carbon content is high, and the knife will still be brittle when struck.

If you beat it too much, the charcoal will become clean and become wrought iron, which will become soft.

But it is difficult to say that the control is just right.

In one word, yield is a problem.

Whether it is fried steel or forged steel, the final products include pig iron, wrought iron, and steel. The three products obtained are unstable.

The carbon content during the forging process is really difficult to control, so it is better to simply hit it hard and drain out the carbon in one go, and then consider carburizing. In this way, from pig iron - wrought iron - carburizing to steel,

This step is much simpler than going from pig iron to steel.

Li Mengxi understood why there were so many wrought iron knives.

Wrought iron turned out to be much rarer than pig iron, which made Li Mengxi realize that the steel filling method was not as cheap as he thought.

I repeatedly checked with the blacksmiths to see if it was possible to directly turn wrought iron into molten iron. The blacksmiths said that I couldn't, as wrought iron can only be softened by burning, and it is difficult to turn it into water.
Chapter completed!