Great Power Industry: You're a private company building an aircraft carrier?

The hydraulic press has been purchased, but there's one last step before it can be used: the mold.

A mold is placed on the worktable below the hydraulic press. This mold is usually recessed. A second mold is placed below the movable beam above. This mold is usually convex.

As the movable beam moves slowly down along the four pillars under the action of the hydraulic cylinder of the top beam, the upper mold slowly moves down to the lower mold, and finally the two molds are tightly joined together.

During stamping, the material to be processed—usually steel plates—is placed on the hydraulic press worktable, and with a clang, the upper and lower dies process the steel plate into the corresponding shape.

Not only is the processing fast, but the finished products also have a high degree of consistency.

The outer shell of the old Jiefang trucks was hammered out by experienced craftsmen, so each one was different and could not be interchanged. Later, stamping parts were used, which greatly improved the consistency of the products.

The processing quality of a hydraulic press depends on both the pressure and the mold.

The higher the precision of the mold, the higher the precision of the pressed parts; the harder the mold, the harder the materials it can process.

The principle is simple: you need to be strong yourself to succeed!

If the hardness is insufficient, the hydraulic press will bang, the steel plate will be fine, but the molds on both sides will deform.

Therefore, mold manufacturing is very complex. It generally uses high-strength steel, such as high-carbon steel or alloy steel, and is then machined on a lathe. To machine this type of steel, the tools required must be of even higher strength. In later generations, CNC machining centers were also used to improve precision.

Moreover, it's not something that ordinary people can make; there are specialized mold factories that are responsible for processing it.

I've never heard of using casting to process molds! Isn't that nonsense? Castings have low strength and poor precision, so they can't be used as molds at all!

Qin Jianguo led everyone over and saw Qin Chuan helping Li Jianshe organize the sand mold.

I made this yesterday, and it's dry now, so it's ready to use.

Judging from its shape, it was clearly intended for use in casting gas cylinder molds.

"You want to make stamping dies? Ogawa, stamping dies aren't cast!"

"I know," Qin Chuan nodded.

"Then what are you doing?"

"Making molds, huh? I've inquired around, and the only mold factory in the north is in Tianjin. The price is 200,000 yuan. Money isn't the problem; the key issue is that the orders are already booked until next year. If we don't make them ourselves, are we supposed to wait until next year?"

Li Runping was stunned for a moment, and looked at Zhao Shuren with suspicion. Didn't you just say you wanted 500,000?

Zhao Shuren's expression froze. Pan San spoke up from the side: "Different molds require different steels. The ones my master arranged for you are definitely the best steel. Even if they are more expensive, they will have less wear and tear and a longer lifespan. Those costing 200,000 yuan will only last for two years at most. The ones we arranged will last for ten years without breaking down."

"That's right!"

Zhao Shuren nodded quickly: "Steel is the most important material. If you use ordinary steel to cast the mold, it will deform and become unusable after at most six months."

"Xiao Chuan, I've already started the furnace and thrown in all the scrapped molds!" Just then, Zhang Wanhe ran over.

When unloading, most people only noticed the large wooden box. In fact, there was also a small wooden box on the truck. When Qin Jianguo led people to install the hydraulic press inside the large wooden box, Qin Chuan asked Zhang Wanhe to take the small wooden box to the steelmaking furnace and start smelting.

The small wooden box was full of discarded molds. Although they had been cut in half, their original outlines were still visible. Some were cylinders, and some were cones...

Regardless of what it was used for before, once it becomes molten steel, you can no longer tell the difference.

"Ahem." Zhao Shuren coughed twice: "Director Qin, Lao Li, since you invited me here to guide your technology, I have to do my duty. I have to remind you that after the mold steel is melted and recast, it cannot reach the original strength."

Can you achieve the same strength by melting down and remelting steel? Are you kidding me!

After being remelted, the quality of the steel will drop by one grade. Even if the composition of the steel remains the same, the internal structure is not the original structure, and the strength will not meet the requirements!

"That's right. After steel is smelted, it still needs to undergo heat treatment in order to become various usable parts."

Pan San said, "This advanced technology of heat treatment is not something a small steel mill like yours can master!"

“We understand heat treatment,” Qin Jianguo said. “The main processes are quenching and tempering. Quenching can increase strength, and tempering can increase toughness.”

Don't underestimate us just because we're a small county-level steel plant. Our master craftsmen came from Shougang Group. Don't you understand?

We can all use the technical terms: When steel is heated above its critical temperature, its interior transforms into austenite, and then through rapid cooling, it transforms from austenite into martensite. Among all steel microstructures, martensite has the highest hardness.

However, Qin Jianguo is rather reserved and doesn't like to show off.

“Really? Then you guys go ahead and build it! We’ll wait until the mold is finished, then we can start working,” Pan San said.

Zhao Shuren frowned.

"Let's go, move the mold over to the steelmaking furnace!"

With everyone busy, Zhao Shuren and Pan San fell behind.

"They're going to quench it; I'm afraid something might go wrong!" Zhao Shuren said slowly.

"That's a must. They only realize that acting recklessly won't work when something goes wrong, and then they'll have to ask us for help."

Pan San said, "Hmph, what do they know about quenching processes? They just throw the molds into the water tank, and they'll definitely explode!"

When our ancestors were making weapons, they discovered that by heating the weapons, which had been forged through countless hammer blows, to a certain temperature and then throwing them into water, the hardness of the weapons could be greatly increased. They called this method quenching.

Over thousands of years, this has created a fixed impression among ordinary people: What is quenching? Heating it and throwing it into water!

However, quenching can also create internal stress in steel, and if the cooling is too rapid, the steel will twist and deform, or even crack.

Especially now, these two gas cylinder molds are just two lumps of iron.

It's so thick, if you heat it up and then put it in cold water, it'll definitely explode!

Zhao Shuren was still somewhat worried.

"Master, we've already offered to help them purchase the molds, but they didn't agree. They act like we're making a huge profit off them. How can we not make them suffer a little loss..."

"Give me, let me!"

Just then, a tricycle appeared from behind, carrying... an oil drum!

Zhao Shuren sniffed: "Diesel? They're planning to use oil for quenching?"

Actually, the earliest quenching agent used was vegetable oil. Compared with water, its biggest feature is that it is more gentle. Hot steel will cool down immediately when it enters water, but it will take longer to cool down when it enters oil, and the cooling speed is slightly slower, so it is less likely to cause the steel to break apart.

In modern heat treatment processes, oil quenching is also very common. Mineral oil is the most commonly used, and different mineral oils are selected depending on the type of steel being quenched, while some special additives are also added.

Do the people here even know to use diesel fuel as a quenching agent?