At present, even the mass production of steel has not been realized, and the mass production of special steel is impossible to talk about, so we can only find a way to break through from the technical level.

Zhu Shun walked back to the cannon casting workshop with Zhao Doumi and asked, "Have you tried the Western cannon casting method?" ”

Zhao Doumi nodded first, and then shook his head: "Master, the Western yang mold casting method has been tried, but it can't make the cannon breech the hardest." ”

"After the cannon is cast, the speed of cooling affects the mechanical properties of the gun, and the faster it cools, the harder the texture."

"If you want to increase the service life of the gun, you can only improve the service life by making the gun chamber the hardest to do so, that is, let the gun chamber cool down first."

"But the reality is quite the opposite, castings are generally cooled from the outside to the inside, the gun body is cooled first, and gradually cooled to the inside as the temperature decreases."

"That's why the cast cannon is buried in the soil for one to two days, and the chamber can't be cooled first, but the cooling rate of the chamber can be consistent with the barrel."

Zhu Shun is very clear about the physical phenomenon that his disciple Zhao Doumi said, the heat dissipation speed and the surface volume are equal, and the surface area of the cannon body is larger than the gun chamber, so the cooling speed is faster.

The cannon body shrinks first when it cools down, which also causes the cannon body to be cooled and hardened, and the gun chamber has not yet been cooled down, and the texture is softer than the gun body.

It often causes the deformation of the gun chamber, and cracks will appear on the inner wall of the gun chamber if it is serious, and the number of defective products will increase.

Therefore, after the casting of the Hongyi cannon is completed, it will generally be filled with water to test whether there are cracks in the breech that has been completely cooled.

In order to increase the service life of the gun, the technical difficulty lies in the cooling rate of the gun chamber.

Zhu Shun gradually had an idea, but he didn't know if it was feasible or not: "Doumi, call a craftsman to demonstrate the Western casting method." ”

Zhao Doumi saw the expression on his teacher's face, did his teacher have a solution? I quickly went to find a cannon casting craftsman who was proficient in Western cannon casting methods.

When the gunsmith came over, it was actually a red-haired gunsmith from the Netherlands wearing a green cloth placket.

Zhao Doumi saw the confusion in his teacher's heart, and explained: "This is what the second uncle bought from Westerners for money, and those Westerners really don't know the teachings of the saints, and they have no humanity at all. ”

"I rushed to send Western gunsmiths and scholars to Songjiang Mansion for some silver, and I heard from the steward who came to send the gunsmiths that the Westerners' eagerness to sell their own people was about to reach a crazy level."

The captains and so-called navigators of the Age of Discovery are indeed a bunch of scum, and there is nothing they dare not do for the sake of gold and silver.

The Jin merchants of the Ming Dynasty are no better, and those scum have a virtue, as long as there is silver to collaborate with the enemy and betray the country, it is called a hard work.

Zhu Shun thought of the group of Jin merchants who collaborated with the enemy and betrayed the country, and felt a little unhappy, and when the industrial revolution was completely spread in the five northern state capitals, there was time to slowly kill these traitors.

The master and apprentice talked a few words, and the Western gunsmith began to demonstrate the Western male mold casting method.

First of all, a male mold was made, and the Western gunsmith took a cone-shaped piece of wood as a support body, and wrapped it tightly with straw rope to form the shape of a cannon.

The wrapped male mold is much smaller than the gun chamber, and the surface of the male mold is at least 30 cm away from the gun chamber, and you can proceed to the next step.

After wrapping, the two apprentices also stirred out a large amount of mud with clay and water, and the Western gunsmith evenly applied the clay mud layer by layer to the surface of the male mold, and each time it had to wait until it was completely dry before continuing to paste the next layer.

Because it was just a demonstration, there was not so much time to wait here for layers of mud and water to be painted, so the Western gunsmith demonstrated three or four layers and asked a few apprentices to bring a painted male model.

The Western gunsmith took out a shovel and a carving knife and other tools to correct the surface of the dry male mold, just like the Ming Dynasty casting method carved paraffin, and corrected the male mold to be consistent with the gun chamber.

Zhu Shun watched from the side for a while, and just when the Western casting cannon was about to start demonstrating the next step, he said an inexplicable sentence: "The male mold should be brushed a few more layers, at least 1 cm thicker than the normal male mold." ”

1 cm thick?

Zhao Doumi looked at his master puzzled, could it be to cast a larger caliber artillery, but it was not right, how could there be a cannon with a larger caliber of 1 cm, and only defective products that did not meet the standardization would only be 1 cm larger.

Zhu Shun didn't explain, he only said that the thickening was at least 1 centimeter and didn't say anything, at this time, the students of Jingshi University heard that the mountain chief had found a way to cool the cannon chamber first, and they successively put down the research in their hands and walked over.

Just as the Western gunsmiths had finished making the new male model, the students of the Beijing Normal University Hall who were in charge of the munitions research had basically arrived, and they stood by to observe after saluting Zhu Shun.

After the production of the new male mold was completed, the next step of production began as usual, and a layer of paraffin wax was applied to the surface of the male mold, and the positive male mold became very smooth.

After the production of the male mold, the next step is to make the casting mold of the cannon, that is, the outer mold that wraps the cannon.

In addition to clay, clay, fine sand, and water are also needed to mix semi-liquid mud and coat the male mold layer by layer.

The casting mold also needs a long time of natural drying, but fortunately, there is no rigid requirement for the casting skills of the casting gunsmith in the casting workshop, and it must be unified.

Not everything needs to be unified, and this is not reasonable, after all, the craftsmanship of gunsmiths has been skilled for decades to reach the point where it is today, as long as it can deliver guns of a uniform caliber on time.

The craftsman of the Western gunsmith had a casting mold that had been dried in the shade, and Zhu Shun and the others walked to the place where the casting mold was placed and continued to watch.

The Western gunsmith first observed the degree of dryness of one of the casting molds, and the degree of dryness and hardness was almost the same, and took out the male mold.

A layer of paraffin wax was applied in advance between the casting mold and the male model, and the male model was easily removed, and the two apprentices carried the male model and placed it aside.

Once the mould is cast, the next step is to make the core, a cylinder made of clay.

The manufacture of the core also takes time to wait for the clay to dry, and on the concrete ground not far from the Western gunsmith, there are standardized cores made in advance, such as tiger squat guns, 500 catties of field guns, and thousand-pound siege guns.

The Western gunsmith walked over and took the core of a tiger squat gun, installed it in the main mold, and finally buried it in the concrete round pit next to the cast iron furnace like the Daming casting gunner, and filled it with soil.

After completing this step, the Western cannon casting method is over, and then you only need to pour the melted iron into it to get a rough embryo of a tiger squat cannon.

As long as the parameters are qualified, the equipment can be factory.