79: Chapter 79 The Shock of a Level 4 Blacksmith

Hu Gualing thought about the gray-quality bracer in the game; when he crafted that bracer, there was also charcoal in the furnace.

In other words, that bracer had actually undergone Carburizing.

But even so, the result was only the trashiest gray quality, and the effect when worn on the hand wasn't great either. If he were to use that bracer to block the blade in Zhang Zhongqing's hand... I'm afraid the bracer would snap even more cleanly than the iron stake used for testing!

Hu Gualing looked at the steel blade in Zhang Zhongqing's hand with envy in his eyes and couldn't help asking, "Teacher Zhang, did people in ancient times have any way to improve the effect of Carburizing?"

"Naturally, they did. However, to understand this, you must first understand Carburizing media."

"Carburizing media?"

"Correct. Carburizing media can decompose to produce active carbon atoms, and these active carbon atoms can be better absorbed by the casting to achieve a better Carburizing effect."

Seeing the thirst for knowledge in Hu Gualing's eyes, Zhang Zhongqing revealed a kind smile. It was as if he had returned to the classroom, treating Hu Gualing as his own student and explaining in detail.

"Common Carburizing media include methane, ethane, benzene, alcohol, acetone, acetylene, silicon carbide, graphite, cyanate, nitrogen... Of course, charcoal added with an accelerator can also count as a Carburizing medium. When my vacuum furnace was performing Carburizing just now, I used high-purity acetylene."

Listening to Zhang Zhongqing rattle off a string of chemical terms as if they were his own family treasures, Hu Gualing's head started to spin. Hearing the end, he couldn't help but feel a bit disappointed, "Teacher Zhang, I'm afraid ancient times didn't have any of the things you mentioned..."

"Why wouldn't they?"

Zhang Zhongqing suddenly said something very philosophical: "Many things have always existed; we humans merely discovered them, not created them."

Hu Gualing was dumbfounded, "You mean... these things existed in ancient times?"

Zhang Zhongqing nodded slowly, "Take the simplest example: charcoal and accelerators were just plant ash and mud in ancient times. For instance, over in the little Japanese nation, when Forging Japanese swords, they would use paper combined with plant ash and mud to wrap the casting, then precipitate carbon black through Forging."

The little Japanese nation? Hu Gualing had no affection for this country, and the matter of Wu Yingying being attacked was inseparable from the people of the little Japanese nation, so he couldn't help but frown when he heard these three words. "Then... how effective is this method from the little Japanese nation?"

Zhang Zhongqing smiled disdainfully, "This method is mainly characterized by low operational difficulty, and the required Materials are simple. As for the effect, it's better than nothing, but it falls far short of our ancient Chinese Carburizing technology."

Hu Gualing perked up immediately and asked with great interest, "Then how did we in ancient China perform Carburizing?"

"According to the records of 'Tiangong Kaiwu', in ancient China, we would put the casting into a large pot, then place charcoal, fermented soybeans, and mud on top of the casting, heating and stewing it as if making a pot of soup. Both charcoal and fermented soybeans contain carbon atoms, while mud acts as a dispersing agent. Used together, the resulting Carburizing effect is quite good, and this technique is still in use today; it is called the 'Stewed Steel Method'."

When speaking of the things from the Old Ancestors, Zhang Zhongqing's expression was filled with a sense of pride.

However, just as he was speaking, he saw Hu Gualing suddenly take out his phone and start fiddling with something on it with a focused expression. He couldn't help but feel dissatisfied and leaned over to take a look.

Upon looking, he realized that Hu Gualing was typing to take notes, and was even muttering to himself, "Stewed Steel Method, charcoal, fermented soybeans, mud..."

Seeing this scene, Zhang Zhongqing was moved. So, this child was taking notes; he had almost misunderstood him...

Teachers always like children who love to learn, and Zhang Zhongqing was no exception.

Seeing that the things he mentioned casually were so highly valued by Hu Gualing, he felt a little touched. He paused slightly to wait for Hu Gualing to finish writing, then continued, "Besides this, there is also a method similar to Japanese sword Forging, only the Materials are replaced with soybean paste and saltpeter. The properties of the soybean paste are the same as fermented soybeans, while saltpeter contains nitrogen. Applying these two Materials to the casting and heating it is the prototype of Carbonitriding technology..."

"Additionally, there are animal fur, grease, and ox/sheep horns. These things all contain nitrogen and can lower the critical temperature of steel, making them very important Carburizing media in ancient times. The record in 'Wuyue Chunqiu' regarding the famous sword Ganjiang says that 'the essence of metal and iron could not be melted', so hair, fingernails, and a large amount of charcoal were added during the Forging process. The final product was a steel weapon, which is why it could cut through iron like mud. However, the so-called iron at that time was actually bronze, which is far less hard than real iron. If you stabbed hard with a sword made of bronze, the tip would bend, and it would need to be placed under the foot and stepped on to straighten it before it could be used again. Even so, one still has to admire the wisdom of the ancients..."

While Zhang Zhongqing was sighing with emotion, Hu Gualing was typing rapidly on his phone: soybean paste, saltpeter... grease, ox/sheep horns... After finishing his notes, he looked at Zhang Zhongqing with eager eyes, "Teacher Zhang, is there more? What if I want the effect to be even better?"

"How good of an effect do you want?" Zhang Zhongqing asked casually.

Hu Gualing glanced at the alloy steel blade in Zhang Zhongqing's hand and swallowed. He knew that with ancient conditions, he certainly couldn't reach the effect of this low-alloy steel blade. However, if he could have two or three tenths of the power of this blade, it should be enough for the game. So he said, "If I could achieve two or three tenths of the quality of your blade, that would be perfect."

Hearing this, Wu Yingying was suddenly a bit puzzled.

It was one thing for Gualing to be interested in blacksmithing, but why was he paying special attention to ancient blacksmithing techniques, even writing down every detail the teacher mentioned? And listening to what he said, it seemed like he wanted to forge it himself?

Wu Yingying thought about it and could only attribute this to a special hobby... just like the teacher, who leaves various equipment unused and insists on manual Forging. Perhaps this was the reason why the two of them hit it off so well.

Zhang Zhongqing was in high spirits and didn't think much of it when he heard Hu Gualing ask this. He smiled and said, "Given the basic conditions of ancient times, reaching two or three tenths of the standard of a low-alloy steel blade is quite difficult. I can only say there is one Forging technique that can make the quality of the finished product relatively close to modern craftsmanship."

There really is such a craft? Hu Gualing's pupils constricted, and he couldn't help but prick up his ears to listen to Zhang Zhongqing continue:

"This craft is the famous 'Pouring Steel Method'. It is recorded in great detail in 'Tiangong Kaiwu'. Pouring Steel, as the name implies, is to pour the Carburizing agent onto the surface of the casting to perform Carburizing. And this Carburizing agent is ingenious; it is not something else, but precisely iron."

"Iron?" Hearing this, the Level 4 Blacksmith Hu Gualing showed an incredulous expression. This was completely beyond his understanding.

Zhang Zhongqing smiled, "Using iron to carburize iron—this is exactly where its ingenuity lies. During the Forging process, one first forges wrought iron, then melts pig iron into molten iron and pours it onto the wrought iron. For example, the 'Book of Northern History' records the Forging process of the Sutie sword: 'Burn pig iron essence to layer onto soft ingots; after several nights, it becomes steel.' This is using pig iron as a Carburizing agent. The final product is a steel blade in the modern sense."

Hu Gualing was stunned for a moment, and it took a few seconds for him to realize what was going on. He quickly wrote down this Pouring Steel Method on his phone and simulated the Pouring Steel process twice in his mind. Confirming there were no other issues, he asked, "What about quenching? Does such an ingenious Carburizing method also have a unique quenching technique?"

"What other techniques could there be for quenching? It's nothing more than using a different cooling liquid. Like the aviation oil I use, it's a single-liquid oil quench." Zhang Zhongqing said, pointing his sword at the bucket of red liquid.

"However, ancient times naturally didn't have these conditions; using vegetable oil as a substitute would suffice."

This time, before Hu Gualing could even ask, Zhang Zhongqing stated the substitute Material.

Hu Gualing's eyes were full of gratitude. He thought to himself that Zhang Zhongqing was truly a professor; even though blacksmithing was just his hobby and not his profession, he could explain it clearly. With this knowledge, when he re-entered the game, he would be able to craft several powerful pieces of equipment. Leaving the village to fight monsters would definitely be a piece of cake...