Chapter 278 Help Mr. Xiang to make things perfect

The next day, the 17th Ministry of Machine Building and its subordinate Third Steel Rolling Mill and Beijing Iron and Steel Plant received a notice from the Ministry of Chemical Industry, inviting them to attend the Ministry of Chemical Industry's seminar on the formal promotion and construction of an industrial urea plant that afternoon.

The reason for inviting them is very simple. Urea steel is all provided by the 17th Ministry of Machine Building, and the Third Steel Rolling Mill and Beijing Steel Plant are the pioneering units of urea steel. It is also necessary to invite them to participate in this demonstration meeting. After all, they are more familiar with the material properties.

After receiving the notice, Gao Zhendong put it aside for the time being. He is now busy discussing the matter of the new thermocouple with Liang Faming and Liu Rongguo.

The new thermocouple selected by Gao Zhendong is a Type B thermocouple. The outstanding features of this type of thermocouple are wide temperature range, long life, and high upper limit. Moreover, among all thermocouple graduations, Type B has the highest accuracy and best stability, and does not require temperature compensation wires.

Of course, this thing is not without shortcomings. It has a small thermoelectric potential, low sensitivity, poor mechanical strength at high temperatures, is afraid of pollution, and is not suitable for reducing atmospheres or atmospheres containing metal or non-metal vapors. Therefore, the protective tube of this thing is relatively special. But Gao Zhendong happened to have the technology to solve this problem.

Gao Zhendong didn't make this thing at first. One reason was that the technology at hand at that time could not support the production of this thing. The second reason was very simple and direct: it was expensive!

This thing is extremely expensive. Compared with the K-type thermocouple that can work at 1300℃ and does not use any precious metals, the B-type thermocouple can work at 1600℃ and 1800℃ for a short period of time, but it is of no use in most application environments.

On the contrary, it is its material that determines that it cannot be widely used. Its electrodes are platinum-rhodium 30-platinum-rhodium 6, that is, the positive electrode (BP) is 70% platinum and 30% rhodium, and the negative electrode (BN) is 94% platinum and 6% rhodium, so it is also called double platinum-rhodium thermocouple.

The price of this thing is much higher than that of K-type material.

But in high temperature environment, this thing works well.

Gao Zhendong told Liang Faming and Liu Rongguo about the electrode ratio of type B thermocouple. They were both secretly shocked. This thing was too expensive. No wonder Director Gao was reluctant to do it at the beginning. It was because it was difficult to popularize.

When they heard about the weaknesses of type B thermocouples, they were puzzled.

Liang Faming first brought it up: "Director Gao, since this thing is not suitable for reducing atmospheres or atmospheres containing metal or non-metallic vapors, what should be used as a protective tube?"

Gao Zhendong smiled and said, "Then we will use natural treasures that are neither gold, jade, wood, nor iron to protect it."

Gao Zhendong casually made up a clever remark, which came from a common adjective in the immortal cultivation novels of his previous life. Liang and Liu were completely dumbfounded. They really couldn't understand it.

Seeing the two people's confused looks, Gao Zhendong smiled and said, "Just kidding, we use corundum."

The melting point of corundum is as high as over 2000℃, which just covers the working temperature range of type B thermocouple. Moreover, no metal or non-metal vapor will be produced at this temperature, which just meets the requirements of type B thermocouple.

But after using this thing, the price will be even higher.

"Corundum?"

The two were familiar with steel, but they were not as familiar with other things as Gao Zhendong, and they didn't even know what these were.

Gao Zhendong smiled and said, "Yes, corundum, which is aluminum oxide (Al2O3)."

The two thought about it and decided that this thing really was what it was. It just met the requirements of a Type B thermocouple, with a high melting point and high hardness. However, it was difficult to process because it was expensive.

Putting aside the issue of processing, anything that can be called "corundum" is crystal-grade aluminum oxide.

Liu Rongguo asked: "How can we obtain corundum crystals that meet the requirements?"

Gao Zhendong pointed in the direction of the single crystal furnace laboratory: "You forgot, I have a single crystal furnace, just pull a little bit."

The two men then realized that although the volume of corundum crystals could not be made large, it was just right to meet the needs of type B thermocouples.

Both of them admired Gao Zhendong in their hearts. He did things in a way that was linked together, and the results of the previous project could be used in the next project.

In fact, this is really an over-imagination. When Gao Zhendong was researching the single crystal furnace, he didn't think about the problem of type B thermocouple at all. After all, making this thing was a spur-of-the-moment idea, and the result was a slap in the face of his "studious" comrades.

Gao Zhendong then reminded him of one more thing: "Please pay attention to the fact that the diameter of the even wire is 0.5mm, and the allowable deviation is -0.015mm."

Although this requirement was difficult for Liang Faming and Liu Rongguo, it was not difficult for the Third Steel Rolling Mill, especially when it was only for small-batch production. Liang Faming and Liu Rongguo got a full set of designs from Gao Zhendong and excitedly prepared to make the B-type thermocouple. Although the report of the technical transformation plant had not yet been submitted to Gao Zhendong for review, it was always right to do things first.

When they left, they also left one thing behind: the test report of two tungsten copper materials.

The test results show that the tungsten copper material fully meets Gao Zhendong's design intentions.

Considering that there were quite a lot of things submitted to the 17th Ministry of Machine Building recently, in order to let the ministry digest them first, Gao Zhendong temporarily put the inspection reports of the two tungsten copper materials into the safe.

Gao Zhendong also put together a batch of throat liners that had already been made, and when he was free in a few days, he would send them to the Research Institute and ask them to test their high-temperature performance.
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That afternoon, when Gao Zhendong rushed to the meeting room of the Department of Applied Chemistry, he found several acquaintances already there.

The leader of the 17th Ministry of Machine Building attended the meeting in person, not because he was too idle and attended all meetings, but because the food issue has always been the top priority, and as a ministry responsible for material production, it was natural for him to be there in person. Many things would be difficult for others to make the final decision if it wasn't him.

The other person was a coincidence. He was the former secretary of the leader and was now transferred to Jingcheng Steel Plant. As the person in charge of the AOD workshop, it was normal for him to be present. It had nothing to do with production. The 17th Ministry of Machinery could make the final decision on production. He came here with the same identity as Gao Zhendong, representing another research unit of urea steel.

A few people greeted each other and sat together. As researchers of urea steel, Gao Zhendong and Zheng Liangshu were fortunate enough to sit in the first row, which was just right.

Other participants included experts from the Ministry of Applied Chemistry, people from the Agriculture Department, and people from the Ministry of Foreign Trade, because this meeting involved the question of how much urea steel they could sell abroad. Once it is determined to be promoted, it must first meet domestic demand.

The meeting actually focused on two points: one was whether the accelerated aging method used by President Xiang could reliably evaluate the service life of the production line in the actual production environment; the other was whether the output of urea steel could meet the demand once it was rolled out.

In fact, the first problem is the most troublesome. The life assessment of the urea production line is very troublesome.

The main concern of the urea production line is the corrosion life problem. Coincidentally, there is no good way to measure the corrosion life in the rapid evaluation of equipment accelerated testing.

In Gao Zhendong's previous life, even things like temperature, stress, and vibration had various accelerated test methods in the relevant standards, but there were relevant test methods for corrosion in chemical testing. However, accelerated corrosion test methods for production equipment were relatively scarce.

Basically, all corrosion prediction methods are based on a large amount of historical data and real-time monitoring, but in the case of urea steel, this condition is obviously not met.

Even in the accelerated testing and evaluation of military equipment, when the corrosion life issue is mentioned, it is only generally stated that "the relevant theory is weak and can be estimated using similar analogy."

The similar analogy method can only be used to estimate the corrosion life of the product when there is corrosion monitoring information of similar or similar products.
But the problem is that this is a new material and there is no historical data available, so the similarity analogy method is useless. Moreover, the monitoring methods available today can hardly provide corrosion monitoring information.

Therefore, the corrosive soil method proposed by President Xiang and his team to accelerate the test results did not completely dispel the doubts of the participants. No one had any idea how long this thing could last in a production environment.

Regarding this question, there is no doubt that apart from Mr. Xiang and others, the most authoritative or most suitable person to answer this question is definitely Gao Zhendong.

Although Zheng Liangshu represents another research direction, his knowledge structure is obviously not suitable for answering this question.

The leader of the Department of Applied Chemistry personally pointed out: "Director Gao, as a researcher of urea steel and an expert in materials, we would like to ask you to evaluate whether the accelerated corrosion aging method used by Xiang Gong is appropriate?"

Seeing that everyone was looking at him, Gao Zhendong was thinking in his head how he could help President Xiang and the others to rationalize this matter.

Gao Zhendong fully believes in the corrosion resistance of this material and its applicability in the urea industrial production line. His confidence has nothing to do with Mr. Xiang and others, but lies in the source of this material.

It is stated very clearly in the paper on the source of the materials that the working time was far more than one year by the time the paper was published, and everything was normal within the design life.

Therefore, what Gao Zhendong needed to solve was how to justify the experimental results of Mr. Xiang and others.

Fortunately, as a student majoring in automation, he happened to know a reasonable method, which he learned in his previous life. The current automation major does not teach that method because it has not been developed in this year.

Even Gao Zhendong received special lessons from his instructor; his classmates had never taken this course because it was not actually a course in the automation field.

However, the only thing that made Gao Zhendong unhappy was that this method involved partial differential equations, and he had to explain the principle clearly to people, so in the distance process, it was inevitable to solve two partial differential equations.

This method is the grey system theory model, a very abstract cybernetics method. Even in Gao Zhendong's previous life, it was considered a new method in the field of cybernetics.

(End of this chapter)