Inside Laboratory 101.

"Gun barrel?" Wang Yingxuan pushed his glasses in surprise.

"Gun barrel?!" Zhao Shizhen also screamed, but he was more surprised.

If you ask him what else he is interested in besides guns, it must be cannons.

"The cylinder and the gun barrel have similar structures and similar requirements." Zhang Jian was not surprised at all. He had obviously long been accustomed to Zhao Hao's rhythm. "If they can cast qualified cylinders, gun barrels will certainly be no problem."

"Well, that's against the law..." his brother-in-law said timidly.

It's fine to make a gun in the name of the county. But if they make a cannon, my God, I can't believe it...

"I forgot to introduce to you that the full name of Institute 00 is the Ordnance Research Institute of the Ordnance Bureau of the Ministry of Industry of Nanjing." Zhao Hao smiled and gave a reassurance to the honest old Qin.

"Oh, so that's it..." Wang Yingxuan suddenly realized and thought to himself, no wonder Institute 00 is not with us.

"I saw it at the Arms Bureau last time, and the court also mostly had copper cannons," Zhao Shizhen recalled. "The Red Barbarian Cannon was supposed to be made of cast iron, but the barrel was as thick as a roof beam, and the barrel was only slightly bigger than a fist."

He was the director of the Ordnance Research Institute and was good at it, so he spoke with great familiarity: "The best artillery factory in the Ming Dynasty is the Bogalau Cannon Foundry opened by the Portuguese in Macau. I heard that they supply copper cannons to their own people."

"Yes." Zhao Hao nodded. He also thought about poaching the Portuguese craftsmen from Bu Jialao, but since they are not of the same race, their hearts must be different. Due to narrow nationalism, Master Zhao did not poach them.

After the failure of pig iron casting, he had three options before him. The first was to innovate the casting technology.

The reason why cast iron gun barrels are still difficult to use even though great attention has been paid to every detail is ultimately due to defects caused by natural cooling.

Because when the gun barrel is left to cool naturally, the outer wall of the gun barrel cools first, and then cools from the outside to the inside. This causes a serious problem - after the outer layer cools and hardens, the inner layer has not yet cooled, and the outer layer is harder than the inner layer. The inner tube of the inner layer will be pulled and deformed, and even cracks will appear directly.

This naturally leads to a high scrap rate when casting cannons, and will also cause the barrel to explode, making gunners afraid to try.

Therefore, at this time, both the Ming Dynasty and the Westerners could only thicken the iron cannon barrels again and again, but the cannons cast in this way were heavy and had little power, which naturally made it difficult to please the military.

It was not until the American Civil War that an engineer named Rodman invented the "internal mold water injection cooling method," which solved this problem by cooling the gun barrel from the inside out and then from the outside.

This method is simple to say. You only need to replace the inner mold of the barrel with a hollow one during the cooling process, and then cool it with circulating water.

But this is just a theory that Zhao Hao read from a book, and it is still far from being implemented - for example, what is the relationship between water flow speed and temperature change?

In the mid-nineteenth century, when thermodynamics had been fully developed and relatively advanced measurement and control conditions were available, Rodman still spent a full ten years to establish a relatively scientific and complete data system. How could Mr. Zhao achieve this quantification in the Ming Dynasty?

There is no other way but to keep trying and making mistakes to see if the blind cat will catch a dead mouse one day.

Zhao Hao's hope is to master this casting method within five years. After all, he has an advantage that Rodman doesn't have. As long as he does more experiments, he can make it with money.

But innovating casting technology is only a temporary solution. The real solution is to innovate smelting technology!

In another time and space, when the reverberatory furnace for pig iron refining appeared in the late 18th century, the British could perform a second smelting of the pig iron to remove impurities and make the molten iron purer. The cannons cast by the British Navy with this wrought iron never exploded. Finally, the copper cannons were completely eliminated.

However, the metallurgical technology and steel production of the Western countries are still far behind that of the Ming Dynasty. They naturally don't understand the technology that the Ming Dynasty doesn't have.

Mr. Zhao only had a general idea of ​​this, and was completely clueless as to how to do it specifically.

In fact, the Wuhu blacksmiths who produced "Su Steel" in the Ming Dynasty had already mastered the steel pouring method to control the carbon content in wrought iron. They also produced steel with various carbon contents according to demand. It was not until two hundred years later that the Europeans invented the crucible steelmaking method and barely caught up.

But whether it is the pouring steel method or the crucible method, there is a serious problem, that is, the production volume is too small and the cost is too high.

That’s why there is a saying that “good steel should be used on the blade”.

In short, people of that era could not imagine who would use extremely precious steel to cast cannons?

However, in the next few hundred years, all the powerful countries in the world will be made of steel. Therefore, no matter what the cost, Zhao Hao must manage the mass production of this damn steel.

When the first two methods are of little use, only the third method - 'casting cannons with copper' - is the only solution that can work immediately.

In fact, in the long years after the birth of cannons, copper cannons played the leading role for most of the time. All countries have a long history of copper cannon casting, and the Ming Dynasty naturally also has mature casting technology.

Copper is corrosion-resistant and not easy to rust, has good ductility and is not easy to explode, has a low melting point and is easy to cast. Therefore, copper cannons were more powerful than iron cannons for a long time.

The only problem is that it is expensive. Especially in the Ming Dynasty, copper is money!

Taking the current Portuguese bronze cannon as an example, the ship-borne heavy artillery weighs about one ton, and the light snake cannon weighs four hundred kilograms.

A Longqing Tong Bao coin of the Ming Dynasty weighs one qian and three fen and contains 95% copper.

The materials for a heavy cannon alone cost 216,000 coins, and taking into account labor and loss, the cost would be no less than 250 taels of silver.

The cost of a snake cannon is over fifty taels.

The Spanish or Portuguese capital ships were equipped with twenty to forty heavy guns alone, and countless light guns.

Not counting the cost of building the ship, just installing the cannons would cost around 10,000 taels...

~~

Master Zhao calculated silently and suddenly felt that he was probably not that rich anymore.

The mighty Spanish Empire could be impoverished by the arms race, let alone a small family like his?

Thinking of this, Master Zhao stared at Brother Four Eyes with a ferocious look on his face and said, "Even if we cast the copper cannon first, you must not slack off here. Within five years, you must overcome all the difficulties in converter steelmaking... and give birth to five sons!"

"Uh..." Wang Yingxuan took off his glasses and wiped them with a grunt. Similar to the 'water-cooled cannon casting method', the principle of converter steelmaking is also very simple. But this is more of a systematic project. Without long-term experiments and improvements, there is no way to talk about application.

Fortunately, five years should be enough.

But how is it possible to have five sons in five years?

Unless...but his brother-in-law is his immediate superior, and he dare not even have any improper thoughts.

ps. The first of three consecutive updates.