526 molten steel rushing

Putting aside Yang Wenjun's secret calculation of Jin Xuanxun, let's turn our attention back to the Hanhua Heavy Factory area in Xunyang.

In the spacious foundry workshop, four huge ladles have been hoisted into place by the casting crane, waiting for the order to open the ladle and pour. In these four ladles, there are more than 500 tons of red-hot molten steel, which workers will use to cast the first beam of the 15,000-ton hydraulic press.

"Master Li, whether you succeed or not, it's up to you." Lin Zhenhua stood beside the old stylist Li Genyuan and said to him with a smile.

The people in the entire workshop are all in place, nervously preparing for the arrival of the last moment, and the only two idlers are Lin Zhenhua and Li Genyuan. Lin Zhenhua, as the chairman of the group, naturally does not need to operate it personally. Li Genyuan is the honorary commander of casting modeling appointed by Lin Zhenhua, and he has been busy for more than a month with dozens of modeling workers, and now he can finally take a break. The casting process was very intense, and with Lee Geun-won's age, he couldn't adapt to such a rhythm, so he had to step aside and be an audience.

"Mr. Lin, I am sweating in the palms of my hands now, I have never made such a large casting." Li Genyuan said.

Lin Zhenhua said: "Master Li, don't worry, Liu Gong, Zhang Gong, and Xiao Zhen, haven't they all been counted many times, there will be no problem." ”

Li Genyuan smiled embarrassedly: "Alas, when people are old, they are less courageous." Speaking of which, this pouring plan, didn't you also ask Mr. Lin to review it, it must be fine. ”

"Uh...... I'm not particularly good at this. Lin Zhenhua began to pretend to be modest.

Speaking of which, the casting process of this casting that is about to start is indeed a brain-racking process. Because of the production of chemical equipment, Hanhua Heavy Industry often has to manufacture some large castings, but the largest castings cast in the past are only more than 100 tons. This time, they made the upper beam of the 15,000-ton hydraulic press, and according to Zhang Yuquan's suggestion, the entire beam adopts an integrated design, which means that a component weighing more than 300 tons will be directly cast at one time.

The benefits of the integrated design of the beam are very obvious, because there is no need to use welding or nut sturding and other connection methods, the structure of the beam will be more stable, and it can withstand the repeated impact of 15,000 tons of forging pressure. However, the challenge posed by this design was also very serious, that is, GCA Heavy Industries had to overcome the casting process problem of ultra-large castings.

The casting process is very simple, probably first make a wooden mold that is exactly the same as the casting, and then bury the wooden mold with special molding sand to fill every gap. This kind of molding sand should be able to withstand the high temperature of thousands of degrees to the molten steel, and it must also have sufficient strength to not deform under the impact of the molten steel. After the molding sand is filled, the modeler has to remove the wooden mold, leaving a modeling cavity. When casting, the molten steel is directly injected into the cavity, and after cooling and solidifying, the molding sand is removed and the casting is made.

For small castings, this process is not too difficult, but as the number of castings increases, many problems that were not obstacles become obstacles become apparent.

First of all, there is the problem of the so-called "drifting core", the casting is not a complete piece of iron, but there are various cavities in the middle, which must be filled with sand mold before casting. At the time of casting, molten steel is poured into the sand mold, completely submerging the sand cores that are in the center of the casting. Since the specific gravity of the molding sand is much smaller than the specific gravity of the molten steel, under the submergence of the molten steel, these molding sand will produce a huge buoyancy and may float on the surface of the molten steel from its original position. Once this phenomenon occurs, the entire casting process is considered a failure. …,

In order to solve this problem, the stylists of Hanhua have come up with countless ways to connect the individual sand cores with steel bars, and even reinforce them with steel plates to transfer the buoyancy of the molten steel. Zhang Yuquan, Liu Zhaohua, Donnie Yen and a group of technicians took the computer and calculated it over and over again to ensure that there would be no core drifting in the pouring.

After overcoming this obstacle, another bigger problem arose, and that was the venting of the sand mold during the casting process.

Casting is a kind of high-temperature operation, the temperature of molten steel is as high as more than 1500 degrees, under such high temperatures, the molding material will undergo physical and chemical changes, resulting in a large amount of gas. If these gases are not discharged in time and remain in the cavity, they will form a huge pressure and induce an explosion.

The exhaust of small castings is very easy, it is enough to open a few exhaust ports directly on the sand mold, but this kind of large castings weighing hundreds of tons, with a few meters to more than ten meters in length, width and height, the scale of the gas formed is huge, and the traditional exhaust method is difficult to ensure that all the gas is discharged in a very short time.

In order to design this exhaust system, several engineers of Hanhua tossed for a month or two, but they could not come up with a reliable plan. Therefore, Lin Zhenhua called on everyone to work together and invited Li Genyuan, an old stylist who has been retired for many years, from Hunbei to participate in tackling key problems. In the end, it was really a plan proposed by Li Genyuan that made everyone applaud, that is, to break the previous practice of only opening the exhaust port above the sand mold, and adopt the scheme of upper and lower exhaust.

This plan, once it is broken, seems very ordinary. The difficulty of venting large castings is mainly due to the large volume, but if the upper and lower exhausts at the same time, it is equivalent to halving the distance of exhausting, and the difficulty is naturally greatly reduced. It's actually pretty easy to vent underneath, as long as you dig some exhaust grooves in the ground.

There is also a small episode here, that is, after hearing Li Genyuan put forward this two-way exhaust plan, Donnie Yen was depressed for a week. He found himself a returnee from the United States in vain, and on this kind of issue, he was not as rich as the imagination of an old worker.

In fact, it is no wonder that the more knowledgeable a person is, the more imprisoned he often has in his mind, and the easier it is to think about problems from some rules and regulations. However, some veteran workers who have worked their way up in practice are very accustomed to taking the sword off the beaten track and using some unconventional methods to solve problems.

Donnie Yen now understands more deeply what Lin Zhenhua once said to him to learn from the experience of the workers. What he learned from this psychological setback is enough to last a lifetime.

The idea of two-way exhaust is easy to propose, but how to arrange the exhaust pipes of these two circuits and determine whether the two-way exhaust can finally solve the exhaust problem still requires engineers to use scientific methods to calculate. Donnie Yen gave full play to his returnee expertise, directly built a large-scale model on the computer, and mathematically simulated the gas production, gas production rate, emission rate and so on of the sand mold, and finally concluded that this plan was foolproof.

At that time, because the application of computers was not widespread enough, large-scale mathematical simulation was still a relatively new science, and Liu Zhaohua and others were not proficient in it. However, Lin Zhenhua, as a time-traveler from later generations, is very familiar with this technology. He reviewed the entire simulation program made by Donnie Yen, and personally re-ran it several times on the machine before he was relieved. The fact that he was able to stand at the casting site and chat with Lee Geun-won so easily at this time also stemmed from his confidence in the entire calculation process.

"Get in place, let's go!"

With an order, the oxygen burning tube was accurately aligned with the eight bags on the four ladles, a string of dazzling sparks flashed, the eyes of the ladle were opened, and the molten steel poured down the holes and injected into the sand box. The sand mold spewed out blue flames several meters high at the high temperature, and all the exhaust holes made a whistle-like chirp almost at the same moment, and streams of white vapor gushed out, enveloping the entire workshop. ..., Zhang Yuquan, Liu Zhaohua, Donnie Yen and others all stood in the command position and nervously observed the entire casting process. Donnie Yen held a laptop in his hand, looked at the data on it, and said something in his mouth. Zhang Yuquan stared intently at the surroundings of the box, as if estimating the exhaust volume with the naked eye, ready to issue an order to adjust the pouring speed at any time.

It was only 7 minutes, and everyone felt like a century had passed.

"Beep!" A whistle sounded to announce the completion of the entire pouring process, and after a brief moment of stunnedness, the people in the workshop rejoiced:

"It worked!"

"Victory!"

The younger workers waved their fists, and the older workers shook hands with their colleagues, and the hearts of all the people who had been hanging for many days finally let go.

"Master Li, practice has shown that the upper and lower exhaust systems you designed are completely effective." Lin Zhenhua said to Li Genyuan, "You see, the lower exhaust system emits more gas than the upper exhaust system." ”

"It's all thanks to Mr. Lin who dares to make up his mind, I, an ordinary worker, how dare I take this responsibility." Li Genyuan was so happy that his beard trembled and replied to Lin Zhenhua.

Lin Zhenhua said: "This is still a good saying, there is an old man in the family, if there is a treasure." We cast the beam of the hydraulic press this time, from the design of the exhaust system, to the sand collision and shaping, thanks to your guidance Master Li. You old workers are the most precious treasure of our country. ”

Li Genyuan smiled: "Haha, Mr. Lin has won the award." My old man has been doing modeling all his life, and he is dying, and being able to cast such a large piece of more than 300 tons is worth it in this life. ”

Lin Zhenhua said: "Master Li is too pessimistic, we will still have big castings in the future." Our 15,000-ton hydraulic press is prepared for the forging of those large workpieces, and when the time comes, you are ready to show your skills. ”

"With Mr. Lin's words, my old man will be young again. Mr. Lin, it's really nice to follow you to do things! ”

"Master Li, it's not my credit, it's that you've caught up with a good time. If China's industry wants to go global, we have the opportunity to do business happily. ”

*J