Last heat.

When Bi Fang took the steel bar out of the blast furnace, his whole body trembled.

Exhausted or excited?

Or both?

I can't tell, at the moment of harvest, all suffering turned into the sweetest fruit, and all kinds of flavors are in it.

The dazzling metal in front of you can no longer be called iron, but steel!

Stronger, stronger and sharper!!

Taking a deep breath, Bi Fang eased the dizziness caused by overwork, and the familiar wooden handle was firmly held in his hand, and the force rose from one point, fell from a height, and slammed heavily on the steel bar.

There is no longer a black iron sheet falling, and all impurities are approaching the limit of manual removal.

Under force squeezing, the bright orange steel is squeezed little by little, deformed, and becomes flat and narrow.

The rudiments of the dagger have gradually appeared.

But steel is far less easy to build than iron.

Whether it is hardness or toughness, or the ultimate sharpness, steel is far better than iron, and the same is true for tempering.

There was not enough time for Bi Fang to do so, the sun was high up, and it was about nine o'clock in Mo, and he went out to eat and rest, leaving him with less than six hours to forge forge.

There is really a sense of tension in participating in the Broken Knife Competition.

"In order to make a working dagger today, I don't plan to cut the blade, there is no cutting machine, if you want to open the blade, you have to use a whetstone to sharpen it, as long as the ghost has to sharpen it."

"So I'm going to make a double-edged dagger, without a blade, but the tip can be stabbed, which is also practical, and besides, our steel is just the most ordinary steel in the end, and no one knows how strong it is, and it can make up for the strength with thickness without cutting the edge."

Cutting the edge will inevitably cause the edge to become thinner, and Bi Fang does not have much confidence in the strength of the blade he has created, worrying that it will easily cause a chip.

Heating, forging, heating, forging.

The sun rises in the east, shifts to the south, and has a tendency to move westward.

After eating the mushroom rabbit broth, Bi Fang put his hands in the puddle and soaked for a while, regained some energy, and added the red dagger.

Yes, Dagger.

After almost six days of hard work, at noon on the last day, the prototype of the dagger finally appeared.

The slender iron handle was finally glued to the wooden handle, and the blade was more than twenty centimeters long, like a bayonet, but it was too thin, and the ridge was so thick that it was clearly not fully unfolded.

Bi Fang replaced the sledgehammer with a smaller, more controllable one, and thrashed it finely and evenly.

Bi Fang's face was red by the dazzling fire, and the charcoal in the blast furnace had not been heard from yesterday early morning until now, and it had been burning, adding a bit of frenzy to the hot rainforest.

【Swordsmith!】 】

[When did LOL come out of the hero of the old side, wild hunter, part-time sword casting, it is best to position the jungle! 】

[I think so]

[This muscle, I call it the sexiest man, no problem, right?] 】

[I also think it's okay]

[10,000 people petition! I'll buy it when the skin comes out! 】

The hard steel bar was once again stretched, from slender to narrow, extending from the spine to the sides, and the top became more and more sharp, and everyone had no doubt that this knife was enough to pierce the entire human body.

It's metallic steel!

What wooden spears, bone spears, and metal steel are all weak and explosive!

At three o'clock in the afternoon, the light was still good, and the dagger had changed drastically again, and it really had the appearance of a knife.

Bi Fang cocked the dagger and crouched down to examine the lines on each side.

The shape is not exaggerated, just like the usual double-edged daggers, but this is completely freehand refining in the absence of anything!

Bi Fang from any face, the lines have been done to the limit of manual work, the spine is straight and even, the blade open to both sides is uniform and smooth, the tip of the knife is sharp and shapely, anyone who looks at it has to praise this is a sharp blade.

[Damn, I haven't watched it for two hours, and it's changed so much]

[As if it wants, woo woo]

[Unlock Achievement: Coming Hard]

【Unlock Achievement: Kirin Arm】

[Hey, there are still three hours of live broadcast to end, I don't know how long I will wait next time]

[It's mid-June, at least July, right?] 】

Bi Fang clamped the steel dagger with wooden tongs to heat it one last time, and at the same time, added a large amount of sand under the furnace bridge, this step was so fast that the audience didn't see it so clearly, only when Bi Fang stuffed a handful of strange ash into it.

Then comes the final step.

Quench.

This time, Bifang removed the blower, otherwise the heating temperature would be too high.

"There are four basic processes for steel heat treatment: annealing, normalizing, quenching and tempering. It is also the 'four fires' in the overall heat treatment, in which quenching and tempering are closely related, and are often used together, all of which are indispensable. ”

"I won't talk about annealing and normalizing, I won't use it next, mainly tempering and quenching, maybe more people have heard of quenching, what I usually see is freshly heated metal, into the water, smoking."

[I often see it on TV]

[I've seen it]

[Tears of engineering materials, this course is too difficult, iron-carbon phase diagram alloy phase diagram]

[I don't want to listen to it, I'm going crazy]

"Hahaha, engineering materials are really hard." Bi Fang himself has a headache of learning, and what he knows is not all given by the system, and a lot of knowledge is taught by Bi Fang himself.

"The heat treatment process of metal heating, austenitization and cooling in an appropriate way to obtain a martensitic or bainite structure is the so-called quenching, the most common are water cooling, oil cooling, air cooling, water cooling is what you just said, put it in the water, and cool it down rapidly."

"We don't have so much oil, the only choices we can choose are water cooling and air cooling, and different cooling materials will change their properties differently."

"In order to reduce the brittleness of steel, the quenched steel is kept warm for a long time at an appropriate temperature higher than room temperature and lower than 710 °C, and then cooled, which is tempering."

Bi Fang opened the lid of the furnace and carefully observed the color of the dagger.

"This is the last step in the production of daggers, we first have to burn the dagger to red, remember, it can only be red, do not turn white, that is, the orange-yellow stage, the white knife is very easy to deform, and too brittle, what kind of temperature is the specific, you can find the steel heating color map on the Internet."

Seeing the right time, he took the reddened dagger out of the furnace, Bi Fang clamped it on the blade, took it to the basin of water, and did not stuff it at full speed, but put the blade in, and the high temperature touched the cold water, and the flames burst out in an instant.

[, will it catch fire? 】

[Water catches fire? 】

[Water decomposes at high temperatures to produce hydrogen and oxygen, and then burns at high temperatures. That's why in a very hot stove, a little water is more conducive to combustion. 】

[What kind of fart, sprinkling water to fuel combustion? You don't consume as many calories, do you? 】

[Wrong, delete it, quenching will burn because it is not water that is quenched, but oil, and water droplets will burn in the furnace, because water and carbon produce hydrogen and carbon monoxide under high temperature conditions, which is called water gas, read more books, and install less ×]

[Where did the number one come from?] See clearly, this is oil? 】

[Why don't you ask the magic old recipe?] 】

Bi Fang didn't have time to answer, the actual quenching and rhythm had to be grasped well, and the blade was soaked in water for only two or three seconds, and he changed his face again, and a ball of flames burst out again.

Under the photography of the drone, the audience saw that a layer of oxide film was directly peeled off on the surface of the blade, which was still brownish yellow.

"In addition to water quenching, you can also use oil to cool, just use waste engine oil, diesel gasoline I don't think there will be warriors to quench, right?"

"As for the oil quenching process, it is basically the same as water quenching, heat it to red and immerse it directly, wait until the waste engine oil is no longer bubbling, and use a stone or sandpaper to polish off the iron oxide on the quenched knife, and then you can temper it."

After that, Bi Fang kept repeating this process until it no longer faded, and then sent it into the furnace again for insulation and tempering.

This time, the audience found that Bi Fang no longer put the knife into the flames, but opened the fire pit, sent a dead leaf into the sand pit, and when he saw that it became charred but not black and did not burn, he directly sent the dagger into the sand under the furnace bridge.

Then he sprinkled some water on the charcoal fire on the bridge and doused it, sending out billowing steam.

What the heck?

At this time, Bi Fang saw the audience's quarrel, flipped over the barrage, and said with a smile: "It's true that the varnish is burning, but it's not right, it's not a simple high temperature that can directly decompose water, it is the high temperature gasification of water and then the reaction with red-hot iron to generate ferric tetroxide and hydrogen, and the high-temperature hydrogen comes into contact with the oxygen in the air and immediately spontaneously combusts." ”

"Didn't you just see a layer of film peeling off? That is ferric tetroxide. ”

Audience: "......"

Co-authored white quarrel?

[I just said that high temperature can't directly cause water to decompose!] 】

[Pull it down, hindsight]

[Bullshit! 】

[So what did Lao Fang do just now? So extinguished the furnace? 】

"Tempering, no matter what kind of quenching method, it must be tempered afterwards to make the steel more stable and tough, I use the sand burning method."

Bi Fang sat on the ground and used a stick to shake the sand under the bridge.

"The tempering temperature is far from being so high, but the temperature is not easy to confirm, the best way is to heat the sand, and when you feel almost, you can have a leaf that is not so dry, or a piece of paper, when the paper becomes brown but not black and does not burn, the temperature is the appropriate tempering temperature."

Bi Fang pulled out the leaves that had just been thrown in, and sure enough, the surface was brownish-yellow, but it was not blackened or even burned.

"At this point, bury the knife in the sand, let the fool and the blade cool down, and the backfire is complete, and we have a dagger that has been finally formed, of course, it still needs to be sharpened a little."

After saying this, Bi Fang felt relaxed, and his whole body collapsed on the ground, and every muscle let out a wail.

It's so tiring.

However, it was finally done.

Steel dagger!