Chapter 103 Creating Difficulties (Additional update 18 for monthly ticket financier flankerr)
Following the direction pointed by Chang Haonan, Zhong Shihong quickly saw the blades stacked in the corner:
" Oh, those are basically waste products that have been damaged or failed to pass the test and are judged to be unusable.”
“Waste products?”
Chang Haonan was stunned:
"Are there so many?"
Although it was far away, he could still vaguely see clearly that there were at least hundreds of leaves there.
For a factory with full production capacity, this quantity may not be a big deal, but in recent years the army's order quantity has been insufficient, and production has to be divided between Zhucheng and Shengjing, so the 410 factory has A large portion of production capacity is idle.
After such calculation, the yield rate does not seem to be optimistic.
Is it said that the production of compressor blades is not difficult?
"Well...it's actually not much. These are the amounts accumulated in the past six months, and they also include Turbojet 13 and Turbojet 7. They are all piled up there."
Zhong Shihong explained as he directly put Chang Haonan He took it over and then picked up a blade from the ground:
“Originally, these things should be disposed of regularly, but we have an engineer who is currently studying the use of surfacing technology to repair these damaged scraps. So I left a part of it for him.”
“Are these just part of it?”
The latter looked a little dumbfounded at the spectacular sight in front of him, and then asked after a while:< br>
"Then what is our overall yield rate?"
"Well...the passing rate of three-dimensional coordinate inspection is about 60%, but the remaining 40% can still be saved. Overall It can probably reach about 80%, and when it is good, it can reach 85%. "
As the director of the technology department, Zhong Shihong is naturally familiar with these data, and reported the answer almost without thinking, while casually picking up the data. The leaf was handed to Chang Haonan.
"So high? Then these..."
The latter turned it over and looked at the waste product in his hand, but it was really difficult to see what was wrong with the naked eye.
"The yield rate only considers the processing process." Zhong Shihong fixed the hat on his head: "Most of the blades here are damaged during the assembly and testing process."
"At present, most of the blades are damaged during assembly and testing." Most compressor blades are made of martensitic stainless steel, and at most low-grade ordinary titanium materials such as Ti-6Al-4V are used. We are familiar with the milling of these materials, and at most add a few stress relief processes. It just affects some production efficiency.”
“But you know, our country’s aero engines borrow a lot from Soviet designs, so some riveting structures are used in the assembly process of blades, discs and casings. These aviation tight structures The material of the firmware is generally Soviet-grade БТ16 titanium alloy, that is, Ti-3Al-5Mo-4.5V. It is still a new thing for us, and it is relatively easy to have problems whether it is production, processing or assembly. "< br>
"So that's it..." Chang Haonan understood in his heart, and secretly wrote down what Zhong Shihong said.
China’s research on titanium alloy materials itself is not too late. Titanium alloys such as TB2 and TC4, which are used in large quantities in the aviation field, were basically domestically produced in the 1960s and 1970s.
Including the БТ16 just mentioned by Zhong Shihong, its domestic model TC16 titanium alloy was also born around 1990.
But the problem is that just a piece of material is useless.
Producing titanium alloy rods is only the first step in a long journey of thousands of miles.
And to take a step back, even for the latest brands of products such as the United States' Ti1100 and Russia's B36, the blanks themselves do not restrict exports. As long as they are willing to spend money, it is not difficult for most countries (such as India) to Buy it.
However, each different material, due to its differences in physical and chemical properties, requires corresponding treatment and processing technology before it can truly become a usable product.
These processes are almost impossible to obtain through imitation, and they are also the real technical barriers.
Obviously, Factory 410 is stuck in these two links.
Subsequently, Chang Haonan visited several other processes under the leadership of Zhong Shihong, but he was always thinking about the pile of waste products just now.
Finally, when he saw the riveting assembly process mentioned before, he couldn't help but ask:
"Speaking of which, since our compressor is already a new design , can’t we consider abandoning the riveted structure and replacing it with mortise and tenon joints? Moreover, forming a transition fit or a small gap fit between the tenon and the tenon groove can also reduce the vibration of the compressor during operation, and the service life will be higher. ”
< br>
Although it was Chang Haonan's first time to watch the production process of an aero-engine live, he knew very well with the knowledge and experience of later generations that even in Soviet-made engines, the use of rivets as blade fasteners was definitely a gimmick. Coincidentally, this is the engine used in the R11F-300 engine introduced with the J-7.
This question really made Zhong Shihong look at Chang Haonan with admiration. At least it shows that the latter is not just coming to the factory to show off, but actually has a certain understanding of production and processing.
“Of course we have considered replacing riveting with tenon joints, but the processing of dovetail tenon is very difficult, and the pressure surface tenon as the assembly reference requires broaching, which requires special Due to the ban on sales, it is no longer possible to purchase in bulk through regular channels.”
Obviously, when God closes a door, he will also seal the window.
Therefore, for the Chinese military workers who are groping forward in the ups and downs, if they want to find a way out, they have to find a way to lift the roof.
“Sales are prohibited...”
Chang Haonan raised his head again and looked around, and indeed found that most of the processing equipment here were imported from Germany or Japan.
Although the famous Paris Coordinating Committee was disbanded in 1994, its list of prohibited items was inherited by the Wassenaar Agreement almost intact, and the embargo pressure faced by China has not diminished. Small.
You must know that in Batumi’s embargo list, there are nearly 600 more items listed for China alone than for the Soviet Union before the disintegration.
For example, high-precision multi-axis machine tools can be exported to the Soviet Union, but not to China.
"Yes, in fields such as mechanical processing, there is indeed a big gap between us and developed countries." Zhong Shihong's tone was full of helplessness:
"We are also trying They tried to use domestic tools to replace imported ones, but neither the processing accuracy nor the service life met the requirements, and they could only be used to process things that did not require high precision.”
At this point, he turned his head again. Looking at Chang Haonan next to him, he said half-jokingly: "During this period, I sometimes think, it would be great if there could be a talent like you in our industry."
"This..."
Chang Haonan wanted to say that it might not be impossible.
After all, according to the current progress, the development of turbofan 10 will have to be officially put on the agenda as early as next year or the year after next.
By that time, there must be many manufacturing problems that need him to solve.
But after thinking about it, I finally didn’t say it.
On the one hand, he doesn’t know much about this field.
On the other hand, the achievement conversion efficiency in the field of mechanical processing is also relatively low.
So even with the help of the system, it is difficult to achieve breakthroughs in a short time like fluid dynamics simulation.
In this case, it’s better to let Zhong Shihong emo for a while first——
As long as I have no expectations, everything will be a surprise.
“Apart from the problem with the blade fastening method, do our factory have any other difficulties in the manufacturing process?”
Chang Haonan's tone seemed to be just asking casually, but in fact he wanted to determine which aspect of knowledge he wanted to learn next.
"If you really want to say it, there are difficulties everywhere. It is difficult to pass every pass, and it is difficult to walk step by step." Zhong Shihong smiled bitterly and shook his head:
"But it must be If anything, the next step is the manufacturing and testing of aircraft engine casings. Because it is a large overall thin-walled part, it is very difficult to cast. The current no-margin investment casting method has unsatisfactory yield and production efficiency. . ”
“The other is the turbine blade. Because it is a hot-end component, the material requirements are much higher than that of the compressor. The turbine blades of the turbojet 14 also require active cooling. Membrane holes are also a headache to process.”
“The third one is...”
Listening to Zhong Shihong's inventory one by one, Chang Haonan felt that his head was a little big...
I went to my parents' place for dinner tonight. I will add a chapter first, and the rest will be added in the next few days ( The monthly ticket sponsor voted 83 votes, so 8 chapters are added)
(End of this chapter)