Siheyuan: Craftsmen of a Great Country

From the moment the molten pig iron began to be poured in, everyone's eyes were focused on the converter.

In addition to expectations, you must also promptly detect possible abnormalities and be ready to terminate the experiment at any time.

After all, the experiment can fail countless times, but any accident may cost the lives of workers participating in the experiment.

When all the molten iron in the container was poured into the converter, Su Changming began to issue startling instructions:

"Straighten the furnace."

Due to insufficient intelligence, although this work is assisted by machinery, it still requires manual control.

The worker carefully controls the operating lever in his hand to adjust the inclination of the furnace body.

When the marking line on the furnace body is aligned with the reference line, it means that the furnace body is now vertical to the ground.

At the same time, this time cannot be too long, because the temperature of the molten iron in the furnace will gradually decrease.

"The furnace body is vertical." The worker reported loudly.

After Su Changming stepped forward to check that everything was correct. He said loudly: "Close the furnace lid and lower the oxygen gun."

The heavy furnace cover is slowly closed to maintain the airtightness of the converter and reduce heat loss.

The porous oxygen lance made of special materials begins to gradually descend, preparing to blow in oxygen.

As the oxygen gun lowered, the atmosphere at the scene solidified.

Whether steelmaking is successful, whether an accident occurs, and when oxygen is blown in are the most critical nodes.

Su Changming's palms were full of sweat and he kept wiping them on his clothes.

To avoid slippery hands when controlling oxygen input.

The hearts of the several operators standing nearby were beating fast.

Su Changming took a deep breath: "1 atmosphere pressure, 60% dehydrated oxygen blown in, timely temperature detection, report every five seconds."

Hearing this, Lu Yuehua clenched his fists. He was responsible for the oxygen part.

The reason why we start from 60% is still based on safety considerations.

Because everyone is worried that if the oxygen content is too high, the reaction will be too violent and it will cause an explosion.

If the temperature rises too slowly and the reaction speed is not enough, the oxygen content can be continuously increased.

Temperature is the most important parameter for successful steelmaking.

Jiang Chen was not worried at all, because he was the only one who knew that real industrial oxygen for steelmaking generally requires a purity of over 99.5%.

This is only 60%, it’s drizzling.

"Temperature 1260"

"Temperature 1320"

"Temperature 1390"

"Temperature 1460"

With the input of oxygen, the furnace temperature, which was already low, began to rise rapidly.

What followed was a huge noise.

It shows that a violent chemical reaction is taking place on the surface of liquid pig iron, and iron, silicon and manganese are oxidized.

"Temperature 1500."

"Temperature 1510."

"Temperature 1518."

Su Changming said loudly; "The temperature increase rate is slowing down, and it is expected that it will be difficult to meet the temperature requirements."

For steelmaking in a converter, the temperature is required to be above 1600 degrees, but now the temperature is still nearly a hundred degrees lower.

At the current rate, it is indeed difficult to reach the set temperature.

Lu Yuehua and Jiang Chen looked at each other.

Jiang Chen said directly: "Lower the gun and increase the oxygen content to 80%."

Su Changming executed without hesitation: "Lower the gun and increase the oxygen content to 80%."

Lu Yuehua whispered: "Director Jiang, an increase of 20% at once is too big a span."

He also did it for safety reasons.

Jiang Chen said: "The temperature is not enough now. If we don't adjust quickly, if the temperature is still not up to standard after the relevant substances inside have reacted, the experiment will be considered a failure."

Knowing that this content was safe, he directly increased the oxygen content by 20%.

In fact, before the experiment, he knew that this steelmaking was bound to fail.

Because it has not been sprayed with ferrosilicon powder to increase silicon, there is not enough material that can provide heat.

"Temperature 1530."

"Temperature 1542."

"Temperature 1550."

"Blow in 90% pure oxygen." Jiang Chen gave the order again.

But the increase in temperature is still unthinkable.

One step away from 1600 degrees, but still unable to reach it.

"Lower the gun again and blow in 95% oxygen."

"98% oxygen blown in."

"99.5% oxygen blowing"

Jiang Chen continued to adjust the amount of oxygen injected.

"The temperature is 1600 degrees, which meets the minimum requirements."

"The temperature is 1620 degrees."

"The temperature is 1640 degrees."

"The temperature is 1620 degrees and the temperature is starting to drop."

"The temperature is 1610 degrees."

Soon, the temperature dropped below the 1600-degree mark.

The oxygen content blown in now is the standard 99.5.

Su Changming asked loudly: "The temperature is already lower than the steelmaking requirements and is continuing to drop. What should I do?"

He has nothing to do.

With or without an external heat source in the converter, the only thing that can be controlled is the oxygen content.

Jiang Chen waved his hand: "Continue to blow in oxygen. When the temperature drops below 1300 degrees, stop blowing in oxygen."

The tapping temperature of steelmaking is always 1600 degrees.

Below this temperature, steelmaking is basically declared a failure.

Below 1300 degrees, the molten pig iron begins to solidify, and it is meaningless to continue to blow in oxygen.

Ten minutes later, the temperature in the furnace was already below 1300 degrees, and Su Changming stopped supplying oxygen.

Because the temperature is so low, there is no need to add coolant for cooling.

He directly directed the workers to remove the molten steel from the converter and wait for deoxidation and cooling before inspection.

The entire smelting process lasts about 15 minutes, and the temperature is above 1600 degrees for less than three minutes.

As an old worker in a steel mill, everyone knows that this experiment was a failure, and the expressions on their faces are not very good.

Jiang Chen stepped forward and said with a smile: "Why are you frustrated? Failure is success. Mom, I failed this time. Just make adjustments and try again next time."

"And through this experiment, the temperature can reach over 1600 degrees, which shows that this method can make steel. This is a useful result."

"Let's go, find a place to discuss?"

A few people came to a place not far from the converter, pulled up a chair, sat down, and began to sum up their experiences.

Su Changming said: "The biggest problem in this experiment is that the temperature rise is too slow and the high temperature duration is too short."

He knew what the problem was, but he didn't know why it happened or how it needed to be improved.

Lu Yuehua said: "So, our assessment of the oxygen content is insufficient. According to this situation, high-purity oxygen should be used from the beginning."

Jiang Chen nodded: "Well, I think the injection of more than 99% oxygen is okay."

"But the duration of high temperature is short. If we use high purity from the beginning, the heating rate may be increased, but because the reaction is more violent, the duration will be shorter."

Lu Yuehua said: "Well, that should be the case. This short duration, I think the biggest reason may be the lack of reactants."

"After carbon, silicon and other substances are consumed, there is no substance that can continuously provide heat for a hundred years, resulting in insufficient reaction time."

Jiang Chen asked: "So how does Teacher Lu think this problem should be solved?"

Lu Yuehua thought for a while and said: "Increase reactive substances, such as adding carbon or silicon to the furnace charge, so that it can provide heat for a longer period of time."

Jiang Chen nodded: "Well, Teacher Lu will calculate it later and see how much this increase is appropriate."

"But for the next experiment, let's increase the oxygen content from 80%."

Directly adding reactants to the furnace charge may cause the reaction to become more violent. To be on the safe side, Jiang Chen adjusted the initial oxygen content.