Lin Feng found another five cannon craftsmen and asked them to build a cannon workshop in the city. He wondered how it was going.
When he arrived at the cannon workshop in the east of the city, the furnace had already been built, and five blacksmiths were busy making cannon clay.
Upon seeing them, the five gunsmiths quickly knelt down."Greetings, Lord Defender!"
"No need for formalities!" Lin Feng said. How's your progress?"
"The tools and furnaces have been forged, and we are making clay models to prepare for the first bronze cannon," the five cannon smiths replied. He hadn't made a cannon in a long time, so he was going to make a small one for the first cannon.”
"If you use clay to cast the cannon, what about the water vapor in the soil?" Lin Feng asked after some thought. The moment the high-temperature copper liquid was poured in, even a trace of water in the clay would immediately evaporate into bubbles in the copper cannon. These air bubbles were a huge problem for cannons. They could easily cause the walls of the cannons to become weak and cause them to explode!”
The five cannon smiths didn't expect to know such a professional question. They looked at each other and the chief craftsman Cao Yu said,""Your Excellency is brilliant! Mud models are indeed easy to hide water, so we have to air-dry the mud models for a month before using them. But even so, it was still inevitable that some moisture would form a hornet's nest in the copper cannons. On average, only one cannon out of ten cannons could be used!”
"Only one out of ten cannons can be used? How much useless effort would that take? He smiled and thought of the method of casting cannons that he had learned in the future. He said,"What if we use cast iron instead of clay? There was no water in the cast iron, so it would not form bubbles. The rate of success would be greatly increased! Moreover, the inner and outer walls of the copper cannon produced by casting iron would be smoother, which could reduce the workload of cleaning the surface and grinding the inner chamber!”
Hearing this, the five cannon smiths were stunned. They had been making clay cannons for ten years, but they had never thought of using cast iron to make iron models.
However, they were experienced blacksmiths after all. They immediately reacted and felt that using cast iron to make molds was indeed very beneficial.
Without the bubbles, wouldn't every cannon be usable? There wouldn't be so much waste anymore!
How did this Lord Defender know everything?
Rubbing the back of his head, Cao Yu smiled and asked,""Lord Defender, if we use cast iron as the mold, how can we separate the mold from the copper cannon?”
Lin Feng knew that the Cannon Craftsman would ask this question. He recalled the forging knowledge he had learned in his later life and said,"When casting a cannon with an iron mold, the inner surface of the mold is first coated with a coating made of fine rice hull ash, fine sand mud, and water. Then, a second layer of coating made of extremely fine coal powder is applied. After it solidified, he immediately removed the iron mold and removed the barbs while the cannon body was still red hot.”
Hearing that, the five cannon forgers fell silent, carefully considering Li Zhi's words.
China was the first country in the world to use metal mold casting. As early as the Warring States Period, iron mold was used to cast pig iron farm tools and tools in batches. The use of double-layer coating for iron mold casting was also a common technique in traditional casting. The five cannon smiths had heard of it before. With this reminder, they immediately understood.
After thinking for half a minute, Cao Yu understood and said,
"Your Excellency is brilliant! This forging method is really good!"
Lin Feng accepted the flattery with a smile and explained in detail,"
"First, according to the size of the copper cannon, split it into five sections to make the clay cannon. Then, according to the number of sections of the clay cannon, the iron mold clay model was divided into two sections, and the inner surface was rotated with a car plate to make the surface smooth and neat, and then dried for later use. Prefabricated handles were placed in the clay mold, which were molded into one with the iron mold during casting.”
"When casting a clay mold, first place the muzzle on a clay flat plate and fill one of the halves with mud. After drying, cover the clay flat plate and tighten the mold. After pouring, you will obtain a part of the first iron mold. After removing the mud, another iron mold could be cast. This way, by pouring it section by section, it could be cast into a complete set of iron molds with layers of tenons.”
After listening to Li Zhi's explanation, the other four blacksmiths also understood. They were shocked by Lin Feng's method. Other than reverence, they also looked at Lin Feng with a trace of worship.
My Great Ming Dynasty actually has such a military official!
He then said,"You guys follow my instructions to make the copper cannon first. After it's successful, we'll make the iron-core copper cannon." Iron Core Bronze Cannons were sturdier and lighter!”
There were better techniques?
This Defense Lord knew more than the Frank Machine Gunner under Sun Yuan Hua!
Cao Yu's eyes lit up when he heard this, revealing the craftsman's admiration for technology.
The cannon workshop failed a few times. In the end, under the guidance of the students, they spent 20 days to figure out the technology and successfully made copper cannons with iron billets.. This new method made the body of the copper cannon without honeycomb pores, and the quality was far better than the copper cannon made of clay. Not only did it increase the success rate of casting the cannon, but it also reduced the probability of the finished cannon exploding.
Moreover, the iron billets could be reused, saving casting time. The casting speed was greatly accelerated, and a copper cannon could be forged in three days.
However, Lin Feng was not satisfied with this, so he asked the craftsmen to forge the iron-core bronze cannon. The so-called iron core bronze cannon was to first cast the cannon core with wrought iron. After the cannon core cooled down, it was wrapped in a mold, and a layer of bronze was cast outside the cannon core in the mold.
This method of making cannons was one of the Ming Dynasty's methods, but unfortunately, it was not widely promoted in the original history. At the end of the Ming Dynasty, China's casting technology was not behind the West. During the long war between the Ming Dynasty and the Later Jin Dynasty, there was a need for advanced weapons, and the iron-core bronze cannon came into being. This new type of cannon could withstand higher chamber pressure with less material, reducing the weight of the cannon. At the same time, the melting point of wrought iron was higher and the wear resistance was better, so this technology increased the life of the cannon. Not only that, but because bronze was more expensive, the Iron Core Bronze Cannon saved copper and also reduced the cost of casting the cannon.
He wanted the cannon smiths to use this method to create cannons.
The first type of field artillery he chose was the Minin Light Cannon of this era. It was an 84mm caliber cannon that used a six-pound shell and was two meters long. The direct firing range of this cannon was 4oo meters, the maximum firing range was 32oo meters, and the standard cannon weighed 9oo pounds. However, using the Iron Core Copper Body Technique to cast the cannon might reduce the weight of the cannon by a lot.
The reason for choosing this type of cannon was that the weight and caliber of the cannon were more suitable. In the future, most of the battles they would face would be a combination of infantry and cavalry. Whether it was the Houjin in the northeast or the raiders in the northwest, they were all good at fighting in the wild and rarely defended in Tough City. They did not need heavy artillery that could destroy enemy fortresses, but light artillery that could be used with riflemen in the field.
Under such circumstances, the six-pounder cannon was more suitable.
A cannon weighing 900 jin could be made lighter by using the Iron Core Copper Body Technique. This way, it could be pulled by a carriage and transported more conveniently. Lin Feng also asked them to make a large number of heavy cannons
The cannon smiths had to carry out various experiments and manufacturing, and it would probably take some time before they could produce a finished product that met the requirements. Then, he went to TJ and hired five blacksmiths to the Fan manor. He asked them to be the assistants and apprentices of the five cannon smiths. Then, Li Zhi handed the task to the cannon smiths and went to do other things.
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