The next day, Liu Yan sent a fast horse to the Lingshan Acropolis, and asked the integrity officer Hu Zongming to transfer the gunsmith, Hu Zongming responded to Liu Yan's request at this time, directly sent a gunsmith named Cui Mingyuan, and sent a few family members to send Cui Mingyuan over, the next evening, Cui Mingyuan, who was almost frozen, rushed to the Wangjiazhuang Baihu, at this time Liu Yan had already taken Qian Qian to get here first.

In the main hall of the 100 households in Wangjiazhuang, a middle-aged man trembled and hugged his fists and said: "Big, big, villain Cui Mingyuan, I was ordered to come and ......."

Seeing this, Liu Yan smiled and said, "I know, sit down and drink some hot tea first, warm and warm, and you will have to learn the art of casting cannons with me overnight in a while." ”

Cui Mingyuan is a nearly forty-year-old man, short and sturdy with a long face, full of vicissitudes of life, who has worked in the Lingshan Acropolis for more than ten years.

But at this time, Cui Mingyuan heard that Liu Yan was going to teach him to cast cannons, and he was stunned, this defensive adult in his early twenties in front of him still knew how to cast cannons?

Qian Yan, who had just been appointed as the flag commander of the artillery team and followed Liu Yan to the Wangjiazhuang Hundred Households, was also surprised, but he didn't expect what Liu Yan said to be true, did he really know how to cast cannons?

Before Liu Yan rushed to Wangjiazhuang Baihu, Qian Jian and a group of subordinates were organized into a banner, a tiger cannon composed of a captain, an aiming and firing man, a loader, and a cannonballist, a total of four people, and five Huzun cannons were twenty people.

Qian Liang, the chief flag officer, also had a herald and a drum and bugle bearer, a flag bearer, and four guards, and there were 27 people in the artillery team.

Although the artillery team is not large, it is a new force of the Xiahezhai New Army, and Liu Yan believes that with his own knowledge and the blessing of Cui Mingyuan and other gunsmiths, the scale of the Xiahezhai New Army artillery team will become larger and larger.

At this time, Cui Mingyuan learned that Liu Yan knew how to cast cannons, and his heart was also strange, so he wanted to see what kind of cannon casting technology Liu Yan said.

So Cui Mingyuan hurriedly said: "My lord, the villain doesn't need to rest, it's much better now, why don't we go to the workshop now." ”

Seeing this, Liu Yan didn't shirk, after all, the time was tight now, so he smiled and said, "Okay, let's go to the Firearms Supervision Office now." ”

At this time, Chen Xun, the head of Baizong, had already led his troops to gather in front of the Qianqian Household in Xiahe Village, and he was not here. Liu Yan took everyone to the firearms supervision office, for the time being, there is no place for casting artillery, so Liu Yan called Tan Xiaoda to prepare to test casting artillery in the firearms workshop first.

Tan Xiaoda was also surprised when he heard the news, so he came over to find out.

So Tan Xiaoda instructed his craftsmen to hurry up and prepare, and prepared all the iron materials and tools, during which the gunsmith Cui Mingyuan also helped, instructing those apprentices and craftsmen to replenish some tools.

At the same time, Tan Xiaoda carefully selected twenty craftsmen from among his subordinates as the main people for casting artillery, and obeyed the command of Liu Yan and Cui Mingyuan.

Fortunately, there is a lot of high-quality pig iron in the Firearms Supervision Office, so it is good to take the main materials needed for casting cannons directly.

At this time, seeing that everything was ready, Cui Mingyuan also wanted to see what Liu Yan's technique was like, and what was the difference between it and the cannon casting technique he knew, so he said with a smile: "My lord, are we starting to cast cannons?" ”

Liu Yan saw that Cui Mingyuan was anxious, and said with a smile: "Then Master Cui will talk about the doorway of this cannon casting first." ”

Cui Mingyuan saw that Liu Yan wanted to test himself, so he smiled, he had already done enough homework before, so he said: "The villain obeys, it is best to use copper for this cast cannon, so that the life of the cannon will be much longer than that of the cannon made of pig iron." If you use pig iron cast guns, the cost will be much lower, and pig iron has less sulfur content, which is also very suitable for cast guns, so the villain suggests that we use pig iron cast guns. ”

Liu Yan listened to Cui Mingyuan's words, and recalled some information in his mind: in history, the pig iron produced in the Fujian and Guangdong regions of the Ming Dynasty was known for its superior quality, and the iron-making workshops in this area used charcoal as fuel to make iron, and the sulfur content was much lower than that of pig iron smelted from coal in the north. Sulfur is a major factor in making pig iron brittle and deteriorating in quality.

The people of the Ming Dynasty could not understand this reason, but it became a consensus at that time that the artillery cast in the south was stronger than that in the north, so that by the end of the Ming Dynasty, the large-scale cannon casting in the imperial court was carried out in Guangdong.

Later, in the 47th year of Wanli, when Xu Guangqi was ordered to train troops to defend the capital, he suggested that the imperial court recruit craftsmen from Fujian and Guangdong to cast cannons in Beijing. In the third year of Chongzhen, he invited himself to Guangzhou to cast cannons, and the reason is: "There are many craftsmen, the iron material is particularly fine, and the price can be saved by one-third ......" and in the early years of Chongzhen, Wang Zunde, the governor of Guangzhou, cast 200 cannons at one time.

Of course, these are the conditions of the late Ming Dynasty, but at this time during the Jingtai period, the casting skills and numbers of cannons in the south of the Ming Dynasty have begun to surpass the northern provinces.

However, at this time, the Daming artillery had some defects, that is, the charge was small, the firing range was short, and there was no crosshair, so it could not be accurately aimed, the outer mouth of the gun bore was wide, the inside was small, and the gunpowder gas could not be effectively gathered, and the inside of the gun bore could not be qualified to be circular, the gun bore was not bored, the size and even shape of the shell were arbitrary, and the playback of the projectile was too large.

In addition, the cannon has no lugs, and it is top-heavy, and if the charge is too dense, it will explode upside down and itself when the gun is fired.

Therefore, before coming to the Firearms Supervision Office, Liu Yan had already made up his mind to improve these shortcomings of the existing artillery of the Ming Dynasty.

After all, Liu Yan had seen a lot of relevant materials before the crossing, although he was not from a "professional class", but he could also use his theoretical knowledge to thicken the pipe wall of the artillery, increase the diameter of the artillery, and at the same time thicken the cannon body from front to back.

In this way, the guns forged by the Firearms Supervision Office will have many advantages in terms of range, lethality and safety.

At the same time, Liu Yan also prepared to add a crosshair and a light door to the new artillery cast by the Firearms Supervision Office to increase the accuracy of the artillery; The addition of lugs to the gun body makes it easy to mount the gun on the gun carriage, as well as to adjust the firing angle and facilitate movement.

Before coming to the Firearms Supervision Office, Liu Yan had already drawn a sketch of the new artillery, and the artillery to be manufactured this time was a smoothbore cannon, which could be regarded as an imitation of the Hongyi cannon, but the blueprint was slightly more advanced.

Liu Yan prepared to imitate the 12-pounder cannon of the French army in the early 19th century, and improved it according to what Liu Yan knew, lengthening the barrel and thickening the barrel.

According to the design, the effective firing range of this gun is two miles, the maximum firing range is three miles, and the weight of the gun body is about 1,200 catties.

At this time, after Cui Mingyuan finished speaking, Liu Yan also came back to his senses and handed over the drawings he had drawn.

Cui Mingyuan hurriedly took it with both hands and looked at it carefully, and the twenty craftsmen next to him also gathered around, and everyone whispered from time to time, and even discussed.

Liu Yan smiled and asked, "What method are you going to use to cast the cannon?" ”

A craftsman immediately said: "Lord Hui, of course I made a clay mold first!" ”

Cui Mingyuan and the rest of the craftsmen also chimed in.

Liu Yan was not very satisfied, and immediately rejected everyone's proposal.

The cannon casting method proposed by Cui Mingyuan and others was also the mainstream method in China and the West at this time, but it was vetoed by Liu Yan. Cui Mingyuan and Qian Jian couldn't help but secretly said in their hearts: "The defense lord really doesn't know how to cast cannons!" ”

In this regard, Liu Yan asked directly: "You use clay molds to cast cannons, what will happen to the moisture in the soil after it encounters high temperatures?" As soon as the molten iron at a high temperature is poured into it, as long as there is a trace of water in the mud mold, it will immediately evaporate in the iron cannon to form bubbles. This bubble is a big hazard of artillery, and it can easily lead to the fragility of the cannon wall and the danger of exploding! ”

Liu Yan is very familiar with the casting technology of this era, so the questions asked are also very professional and tricky, and those craftsmen know that Liu Yan is an insider when they hear it.

Cui Mingyuan, Qian Yan, Tan Xiaoda and all the craftsmen were stunned when they heard this, they didn't expect that Liu Yan, who was a defensive officer, would understand such a professional problem, and glanced at each other: It turns out that the defense master really knows how to cast cannons!

Or Cui Mingyuan replied: "My lord! This clay mold is indeed easy to hide water, so we have to air dry it for a month before using it. However, even so, it is inevitable that some slight moisture will make the copper cannon form a hornet's nest, and under normal circumstances, only one cannon can be used if an average of ten cannons are cast. ”

"A 1 in 10 success rate?"

Hearing this probability, Liu Yan also frowned, obviously very dissatisfied.

So, Liu Yan directly overturned everyone's suggestions and said: "What if you don't use clay molds, but use cast iron as a casting mold?" There is no moisture in the cast iron, and no bubbles will be formed, so the yield will be greatly improved, right? Moreover, the inner and outer walls of the cannon produced by casting iron casting molds will be relatively smooth, which can also reduce the workload of surface cleaning and internal cleaning! ”

Hearing Liu Yan's words, Cui Mingyuan and all the craftsmen were dumbfounded, when they were apprentices, they used clay molds to cast cannons, and they have been making cannons with the skills passed down by their masters for many years, but they never thought of using cast iron to make casting molds.

However, after all, these craftsmen also have rich experience, and after Liu Yan's little stroke, they immediately had a flash of inspiration, and they all felt that it was indeed a good way to use cast iron to make casting molds.

Without the bubbles in the casting process, wouldn't every cast gun be usable? There will never be so many defective products again!

However, at this time, Cui Mingyuan also thought of a specific question, so he asked with a smile: "This idea is very good, but if you use cast iron to make a casting mold, how will this casting mold and artillery be separated at that time?" ”

Liu Yan had actually guessed that someone would ask this question, so he said: "When casting artillery with an iron mold, first brush the inner surface of the mold with a paint synthesized from fine rice husk ash and fine sand mud and water, and then paint the second layer of paint prepared with extremely fine pulverized coal, and then clamp the iron mold, while the gun god is still red-hot, clear the burrs, and you can get the finished product." However, the specific proportion of this paint still needs to be considered by yourself. ”

The method that Liu Yan said was actually recorded in Zhao Shizhen's "Artifact Spectrum" at the end of the Ming Dynasty, and Liu Yan had also read it in detail before crossing over, so it was naturally easy to pinch it.

Hearing Liu Yan's words, Cui Mingyuan and the twenty craftsmen fell silent again, and they silently thought about the method that Liu Yan had just said.

In fact, China is also the first country in the world to use metal model casting tools, as early as the Warring States Period, began to use iron fan to cast pig iron farm tools and tools in batches. The double-layer coating used in iron mold casting mentioned in it is actually an evolution of traditional Chinese casting technology, and it is not even the first one created by Zhao Shizhen, which Liu Yan still remembers vividly.

Some people died, but not completely......