There was a coal stove in the blacksmith shop, the fire was blazing, obviously Zhang Laosan was also striking iron just now, and only when he heard their voices did he put down the work in his hand.

Qin Haiqian was a person with a wide range of interests, in order to dig out the traditional folk material processing technology, he once went to the blacksmith shop as an apprentice for a few days, so he knew a little about the tools and rules in the blacksmith shop. He picked up a tongs from the ground, took the shovel that needed to be repaired, put it into the fire, and began to roast it.

"Dude, do you really know how to quench?" The fat man also got in at some point and asked Qin Hai in a low voice.

It was the height of summer, and the temperature in the blacksmith was seven or eight degrees warmer than outside, almost like a steamer. Qin Hai already felt unbearable staying in this room, and the fat man, who was the most afraid of heat, actually got in, completely ignoring the hot sweat on his body flowing like rain, which showed how much he attached importance to this matter.

"Will you strike iron, brother?" Qin Hai didn't answer the fat man's question, but asked a question instead.

"I'm the blacksmith." The fat man replied, "I made all these farm tools." ”

"That's great." Qin Haidao, "The shovel has been curled, and it needs to be forged again, and this matter will be handed over to you." ”

“…… All right. The fat man nodded sneeringly, it is already a great favor that people can help quench, and they can't let people pick up sledgehammers, right?

Qin Hai heated the shovel head to a certain temperature, clamped it out with tongs, and rested it on the anvil. The fat blacksmith also had a few brushes, and he lifted a large hammer beside him lightly, and forged it on the head of the shovel. Because it was only repairing the curly edge, the amount of forging was not large, and the fat man held the hammer and smashed it a few times, and Qin Hai told him to stop.

"Okay, can you quench?" The fat man pointed to a basin of water next to him and said to Qin Hai.

"Not busy." Qin Hai waved his hand and sent the newly forged shovel head back to the furnace to reheat it. His eyes were fixed on the color of the shovel through the fire, waiting for it to heat up to the desired temperature.

"What are you waiting for?" Seeing Qin Hai's serious expression, the fat man couldn't help but be solemn in his heart, and asked in a low voice.

"Heat treatment is not so simple, it is necessary to first heat the metal to Ac3, that is, the temperature at which the free ferrite is completely converted into austenite, to produce solution strengthening, and then take it out and cool it slowly in the air to refine the grains and ......homogenize the distribution of carbides," Qin Hai whispered to the fat man to introduce the introduction to heat treatment.

"This ...... It's too much trouble. The fat man directly rejected the words and deeds of the postdoctoral fellows of the Academy of Sciences, what austenite, grains and the like, are too far away from him, he only cares about one point, when he can see the results after quenching.

Outside the blacksmith shop, Zhang Laosan chatted with the barbarians while peeking at the movement in the house. Seeing Qin Hai heating the workpiece unhurriedly, the teasing expression on his face was slightly restrained.

"What's the matter, third child?" The brute sensed the change in Zhang Laosan's attitude and asked in a low voice.

Zhang Laosan said: "This young man has a bit of discipline......"

"Than you?" He said with a smile, he knew that Zhang Laosan had always regarded himself as a master of craftsmanship, and he liked to brag about himself when he had nothing to do, and now when he heard him say that he was young and had some rules, he couldn't help but take the opportunity to demean him.

Zhang Laosan said insincerely: "Compared with me, he still has to wait 20 years...... I don't understand what he meant by doing that, though......"

At this moment, the short young man who had gone to look for the chemical came back gasping for breath, carrying a cloth bag with several medicine bottles in his hand.

"Hey, what about the one who passed by?" The short man asked the tall man waiting outside the door, Qin Hai had not informed them of his name, so he could only refer to Qin Hai with "passing-by".

The tall man looked at the room with his mouth and said, "Inside, the iron has been struck just now." ”

"I'm coming back late?" The short man was a little depressed.

"It's not too late, it's just the right time." Qin Hai replied in the room, "Did you get anything?" ”

"I've got it all." The short man replied happily that it would be uncomfortable to have traveled so far to find something on this hot day, and if he could not find it back.

Qin Hai had already taken out the heated shovel head at this time, but instead of throwing it directly into the water, he threw it into a pile of ashes next to it to keep it warm. This practice is called tempering and is one of the major processes of heat treatment. Just now Qin Hai said that he wanted to quench these farm tools, in fact, it was just a popular saying, what he wanted to do was to integrate various processes such as normalizing, tempering, and quenching to achieve comprehensive heat treatment of the workpiece.

While the shovel head was keeping warm, Qin Hai took the medicine that the short man had found and began to pour it into the quenching pot next to him. Precise weight control was obviously impossible, so Qin Hai could only rely on experience to estimate the appropriate amount of a medicine, and then pour it into the water to stir and mix.

"Housheng, what are you doing here?" Zhang Laosan had already entered the blacksmith shop at some point, and his curiosity suddenly grew when he saw Qin Hai busy.

Qin Hai turned around and smiled at Zhang Laosan, and said: "I'm preparing a quenching solution, this kind of No. 65 manganese steel needs to be quenched with trinitrate aqueous solution, and the effect is the best." ”

"This is the first time I've heard of this." Zhang Laosan was surprised, "Isn't quenching just water?" ”

"Has Master Zhang ever heard of oil quenching?" Qin Hai asked rhetorically.

"Oil quenching...... I've heard of it. Zhang Laosandao, the so-called oil quenching, is to use vegetable oil instead of water as the quenching medium, and the quenching effect is different from water. Zhang Laosan knew that some iron tools have a better effect of oil quenching, but due to the high cost, they are not used much in practice.

Qin Haidao: "My reasoning is similar to oil quenching. Different materials and different applications require different quenching processes, which involve the use of different media. The trinitrate aqueous solution I use is the most suitable for this kind of steel. ”

"Three nitrate ......" Zhang Laosan was completely frightened by Qin Hai. If you want to say that Qin Hai is wrong, he is right; But if you want to say that he's right, what kind of thing like three nitrate water, Zhang Laosan has never heard of it, could it be that this young man understands more things than himself, an old blacksmith?

"You'll see the effect later." Qin Hai smiled, no longer explaining these problems, the scientific principle of material heat treatment is really not something that a folk blacksmith can understand, of course, this does not prevent these folk blacksmiths from being able to find a heat treatment method that is convincing to material experts with their instinct and years of practice.

Qin Hai took the cooled shovel head off the ash from the furnace ash, put it into the furnace again to heat, and after it was slightly red, he took it out and stuffed it directly into the prepared trinitrate aqueous solution.

"Wow!"

There was a crisp sound of water, and a stream of water vapor rose from the quenching brazier, and all the people in the room smelled a strange smell of sour and salty. Qin Hai soaked the shovel head in water for a minute or two, then took it out, threw it on the ground, and said to the fat man: "Okay, you take out the shovel and let those uncles try the blade." ”

"Really?" The fat man was overjoyed, and he didn't care that there was still some residual heat on the head of the shovel, so he carried it out of the house with his hand.

"Alright, you guys can try." The fat man shouted to several peasants.

"Okay?" The peasant who was called the brute asked, he took the shovel head, looked at it carefully, nodded, and said, "Well, it looks like the color is right." I just don't know if the road is strong or not......"

"Can this shovel really split bricks?" A farmer next to him asked, this is gambling on his anger just now.

"This ......" The fat man was a little lacking in confidence, he didn't know if the statement of splitting bricks was an exaggeration of Qin Hai. The farm tools that have been quenched with great difficulty, if a brick goes down and the blade is curled again, it will be faceless.

"It's okay, let's split." Qin Hai also came out of the house, hugged his hands and said with a smile.

Hearing Qin Hai say it so confidently, he also became curious, wanting to see if this shovel was really as strong and durable as Qin Hai said. He put the shovel head on the wooden handle, then found a half-cut red brick from the side, tapped it lightly with the shovel, and asked Qin Hai: "Housheng, can you really cut bricks with this shovel?" ”

"Cut it." Qin Hai is full of confidence. No. 65 manganese steel is a very widely used material, later generations have extensive research on the heat treatment process of this steel, if such a heat treatment is still put out of the oolong, Qin Hai can directly wipe the neck and wear it again.

He took the shovel and smashed it back and forth on the brick a few times, and then raised it up to look at the edge of the blade, and saw that the edge was intact.

"Slam!"

The bricks shattered into several pieces in response, listening to the crisp sound of the shovel hitting the bricks, except for Qin Hai, everyone couldn't help but grin, thinking in their hearts, this shovel must have a small gap anyway. The brute hurriedly raised the shovel, wiped the remaining brick chips on the shovel head with his hand, and looked at it intently, and couldn't help but laugh: "Ha Luha, there is really nothing at all!" ”

"Let me see!"

"I'll see!"

Several other peasants and Zhang Laosan rushed forward to inspect the edge of the shovel. I saw that in the place where the bricks had been smashed, there was only a faint trace of friction, and there was no damage or curl. Everyone can feel the amount of force used by the brute just now, and it was unscathed under such an impact, which shows the excellent quality of the blade of this shovel.

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In the first week of the new book, the update is a little slower, updating a chapter of 3,000 words a day, and trying to save the manuscript. In the second week, we will strive to achieve two shifts a day. New book issues seek recommendations, clicks, and collections.