Just when Su Yuan was full of thoughts, Xu Kui came back with the iron ore, and today he was lucky, he found two pieces of goods with good texture, looked at the strange shape in the master's hand, and said curiously: "Master, what is this thing?"

"You know a fart!" Su Yuan glared at the big black man, and said angrily: "Thing, this is a real baby!"

Xu Kui pursed his lips, and just wanted to say something, Emi Yanagi ran over from a distance, and the bodyguard behind him was holding a few pieces of ore, which seemed to be a small gain.

Su Yuan left with everyone, came to the restaurant to finish eating, and casually asked Xu Kui, "Do you know that there is a sword-forging workshop for sale nearby?"

Xu Kui shook his head and said puzzledly: "Our famous sword villa can forge swords, why do we want to buy a workshop?"

Su Yuan waved his hand, of course he knew that the Famous Sword Villa could forge swords, but he didn't want to expose too many secrets to outsiders, since he had opened the Five Elements Technique, it was safest to have his own territory as soon as possible.

"Don't worry, just leave this kind of trivial matter to Emmi. Emi Yanagi's eyes lit up, and she quickly answered: "I have subordinates around me who are good at collecting information and negotiating, please wait patiently for two days, and there will be results." ”

Su Yuan nodded with satisfaction, this little girl is quite clever, and she is worthy of being a talent cultivated by the Yanagi family, far smarter than the big black one.

Emi Yagyu was happy in her heart, and finally discovered the value of her existence, since she is a master, how can she bother with such miscellaneous things, there are business elites around her, for the Yagyu family, it is just a matter of words.

Quickly stood up, went to the side to call to explain the task, and collected all the properties for sale in Longquan in one night, especially the sword casting workshop, the size does not matter, and the price is not a matter.

Su Yuan put down his chopsticks, asked Emi Yanagi to sit down, and said with a smile: "You go to a place with me tomorrow morning, if you don't guess wrong, there should be a surprise." ”

"Surprise? Could it be ......" Emi Yanagi had a flash of inspiration and said in shock: "Master, have you found the clue to cover the earth and burn the blade?"

"What's so difficult about this!" Su Yuan picked up the teacup and said confidently: "As early as the Han Dynasty, there has been a process of covering the soil and burning the blade, according to ancient records, the recipe at that time was clay + borax + iron powder + toner, the ratio was 1:1, plus charcoal with equal toner content. ”

Borax is a kind of sodium borate sand mudstone powder, which is explained by the current industry to remove surface oxides, so that the clay and the blade are more tightly adhered to, so that it is not easy to fall off when quenched, and it can also prevent the surface of the steel from decarburizing during quenching. ”

Su Yuan looked at the glowing expression of Emi Yanagi's eyes, and wrote lightly: "Steel will change the crystallization method due to the increase in temperature, and when the temperature reaches more than nine hundred degrees, it will become a special crystal, according to your words, it should be called the Ma Tian system, right?"

Emi Yanagi nodded hurriedly, extremely excited, she didn't expect that in less than two days, she would be able to get the coveted clue of the earth-covering burning blade process.

"In our case it is called martensitic, and when it is quenched, the fiery red sword is thrown into water or oil, and the crystals do not have time to turn back because of the instantaneous cooling, and they are fixed. The crystalline characteristics are hard and brittle, and the volume is larger than the original, which is a key factor in the sharpness of the sword. ”

"This is where the texture of the katana comes from, and there are many ways to fold and stretch it, and the common techniques that you have passed down are Kimasaki, Cross, and other ...... such as short books, origami wood, and Konoha "

Su Yuan looked at Emi Yanagi, who was getting more and more excited, and said: "Because there was no high-tech testing equipment in ancient times, the masters rely on experience and feel, and the mystery is not enough for outsiders!"

Yanagi Emi stood up violently, bowed deeply, and said, "Please guide the master!"

Su Yuan picked up the teacup, tasted the tea, and said leisurely: "You call this kind of knife a pill forging or a few dozen things? It's a pity that it can't be used in actual combat." If you want a good blade, you must properly combine steel and wrought iron to form a knife. ”

"Steel is hard and easy to bend, and must be assisted by soft wrought iron, which is soft and easy to bend, and steel must be the backbone, which is called composite blade or sleeve blade. The common combination of samurai blades is triple and rolled. ”

"For the more detailed, the three-piece, four-square, five-piece, etc., are used, and iron is specially added to the easy folding part of the blade. The materials of different materials are integrated through different ancient methods, so that the texture of the whole edge is balanced, which can be described as the best of craftsmanship. ”

"The clay of the burning blade has its own exquisiteness, and different genres have their own secrets. The knife body is covered with soil, and various blade lines appear on the blade and the blade body after high temperature. Different schools of knife workers have different cutting patterns on their knives due to different methods of laying soil. ”

Not only Emi Yagyu, but even Xu Kui listened attentively, and he didn't know much about katana, so today was an eye-opener.

"In my opinion, all sword casting processes basically have the same goal, whether it is the ancient method of oil quenching or covering the soil to burn the blade, it is just the use of high temperature to reabsorb trace elements into the sword and further improve the quality. ”

"Every sword is the same as a person, with different qualifications and different personalities, and it cannot be generalized. Therefore, how to teach students according to their aptitude is the biggest difference between masters and craftsmen. ”

Su Yuan concluded: "Return, retreat, positive, and quenching are veritable four fires!"

The words made Yanagi Emi suddenly open, and many questions about the soil burning blade were solved, and she was pleasantly surprised: "Listening to the master's words, it is really better than reading for ten years, and Emi has been taught!"

"Tomorrow, let's go to the Laoxi waste mine to take a turn, and if we are lucky, we may be able to find the most suitable yellow mud for casting swords, not only covering the soil, but even oil quenching can also be used, that is in line with the true meaning of the five elements!"

Sending everyone away, Su Yuan returned home and cleaned up the meteorite mine with warm water, and sure enough, he found that the soil soaked in water was shining golden and extraordinary.

gold in the mud,

They are the key to oil quenching and mulching!

Su Yuan filtered out the yellow mud, carefully preserved it, and prepared a homemade quenching agent. It is planned to evenly stir the yellow mud into the special grease, and the concentration can be adjusted according to the actual situation, different steels use different concentrations, and different concentrations will lead to differences in the inflection point and slope of the cooling rate curve.

Now I don't have much confidence, after all, I don't have enough actual combat experience, which is also the biggest reason to buy a sword casting workshop. Close the door in the dead of night, you can try a few more times, even if you fail, no one knows, safe and secure.

Now get the meteoric iron, the gold in the five elements has been done, tomorrow I will go to the waste mine to hunt for treasure, the target is the land of the five elements, the treasure of raising the sword hidden in the mud.

Su Yuan carefully studied meteoric iron, there are many legends about strange stones outside the sky in ancient times, according to legend, Qianlong's Nine Dragons Sword was forged with Yingfu, and was buried in Dongling after his death.

Historical records: In the thirty-sixth year of Qin, Yingfu guarded his heart. There is a falling star in the East County, to the ground is a stone, the head of the Qian, or the stone carved is said to be the first emperor died and divided. When the first emperor heard it, he sent the imperial history to ask questions, and he was not convinced, and he took all the people living next to the stone to punish him, because he burned his stone.

When Mars invaded the heart, symbolizing the emperor's disaster, a meteorite fell in Dongjun, and after landing, it turned into a stone, and some people carved the words of the first emperor's death on that stone.

When the First Emperor heard this, he sent the Imperial Historian to inquire from house to house, but no one confessed, so he killed all the people living around the stone and tried to burn the meteorite outside the sky.

As a result, it burned for several days and nights, without any damage, and there was no choice but to find Xu Fu's method, suppress it underground, and later it was dug up by Liu Bowen and dedicated to Zhu Yuanzhang.

The sword is 5 feet, the hilt is long, and nine golden dragons are carved on it, symbolizing the ninety-nine to one. The scabbard is made of precious shark skin and set with ruby sapphires and diamonds, making it a priceless scabbard.

Later, it was stolen by Sun Dianying, circulated several times, and its whereabouts were unknown, becoming a mystery through the ages.