The key to manufacturing steel crossbows is batch heat treatment and batch carburizing. The key lies in the earthen kiln.

To find out, Li Mengxi planned to build a hundred earthen kilns. This was a grand test.

Li Mengxi's plan was to find a flat and wide area and build a hundred standard rectangular coffin-shaped earthen kilns.

The reason why it is specifically built as a rectangular parallelepiped is because the volume of the rectangular parallelepiped is easy to calculate and control.

And if it is built in a dome shape, the size and volume of the kiln will be difficult to control.

In terms of the design of the kiln, the earthen kiln has a simple structure and can be built with only loess. It is best to build it into a dome shape because the dome shape naturally has high strength. However, if combined with the experimental requirements, the dome structure cannot be built.

Standard spherical shape, so the internal volume is not easy to control.

The control of the internal volume of the earth kiln is the key to accurately controlling the oxygen in the earth kiln, thereby further controlling the flame burning time and further controlling the temperature in the kiln.

Therefore, in order to conduct accurate experiments, we can only use regular rectangular kiln bodies.

After convening a large number of craftsmen and workers, Li Mengxi handed over the construction task to the builder who had built the altar before. The construction requirements given by Li Mengxi were that all earthen kilns and kiln rooms must be six feet high, with the front and back equal.

High, not too high.

Second, the kiln wall should be as thick as possible.

Third, the cave dwelling must be easily sealed, and the tighter the seal, the better.

Fourth, a charcoal pool must be built in the kiln, and the charcoal pools must be the same size.

The required one hundred earthen kilns must be exactly the same in height and width, but their depths will increase in sequence.

The first kiln was six feet high, one foot wide and five feet deep.

The second kiln is six feet high, one foot wide and six feet deep.

Going back in order, seven feet deep, eight feet deep, nine feet deep, ten feet deep...

Finally reached a hundred feet.

The key to the entire construction is obviously precision, which requires adding the kiln deeper one foot at a time.

This requirement is to allow the oxygen volume in the kiln to increase foot by foot to achieve the effect of gradient temperature.

After the city builders took over the task, they were faced with many demands. The experienced city builders could see at a glance that the key was to increase the kiln length by one foot.

There was just one problem: the kiln was only six feet high, and it was very inconvenient to get in and out with your head down. The craftsman suggested that the kiln be built higher. Li Mengxi smiled slightly and said, "No, the kiln is lower, which is exactly what you want."

So why should the earthen kiln be built so low? The key point is that it is easy to control the volume.

From the perspective of the kiln itself, the method of controlling the volume is either to control the height and width, or to control the length and fix the height. This is the most convenient method by extending the length.

To control the height, the wall must be raised little by little. Finally, when it reaches a height of 100 feet, will it not collapse?

The reason why the width is not controlled is that the kiln is only made of loess. If the horizontal span is too long, the kiln will collapse.

Therefore, the only option is to increase the length of the kiln.

In order to subdivide the temperature gradient as much as possible, the lower and narrower the kiln is, the more slender the kiln is. Each additional foot of length will increase the volume less, thus making the gradient more subtle and making the test more accurate.

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In order to make the kiln erection as accurate as possible, the builder took people to measure it in person with a ruler and rope.

Li Mengxi knew that it would take several days to complete the construction and use of these one hundred kilns.

This is still the preparation of the test site. During the test process, a large number of iron sheets will be needed.

There are hundreds of kilns. If you put ten iron bars in one kiln, you will get a thousand iron bars.

Moreover, these thousand iron bars must be of the same thickness, length, and width. Not only that, they must also have the same quenching strength. Otherwise, there is no way to test them.

According to Li Mengxi's understanding, according to the method of making iron tools with bare hands, when craftsmen make swords, the weight of the finished swords is very unstable, heavier and lighter, and there is no way to produce a thousand steel swords with exactly the same length, width and weight.

strip.

Considering this, it cannot be made by forging, but casting.

Using the same mold and casting it with molten iron, it is possible to produce a thousand iron bars with extremely small errors.

As for the method of casting iron, Li Mengxi was not sure about the durability of the mold after thousands of castings, whether the mold would be damaged halfway through casting, whether it would expand and increase the weight, etc.

When Li Mengxi went to the blacksmith camp with questions, he told the problem to a group of craftsmen. The craftsmen hesitated and said, "I am afraid that the mold cannot withstand a thousand castings. If it is cast thirty or fifty times, I am afraid it will be inaccurate."

Li Mengxi suddenly frowned, "Then... what should we do?"

The experienced craftsmen easily gave Li Mengxi a solution.

The craftsmen said, "It can be cast separately from the master mold."

The so-called master mold split casting method is to first create a master mold, then cast some iron bars, and then use these cast iron bars as a basis to make molds.

Li Mengxi understood the master mold method, but according to what the craftsmen said, the simple molds made by the army now using yellow mud, plant ash, linen and other rags are no longer accurate after being cast thirty or fifty times.

To be safer, cast it twenty times.

Cast twenty iron bars in the first mother mold, then cast twenty iron bars in the second batch, to get four hundred, and then cast four hundred, and cast each mold three times to reach the required number of one thousand.

There is just one thing. Li Mengxi feels that the more times the mold is replaced, the greater the error will be.

He asked the craftsman if the iron bar would become heavier if the mold was turned over three times.

The craftsmen thought carefully and said, "Maybe it will be a little heavier."

Li Mengxi frowned again, "What should we do?"

The blacksmiths said, "It's no big deal. It's not too heavy. Just rub it with a file a few times and it'll be done."

Perfect.

Although the mold is indeed heavier as it is cast, it is not much heavier. It weighs only one or two grams at most, and three to five grams is as high as the sky.

I just rubbed the next batch of finished products with a file and the slight error was smoothed out.

But in fact, it doesn't need to be so precise. A few grams lighter or a few grams heavier doesn't affect the experiment at all.

Li Mengxi received important help from the craftsmen. According to the custom of the craftsman camp, Li Mengxi wrote down military coupons totaling one hundred kilograms of grain and distributed them to several craftsmen.

This chapter is not finished yet, please click on the next page to continue reading the exciting content! The craftsmen were overjoyed to receive military tickets.

When several craftsmen who were extremely happy continued to return to the construction site and were busy, when the craftsmen nearby asked, they all felt envious. At the same time, they also thought that the next time they saw the military adviser, they would also join in the front. Once again, the craftsmen

The atmosphere at the camp that inspires talent and creativity has once again been enhanced.

——

Li Mengxi already knew how to make a thousand iron bars of the same specifications, but it was not possible to use pig iron or wrought iron bars. No matter how they were quenched, these two iron bars would be either too hard and break when pulled, or too soft when pulled.

As far as deformation is concerned, it cannot be tested as a crossbow arm of a steel crossbow.

So, you still need steel.

When it comes to steel, there is no more steel.

Because spring is just around the corner, a large amount of iron materials have to be saved to prepare the curved shaft plow. The curved shaft plow is the key, and the business cannot be delayed for a little experiment.

However, the steel crossbow and the batch heat treatment process were also important. Li Mengxi couldn't wait a few months before testing again, so he had to find more iron materials.

After thinking about it, Li Mengxi went to the war camp to find Guan Yu.

Since the war camp was divided into camps, the atmosphere in the camp has become very solemn. Today, there was a big drill in the camp, and the whole camp was filled with the sounds of shouting and commanding in formation.

Li Mengxi found Guan Yu and explained his intention to come.

"General Guan, give me two thousand ring-headed swords." Li Mengxi reached out and asked for two thousand.

Guan Yu was stunned for a moment, and then said, "Huh?"

Guan Yu looked at Li Mengxi in surprise, "Is it a lack of iron? Is it a thousand percent?"

Li Mengxi shook his head, "Not enough." He gestured with his hand, "The steel crossbow bars are long and wide, longer and thicker than the Huanshou knife. A thousand knives are not enough to make a thousand steel bars."

In order to make the Quyuan plow, the army had mobilized 1,500 weapons and melted them. Where can we find such defective weapons now?

Hesitating and hesitating, Guan Yu rubbed his hands, with a look of embarrassment on his face, and he discussed, "Xi'er, there are more than ten thousand soldiers in the army now, and the generals are barely equipped with only one weapon. You can take away two thousand swords at once."

, then someone has to use bare hands. Besides, after the last time, there are not so many broken swords, and the rest are all good..."

Li Mengxi was very aware of Guan Yu's difficulties, but he still refused to give up. After thinking for a while, Li Mengxi looked at Guan Yu with a smile and said bewitchingly, "General Guan, you might as well think about it this way.

Swords are no match for spears in battle formations, right?

A small knife weighs more than one kilogram, a heavy one weighs two or three kilograms, and the head of a spear does not weigh more than two or three kilograms.

If two thousand knives were melted, it would be enough to make five thousand gun heads. Wouldn't that double the military equipment?

Furthermore, the art of pouring steel has been completed. All it takes is to remelt the sword and make it into a weapon. It can be several times stronger and sharper. With this method of reducing the bad and making it better, how can you say that the old thing is good?"

Guan Yu thought for a while, then gritted his teeth and said, "Okay! I'll get it for you!" Guan Yu clapped his legs and stood up.

Two thousand knives are a lot. Guan Yu summoned all the soldiers, and then led the centurions to check the knives one by one. There is no need to melt the good knives such as those made of hundreds of refined steel. Such good knives are better than the steel knives.

The better ones will suffer a bit of a loss after being refinanced, but other than that, the slightly inferior ones will all be taken away.

The current situation in the army is that the really damaged and inferior swords have been collected last time, and the remaining ones are all good ones. Although Li Mengxi has a method of pouring steel, it is true that one sword can be melted to make five guns.

But when Guan Yu saw the good knives with bright blades being thrown at the car like rags, Guan Yu's heart was bleeding.

Simply, Guan Yu turned his head and stopped looking.

After a long time, more than two thousand knives were collected. Many soldiers in the army had no hair on their hands. Guan Yu had to comfort these soldiers who had lost their weapons.

Afterwards, after handing several carts full of jingling bells and swords to Li Mengxi, Guan Yu smiled bitterly and said, "That's all. If there is any shortage of iron, there will be nothing left."

Li Mengxi looked past Guan Yu and looked back. He saw that many of the soldiers still had spears in their hands, and the soldiers had stomachs on their bodies.

It was enough to say this verbally, but Li Mengxi thought to himself, if there is a shortage of iron again, will the armor be melted or melted?

Anyway, how can ordinary iron armor have better defensive effect than armor made of filled steel? It can be regarded as an upgrade of military equipment.

After Li Mengxi's second search, the number of knives in the army dropped sharply. This had a serious impact, that is, all the knives that still existed in the army were of high quality.

Li Mengxi brought several large carts, swords and swords to the blacksmith camp, and asked the craftsmen to follow the old method to separate pig iron, wrought iron and fine steel weapons, and then redo a large iron pool to prepare for steel production in the future.
Chapter completed!