Following the direction pointed out by Chang Haonan, Zhong Shihong quickly saw the leaves stacked in the corner:

"Oh, most of them are waste products that have been damaged or failed to pass the test, and have been judged to be unusable."

"Scrap?"

Chang Haonan was stunned:

"So many?"

Although it was far away, he could still see that there were at least hundreds of leaves there.

For a factory with full production capacity, this quantity may not be nothing, but in recent years, the army's order volume has been insufficient, and it has to be distributed to Zhucheng and Shengjing for production, so a large part of the production capacity of Factory 410 is idle.

After such a calculation, the yield rate does not seem to be optimistic.

Is it not difficult to produce good compressor blades?

"Hmm...... In fact, it's not much, these are the amounts accumulated in the last half a year, and they also include turbojet 13 and turbojet 7, which are all piled up there. ”

Zhong Shihong explained while directly bringing Chang Haonan over, and then picked up a leaf from the ground:

"Originally, these things should be disposed of regularly, but we have an engineer who has recently been working on repairing these damaged scraps with hardfacing technology, so we left some of them for him."

"And that's just part of it?"

The latter was a little dumbfounded by the rather spectacular scene in front of him, and only after a while did he ask:

"So what is our overall yield rate?"

"Is this...... The pass rate of a three-coordinate test is about 60%, but the remaining 40% can still be saved, and it can reach about 80% overall, and it can reach 85% in good times. ”

As the head of the technology department, Zhong Shihong naturally treasured these data, and reported the answer almost without thinking, and at the same time handed the blade he had just picked up to Chang Haonan.

"So high? What about these ......"

The latter turned over and looked at the scrap in his hand, but it was really difficult to see what was wrong with the naked eye.

"The yield rate is only based on the processing process." Zhong Shihong slightly fixed the hat he wore on his head: "Most of the blades in here are damaged during assembly and testing. ”

"At present, most of the compressor blade materials are only martensitic stainless steel, and at most low-grade ordinary titanium materials such as Ti-6Al-4V are used.

"But you know, China's aero engines borrow a lot from Soviet design, so some riveted structures will be used in the assembly process of blades and wheels and casings, and the materials of these aviation fasteners are generally the Soviet Union's БТ16 titanium alloy, that is, Ti-3Al-5Mo-4.5V, which is still a new thing for us, whether it is production, processing or assembly, it is relatively easy to have problems."

"I see," Chang Haonan knew ......in his heart, and secretly wrote down what Zhong Shihong said.

Huaxia's research on titanium alloy materials itself is not too late, such as TB2, TC4, these large quantities of titanium alloys in the aviation field, are basically completed in the 60-70s of the localization.

Including the БТ16 mentioned by Zhong Shihong just now, its localized model TC16 titanium alloy was also born around 1990.

But the problem is that just having a piece of material is useless.

The production of titanium alloy bars is only the first step in a long journey.

And taking a step back, even the latest brands of products such as Ti1100 in the United States and БТ36 in Russia are not restricted from exporting, as long as they are willing to spend money, it is not difficult for most countries (such as India) to buy.

However, each different material, due to its different physical and chemical properties, requires corresponding treatment and processing technology before it can really be turned into a usable product.

These processes are almost impossible to obtain by imitation, and they are also the part that really forms a technical barrier.

Obviously, the 410 factory was stuck in these two links.

Subsequently, Chang Haonan visited several other processes under the leadership of Zhong Shihong, but he always thought about the pile of waste just now.

Finally, when he saw the riveting assembly process mentioned earlier, he couldn't help but ask:

"Speaking of which, since our compressor is already a new design, can't we consider giving up the riveting structure and completely replacing it with tenon joints? Moreover, the formation of a transitional fit or a small gap fit between the tenon and the tenon groove can also reduce the vibration of the compressor when working, and the service life is also higher. ”

Although Chang Haonan is also the first time to watch the production process of aero engines, he has the knowledge and experience of later generations very well, even in the Soviet-made engine, the use of rivets as the connection of blade fasteners is absolutely a strange skill, but in the R11F-300 engine introduced with the J-7, this is exactly the one used.

This question really made Zhong Shihong a little impressed with Chang Haonan.

At least it shows that the latter is not just coming to the factory to put a score, but really has a certain understanding of production and processing.

"Of course, we have also considered riveting and changing tenons, but the processing of dovetail-shaped tenons is very difficult, and the pressure surface tenon as an assembly benchmark needs to be broached, and special combination broaches are required.

Obviously, when God closes a door, he often seals the window as well.

Therefore, for the Huaxia Army workers who are groping their way forward in the ups and downs, if they want to find a way out, they have to find a way to lift the roof.

"Forbidden ......"

Chang Haonan raised his head again and looked around, and indeed found that most of the processing equipment here was imported from Germany or Japan.

Although the famous Paris Coordinating Committee was dissolved in 1994, its list of embargoed items was inherited almost intact by the Wassenaar Agreement, and the embargo pressure on China has not diminished.

You must know that in the list of embargoes in Batumi, there are even nearly 600 items listed separately for China than for the Soviet Union before the disintegration.

For example, high-precision multi-axis linkage machine tools can be exported to the Soviet Union, but not exported to China.

"Yes, in areas such as machining, there is indeed a big gap between us and developed countries." Zhong Shihong's tone was full of helplessness:

"We have also tried to use domestic tools for import substitution, but neither the machining accuracy nor the service life can meet the requirements, and can only be used to process some things with low precision requirements."

Speaking of this, he turned his head to look at Chang Haonan next to him, and said half-jokingly: "During this time, I sometimes think that if there is a talent like you in our industry, it would be great." ”

"What ...... this?"

Chang Haonan wants to say that it may not be impossible.

After all, according to the current progress, the development of turbofan 10 will have to be officially put on the agenda next year at the earliest.

By that time, there must be a lot of manufacturing problems that he needs to solve.

But after thinking about it, I still didn't say it.

On the one hand, he doesn't know much about this field.

On the other hand, the efficiency of the transformation of achievements in the field of machining is also relatively low.

Therefore, even with the help of the system, it is difficult to make a breakthrough in a short period of time like fluid dynamics simulation.

Since this is the case, it is better to let Zhong Shihong emo for a while-

As long as I didn't expect it, everything was a surprise.

"In addition to the problem of the fastening method of the blade, are there any other difficulties in the manufacturing process of our factory?"

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, it is full of difficulties, it is difficult to pass the pass, and it is difficult to walk step by step." Zhong Shihong smiled bitterly and shook his head:

"But it must be said, the next is the manufacture and testing of the aviation casing, because it is a large integral thin-walled part, so it is very difficult to cast, and the current use of no margin investment casting method, the yield and production efficiency are not ideal."

"There is also a turbine blade, because it is a hot-end component, so the material requirements are much higher than that of the compressor, such as the turbojet 14 turbine blade also has an air film hole for active cooling, which is also a headache to process."

"The third is ......"

Listening to Zhong Shihong's inventory one after another, Chang Haonan felt that his head was a little bigger......

I went to my parents' side for dinner tonight, and I added one chapter first, and the rest of the days will be made up one after another (the monthly ticket money lord voted 83 votes, so add 8 chapters)

(End of chapter)