Traveling through the late Ming Dynasty to promote Chinese civilization

Chapter 17 Return to Lingao

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In Hangzhou, after explaining the situation at Wanhualou to Suwen, he boarded the Yuanhang ship accompanied by Suwen and others.

"Wait a moment, this is enough," Liu Ye said gently, stroking Su Wen's hair.

"Liu Lang, could you take me to your home sometime?" she asked, looking at Liu Ye with a melancholy expression.

“Sure, if you want to come, I can send someone to pick you up,” Liu Ye said gently to Su Wen.

"Yes, Liu Lang, take care on your journey." Su Wen was very reluctant to let her beloved leave, but she knew that Liu Ye was no ordinary person and was destined for great things. She also needed to manage the Wan Hua Lou well. She dared not leave him in this gentle paradise.

Stepping onto the land of Lingao, Liu Ye took a deep breath of fresh air. He had only been in Lingao for a little over a month after his time travel. Although it was far less bustling than Hangzhou, it was where his career had started, the place where his dreams took flight in another time and space. Returning here felt like coming home.

Li Fu informed Liang Xiaoming of Master Liu's itinerary.

Liang Xiaoming, along with Shi Ying and all the guards at home, happily greeted Liu Ye at the dock. Upon seeing Liu Ye, Liang Xiaoming smiled and said, "Welcome back."

The others shouted, "Welcome back to the mansion, sir!"

The two hadn't seen each other for almost two months and felt an extraordinary warmth, embracing each other tightly. Having gone through life-and-death trials after their time travel and fought together for a common cause, they were now like old friends of many years, not like ordinary acquaintances who had only known each other for a few months.

With the development of Hangzhou Wanhualou, it could earn a gross profit of more than one hundred taels of silver per month, which could be described as a mountain of gold and a sea of ​​silver.

Liu Ye understands the principle that "a common man is innocent, but possessing a treasure is a crime." The Wanhua Tower in Hangzhou is now a goose that lays golden eggs. If it does not have enough strength to resist the covetousness of the outside world, it will sooner or later become meat on someone else's chopping board.

Liu Ye's ambition was to build a fully armed force. Thus, smelting iron, manufacturing guns and cannons was put on the agenda.

Liang Xiaoming was an expert on iron smelting. He told Liang Xiaoming, "Considering the current processing capabilities, wrought iron is used to make guns, and cast iron is used to cast cannons. Specifically, wrought iron is the steel that could be smelted under ancient metallurgical conditions—low-carbon steel; cast iron is an iron-carbon alloy smelted from pig iron, mainly divided into white cast iron, gray cast iron, and malleable cast iron. As for ductile iron and vermicular graphite cast iron, they are completely impossible to produce under current conditions and can be ignored."

The use of technical jargon left Liu Ye confused. He quickly stopped her, saying, "Could you please consider my feelings and explain it in simpler terms?"

Liang Xiaoming smiled and said, "No problem. I'm only responsible for the technical aspects. You can decide which route to take."

He explained these materials in simple and easy-to-understand language. What the ancients called wrought iron is actually low-carbon steel, a type of carbon steel.

Carbon steel is the earliest and most widely used basic material in modern industry. Before the development of alloy steel in the modern steel industry, carbon steel was the earliest material used due to its low cost, wide range of performance characteristics, and largest consumption.

Carbon steel is divided into three types: low-carbon steel, medium-carbon steel, and high-carbon steel. Its properties mainly depend on the carbon content. As the carbon content increases, the strength and hardness of the steel increase, while its plasticity, toughness, and weldability decrease. Therefore, low-carbon steel is easy to process in various ways, such as forging, welding, and cutting. High-carbon steel has the highest hardness, but it is not suitable for shaping and welding.

As for cast iron, ancient furnaces produced white cast iron, which has a low carbon and silicon content, with carbon mainly existing in the form of cementite. Its fracture surface is silvery-white, hence the name "white cast iron." It is prone to shrinkage cavities and cracks. It is hard, brittle, and cannot withstand impact loads. In short, using this type of iron to cast cannons would easily cause them to burst.

Liu Ye digested the information for a moment and summarized, "So, you mean, guns are made of steel, but cannons—which you call casting cannons—are made of iron?"

"Yes, making gun barrels and gun bodies requires materials with good processing capabilities, which means that they can be made by hammering. However, the method of making cannons is completely different. Compared to the light gun barrels, the cannon bodies, which weigh hundreds or even thousands of kilograms, cannot be made by hammering and forging. They can only be cast by pouring molten iron into a pre-made mold."

"Why can't we use the same methods as gun manufacturing to make cannons from wrought iron? Or can we just cast cannons directly from molten steel?"

"Some people also use wrought iron to forge strips and wind them into cannons, but this is not the mainstream method. This method can make small cannons, but not heavy cannons, and it is too time-consuming and inefficient. As for casting cannons with molten steel, let's talk about that after the Krupp company was founded at the end of the 19th century. It's pure wishful thinking now. Even if we could make steel-tube cannons with the current technology, there would only be one outcome—the barrel would explode. Besides, what would you use to process steel pipes? Under the current conditions, what is harder than steel? Are you going to bite it with your teeth?"

"Okay, I think I basically understand the manufacturing method. So let's get back to the material issue." Liu Ye's thinking was clear: the industrial base and manufacturing method determine the choice of materials. "Are low-carbon steel and cast iron difficult to smelt?"

“If we don’t pursue steel with perfect hardness and toughness, and only refine low-carbon steel, the technical difficulty is not high. The Ming Dynasty already had mature wrought iron smelting technology, which is basically just frying steel. The craftsmen are also readily available. All we need to do is optimize the process, improve the furnace, and achieve large-scale mass production,” Liang Xiaoming explained. “However, the material for cast iron is a problem. White cast iron is obviously not suitable for casting cannons, and obtaining gray cast iron is quite difficult.”

Liu Ye asked, "What are the advantages of gray cast iron?"

"White cast iron is too brittle, prone to barrel explosion, and its high hardness and wear resistance make it difficult to process, resulting in a rough and uneven gun barrel and bore. To fire the shell smoothly, the shell diameter must be made much smaller than the gun barrel caliber, which causes excessive clearance between the shell and the barrel, poor airtightness, and a significant decrease in power, range, and accuracy. Gray cast iron, on the other hand, has carbon in the form of flake graphite, a gray fracture surface, low shrinkage during solidification, and compressive strength and hardness close to carbon steel, with good shock absorption. Due to the presence of flake graphite, it has good wear resistance, better casting performance and machinability, and graphite also has a lubricating effect on cutting tools."

Liang Xiaoming thought for a moment: "In terms you can understand, gray cast iron has the advantages of white cast iron—hardness and wear resistance—but without its disadvantages. Cannons cast from it have virtually no cracks, moderate brittleness, and are not prone to barrel explosions. Most importantly, it is easy to process. Cannons can be machined very smoothly with cutting tools, reducing the clearance between the cannon barrel and the shell. The diameter of the shell can then approach the cannon barrel caliber, resulting in excellent airtightness. Its power, range, and accuracy are far greater than cannons made from white cast iron. Do you understand now?"

Liu Ye rubbed his throbbing head. "Is my understanding correct? Cannons made of white cast iron are hard but brittle, prone to bursting, difficult to process, very rough, prone to leaking gas when firing, weak in power, short in range, and inaccurate. Cannons made of gray cast iron are the complete opposite. They are hard but not brittle, very durable, won't burst, easy to process, won't leak gas, powerful, long in range, and accurate."

Liang Xiaoming applauded: "Absolutely right, the comprehension ability of top students is truly remarkable."

"If that's the case, why not use grey cast iron? What are you rambling on about here?" Liu Ye asked, puzzled.

Liang Xiaoming sighed: "It's not that easy. If it were, the Qing Dynasty wouldn't still be using white cast iron to cast cannons during the Opium War. High-quality gray cast iron wasn't produced in large quantities until the 19th century, and Europe still mainly used bronze cannons until the Napoleonic era."

"I've heard of that. Copper was the best material for casting cannons when the iron industry wasn't developed, but copper was expensive, so it wasn't cost-effective. By the way, does Qiongzhou produce copper?"

"The overall copper production in China isn't very high. The Shilu iron mine in Qiongzhou has associated copper deposits, but the output isn't high either. Moreover, in ancient China, copper was a precious metal used to make coins. In Europe, the price of one copper cannon was equivalent to five of the same iron cannons, but in China, it was far more than that. You, a capitalist, are willing to use copper to cast cannons?" Liang Xiaoming mocked him.

Liu Ye naturally objected: "I can't bear to do it; I won't do a losing business."

However, there was another reason Liu Ye didn't mention: he had a long-term plan in mind. Copper was a strategic resource, a precious metal linked to currency, and using it to cast cannons would be a waste of resources. The time wasn't right yet, so he wouldn't tell Liang Xiaoming about this plan for the time being.

Liang Xiaoming was unaware of his ulterior motives; he was simply conducting further technical analysis.

"The key to gray cast iron is silicon. Gray cast iron can be obtained if the silicon content is greater than 1%, while white cast iron is obtained if it is less than 1%. The furnace temperature is the key to reducing silicon. Gray cast iron cannot be obtained if the furnace temperature is lower than 1500 degrees. However, the temperature of the traditional charcoal ironmaking furnace will not exceed 1300 degrees, so only white cast iron can be obtained."

Liu Ye cut to the chase, asking, "So how do we increase the furnace temperature?"

After careful consideration, Liang Xiaoming tried to banish the image of a modern steel production line from his mind and replace it with a blast furnace from the 17th or 18th century. After taking various factors into account, he cautiously answered Liu Ye's question.

"Since there is no steam engine, the way to increase the furnace temperature is to use coke instead of charcoal, build a regenerator, use water power instead of a steam engine for blowing, and adopt preheating blowing technology. This should be able to produce gray cast iron with a high silicon content. Technical problems such as regenerators and blowing can be gradually overcome through practice, and there are no major problems."

"But the coke problem is quite troublesome. Qiongzhou only produces lignite, which is a low-quality coal with a very low degree of coalification and is not suitable for coking. Coking generally uses bituminous coal. China's largest bituminous coal producing area is in Shanxi, but it is too far away from us. Among the coastal provinces, only my hometown Shandong has a considerable bituminous coal production, but it is still too far for us to reach. The Ming Dynasty would not allow us to mine coal there, as it was still the heartland of the court and very close to Beizhili."

Liu Ye's thoughts: "You'll handle the technology, leave the implementation to me. But are you sure we really have to go all the way to Shandong to mine coal?"

Liang Xiaoming shrugged: "Guangdong also produces coal, but the reserves are too small, and it's not a shallow deposit. With our technology, we can't find it. Shandong has several coal mines that are easy to explore and mine, so..."

Liu Ye clapped his hands and said, "I understand. The Shandong matter can be included in the long-term plan. Let's talk about the present. Can't we make cannons without coke? If we don't have Zhang the butcher, do we have to eat pigs with hair on?"

"There is a solution, which is to graphitize and anneal the white cast iron. This involves slowly heating it and then cooling it at a controlled rate to obtain malleable cast iron, which Europeans call malleable cast iron. It has better plasticity and toughness than gray cast iron, and its hardness and toughness are close to those of high-quality carbon steel. Moreover, it is easier to process than steel..."

Liu Ye was bewildered: "I'm a bit confused, let me sort this out. You mean that you can just burn that kind of garbage white cast iron and it'll be better than gray cast iron, and even have properties close to steel? Holy crap, then why bother with all that effort to make gray cast iron?"

Liang Xiaoming felt wronged, explaining to laymen that it was indeed this complicated: "Although the malleable cast iron obtained by this method is of good quality, its implementation is very limited. It is only suitable for relatively small and simple castings, with a wall thickness not exceeding 100 mm, and generally around 80 mm is ideal. It is first cast from white cast iron, and then placed in a large processing furnace for annealing. The annealing time is very long, and the efficiency is not high. It is only a transitional method before the advent of gray cast iron. This method cannot be used to manufacture naval heavy artillery, but it can still be used for small-caliber field guns."

"Damn, what a disappointment. It turns out all they can do is build small cannons." Liu Ye expressed his disdain.

He summarized Liang Xiaoming's words: Manufacturing guns—they could utilize existing steelmaking technology; manufacturing cannons—heavy cannons could only be forged with coke, currently only small cannons could be forged. The immediate priority was to solve the problem of having enough, only then could they focus on solving the heavy cannon problem. As for the current slow and inefficient forging small cannons, it wasn't a major issue; they could wait. Once they had guns, they could deal with most of the opponents they might encounter.

So Liu Ye made the following decisions: First, immediately launch a steelmaking or low-carbon steel project; second, after obtaining qualified low-carbon steel, build an arsenal to manufacture guns; third, use annealing technology to produce small-caliber cannons; and fourth, include coke and the development of Shandong in the long-term plan.

Liang Xiaoming chuckled, spreading his hands. "Capitalist comrade, you can just talk the talk, but where are the people? You need to give me a few blacksmiths, right? This is a skilled trade, unlike weaving where you can learn it in half a day. Then you'll have to go to Guangzhou to buy pig iron. We haven't mined any iron ore yet, so we can only buy ready-made iron."

A capitalist glared at him fiercely: "Wait, even if I have to kidnap someone, I'll kidnap a few blacksmiths for you. As for the rest of the workers, you can train them yourself. Meeting adjourned!"