Liu Yu replied without thinking: "Of course you have to control the heat!"
Murong Nan nodded: "Then what is heat and how to control it?"
Liu Yu said with a smile: "As for the heat, it depends on the color of the fire. When it turns green, it happens to be the time when the steel liquid can be melted. At this time, it is usually time to start the pot. I have been watching it a lot recently.
"
Murong Nan continued: "Then do you know what needs to be done to make the fire turn this cyan color? What kind of material should be used to make the fire, and how to set up the furnace and blow the air?"
Liu Yu was slightly startled. He had never cared much about these things. In the past few days in the blacksmith camp, he had only learned to look at the green heat. After asking Murong Nan this question, he began to think carefully about how to make steel these days.
experience.
As he thought about it, he said: "Our stoves are all made of clay, and a special layer of clay is coated inside. It is said that it can prevent the stove from being blown up by the fire, and the hot air discharged from it has to pass through a stone
The pipe is connected back to the furnace to make the fire stronger. As for the blowing, it is to pull the bellows by hand. The person who blows the air needs to be strong and endurance, and often has to pull the bellows for an hour or two at a time.
I have played drums several times, but it is much more tiring than blacksmithing, so I usually have to rotate every half an hour."
Murong Nan nodded: "It is quite good to be able to pour hot air back into the furnace repeatedly and use this kind of closed blast furnace. It seems that the iron smelting technology in the Central Plains is very high. However, have you ever noticed that
What was that fuel that was thrown into the furnace?"
Liu Yu's eyes lit up and he said, "Isn't it just charcoal?"
Murong Nan smiled and shook his head: "It seems you didn't observe carefully. If you just cut down wood and burn firewood, the charcoal can't turn the fire into blue, and it can't make steel. You guys put it right?
What goes in to burn is not charcoal, but graphite, or coal!"
Liu Yu was surprised: "Graphite?"
Murong Nan said seriously: "Yes, this graphite is a black substance buried underground. Only by using it as fuel can the furnace fire turn blue. If only charcoal is used, the most that will be produced is pig iron."
, the color of the fire in the furnace will only turn red, and it will never turn blue, and steelmaking is out of the question."
"Liu Yu, I don't know if you have paid close attention to it. After adding charcoal powder, pig iron and wrought iron become steel. Then these steel blocks have to be re-refined many times to remove impurities. There are many
After the carbon powder seeps out, it will condense into black, small spherical things. This is graphite, or coal."
Liu Yu suddenly thought of the situation of steelmaking. It was exactly the same as what he said. He nodded and said: "You are right. There are indeed such small black particles. Is this graphite?"
Murong Nan smiled slightly: "Yes, this is graphite. Use this graphite as fuel to make steel. Now you should know why the furnace fire turned green."
Liu Yu sighed: "I was still too observant and didn't even pay attention to these. Thank you for reminding me. Is there any way you can make this furnace fire change into other colors besides cyan, and make more refined products?
Will powerful steel come out?"
Murong Nan shook his head: "We don't have this ability. In fact, these things were not discovered by blacksmiths at first, but by the alchemists. In order to make elixirs, they needed the furnace fire to be hotter, so they tried everything in the world, and finally it lasted
, providing such a fierce fire steadily that the only thing that turns the fire green is graphite."
A trace of disappointment flashed in Liu Yu's eyes: "Then since there is no better fuel than the current graphite, how can we make good steel?"
Murong Nan smiled slightly: "Actually, what I want to tell you is not how hot the furnace fire can be made, but how to quickly cool down the extremely hot molten steel."
Liu Yu's expression changed: "Cooling?" His brain was like lightning, and he suddenly thought of the time when he first met Kong Jing. There was a guy who, just to be lazy, did not go to get the mountain spring water in the early morning, but tried to use the river water.
After filling up the numbers, Kong Jing broke one of his fingers.
He nodded thoughtfully: "I understand what you mean. Master Kong takes this cooling thing very seriously, and will even severely punish the servants who fetch water for this. It seems that you are going to do this here
Is the cooling method tampered with?"
Murong Nan nodded: "This is the secret I want to tell you. You Han people will only try your best to make a fuss about the water quality, either using snow melted water, or mountain spring water in the morning, or
Clear streams, etc., but you have never thought that water is not the only thing that can cool everything in this world."
Liu Yu's eyes lit up: "Then what else can be used to cool down?"
Murong Nan laughed: "This is the reason why we Hu people can build elite soldiers and armor. Because we deal with livestock all day long, we can invent the method of cooling the red-hot steel quickly or slowly.
The solution is cow and horse urine and grease!”
Liu Yu opened his eyes wide: "What, can you control the cooling speed with urine and grease?"
Murong Nan nodded: "You can try it yourself. Changing from extreme heat to normal temperature is called quenching. Generally speaking, the colder and icier the water, the faster the cooling speed, but the cooling time is longer.
It’s hard to grasp. After all, water is water after all. Even if the material is different, it won’t be too different. It’s just the difference between fine steel and good steel.”
"But if you control the quenching time and put it in horse urine, it can be condensed into steel after a moment, and if you put it in grease, it can take a night to slowly cool down. What you will get at this time is
It is not ordinary steel, but something between steel and wrought iron. On our grasslands, extremely hard steel is called iron, and this kind of thing between steel and wrought iron
Things called Zhizhirou, now you know where they come from."
Liu Yu laughed, grabbed Murong Nan's hand, and shook it vigorously: "Brother Murong, you have really helped me a lot!"
At the moment when he grabbed Murong Nan's hand, Murong Nan felt as if he was being shocked by an electric shock. He instinctively wanted to withdraw his hand, but Liu Yu's big iron-like hand held it tightly, and Liu Yu couldn't even pull it away.
Yu could even feel that his palms were quickly starting to sweat, and his expression became extremely unnatural.
Liu Yu was a little too excited in his ecstasy. When he saw Murong Nan like this, he also reacted, loosened his hold on his hand, and said with a smile: "I'm sorry, I'm too happy, it's a bit rude."
Murong Nan curled his lips, stood up, and said coldly: "I hope what I said will be helpful to you. I'm leaving. I wish you success."