I'm the Dauphin in France

Chapter 1166 Artillery Expert (Seeking monthly votes at the beginning of the month)

As for the design of the projectile's shape and the mold, Kano will have to recommend some talented people to take charge of that.

Joseph did not intend to let his father get involved in any other weapon design matters before the steam forging machine was completed.

The next morning, when Joseph arrived at the Royal Ordnance Factory conference room, the breech-loading gun project team members were not yet all present—the design work for the breech-loading gun would be completed here later.

When Joseph saw that Cano had arrived and was sitting in a chair by the window looking at blueprints, he prepared to discuss the Minié bomb with him. However, the director of the engineering design institute looked up and saw him first, and then came up to him excitedly.

"Your Highness," Kano quickly bowed, then unfolded the blueprints in his hand, "This is a type of iron cannon barrel that I designed overnight."

Joseph then noticed that the dean's eyes were bloodshot, indicating that he hadn't slept much the night before.

He asked with some curiosity, "How did you come up with the idea of ​​using iron to cast cannons?"

Currently, bronze is the mainstream material for manufacturing artillery.

Because bronze has very good toughness, it is not easy to burst, and at the same time, it has a low melting point and is easy to cast.

Furthermore, the most advanced artillery production method today involves first casting a rough blank, and then using a boring machine to drill out the barrel. Artillery produced in this way is more robust than that produced by direct casting, and the inner wall of the barrel is also smoother.

Bronze is a relatively soft material, making it easier to drill.

Of course, some countries used iron cannons to reduce costs. However, due to the poor ductility of iron, the barrel walls had to be thickened to prevent them from bursting, resulting in iron cannons weighing more than 20% more than bronze cannons.

For artillery, every slight reduction in the weight of a cannon meant a greater degree of mobility. This is why firearms never became the mainstream weapon.

Carno quickly pointed to the blueprint, which depicted a cannon barrel:
"Your Highness, I considered it carefully yesterday. It would be best to use iron for the breech bolts and bolt slots, as you mentioned. Copper is too soft, and the threads are easily deformed under the impact of firing."

"In that case, if a bronze cannon barrel is used, there will be a problem of how to rivet the airtight parts of the cannon barrel and the breech."

"I believe that even with the best riveting technique, the joints will loosen after repeated firing."

"Therefore, the best solution is to use an iron barrel and cast it as a single piece with the breech. This is the only way to ensure the overall reliability of the cannon."

Joseph looked at the dean with some surprise. He had indeed overlooked these issues, while the dean not only thought of them immediately but also drew up a sketch in one night.

Joseph first nodded, acknowledging that Cano's plan was indeed more robust, then hesitated and said:

"But regarding the weight of the artillery..."

Cano immediately broke into a bright smile, looking quite pleased with himself:

“Your Highness, I have reviewed the technical documents of the Namur Royal Ironworks. The alloy steel they produce is 2.5 times harder than ordinary steel and more than 4 times more wear-resistant.”

Due to the secrecy surrounding manganese steel, even he only knew that it was an alloy steel, but not the components that were incorporated into it.

"If we use this alloy steel to make the inner wall of the cannon barrel and wrap the outer layer with wrought iron, then the weight should not exceed that of a bronze cannon. You see, this is my calculation process..."

Joseph looked at the densely packed formulas and felt a bit overwhelmed, but he was confident that the director of the engineering design institute couldn't be wrong—this man had written "Introduction to Mechanics" and "Position Geometry," and his basic skills were definitely solid.

Moreover, he also knew that, judging from the development of artillery technology in later generations, iron cannons would be even lighter than bronze cannons.

In the past, to ensure the wear resistance of the cannon barrel, high-carbon steel could only be used for casting. Although this material is hard, it is also relatively brittle, so the only way to prevent the barrel from bursting was to increase its thickness.

Now, with the ultra-hard material manganese steel, a very thin layer is sufficient to ensure no wear even after thousands of shots. The outer layer is wrapped with wrought iron or low-carbon steel, which is highly tough but not wear-resistant, to withstand the chamber pressure. Since iron has a much lower density than copper, it is entirely possible to keep the weight under that of a bronze cannon.

Joseph nodded approvingly:

"I think your idea is very feasible."

In France today, thanks to patent laws and talent incentive policies, technical personnel are highly motivated. Coupled with breakthroughs in precision machining technology, a surge of new inventions is inevitable.

Cano's cannons are one example.

Cano rubbed his hands excitedly and said:

"I just don't know if there will be any difficulties in the casting process."

As he was speaking, he saw a slightly overweight man, who was at least 1.9 meters tall, walk in, and quickly waved to him.

“Mr. Verdrina! Excellent, your knowledge is exactly what we need here.”

This burly gentleman is one of the casting experts in the project team.

A few minutes later, Verdrina looked at the blueprints and frowned slightly:
"To be honest, there is no problem with light artillery, but if it is a heavy artillery weighing more than 24 pounds, then the thickness of the barrel wall in the design should be increased by at least 15%, or even 20%."

Cano felt his technical abilities were being challenged and protested:

"That's impossible! I've calculated it repeatedly. Even if the propellant charge is increased by 15%, this thickness is enough to withstand the chamber pressure!"

“You’ve overlooked the damage caused by the expansion forces during the cooling process of the steel,” Vedrina patiently explained. “If the barrel wall is very thick, the temperature difference between the inner and outer layers will be significant.”

"When the outer side cools and contracts, the inside is still red-hot."

"Once the inner wall begins to cool, the outer layer has basically solidified. At this point, the inner wall shrinks and peels off from the outer layer."

“You’re using the strength of fully cooled steel for your calculations, but in reality, cast iron cannons are far less robust.”

Carnot was stunned—uneven cooling could indeed reduce the strength of the gun barrel structure.

Verdrina then suggested:

"Or you could use bronze for the outer layer. As you know, bronze has a very low melting point, so the inner alloy steel won't soften from the heat after casting."

Cano shook his head in frustration:
"No, if we use a bronze outer shell, there will be a problem with riveting it to the breech."

Joseph suddenly thought of something and looked at Vedrina, saying:
"So, as long as the inner alloy steel can maintain sufficient hardness, there's no need to increase the thickness of the gun barrel?"

“Theoretically, that’s correct, Your Highness.” The latter nodded. “It would probably only require an increase of about 3% based on Mr. Cano’s calculations.”

Joseph immediately said, "Then I have an idea. If we drill a hole in the middle of the cannon mold and let cold water flow through it, the inner layer of the cannon barrel can always be kept at a low temperature during the casting process."

Yes, this is the Rodman casting method that emerged during the American Civil War—using a very simple technique to help increase the lifespan of iron cannons by as much as five times.

(End of this chapter)