Chapter 971 Guessed It, but Not Completely

In fact, while the British felt threatened, Snecma on the other side of the English Channel was not as joyful as the former imagined -

For Dassault and Aerodynamics Group, as soon as Vesta signs off, the testing of the turbine components of the M88-3 engine can be considered over, and the next step is to enter the next phase of work step by step.

However, for Snecma himself, it was far from the case.

Don’t forget, in order not to delay the critical time node, the samples used in this round of testing were all directly provided by China.

So now the most we can confirm is that "there are no problems with the turbine components designed and produced by China."

But what do the French make themselves...

Don't know yet.

Therefore, after sending the test report to the two upstream and downstream partners, Vesta almost had no time to rest and immediately turned its attention to the trial production workshop.

The materials, coatings and production processes used in the M88-3 turbine itself have not changed at all compared to the M88-2, with only slight differences in the outer contour parameters.

But it is not difficult for established industrial countries to solve.

In fact, from beginning to end, the semi-finished blanks used by China were provided by Snecma.

Therefore, the only technical difficulty that needs to be overcome is the final manufacturing of the air film holes.

Since the end of November last year, when Vesta brought relevant technical data back to France, Snecma's production department has begun to verify the process parameters of drilling processing in accordance with the production requirements provided by China.

However, it encountered huge resistance at the beginning, resulting in almost zero progress in the first few weeks.

Not to mention good products, not even complete scraps were produced.

Later, as the samples provided by the Chinese arrived, Vesta focused on the most urgent testing tasks.

Only now that all other work has come to an end can we start to focus on production-level issues again.

"Doctor, these are the blade samples we made using different processing methods and processing techniques in the past month."

Gene Duflo, the person in charge of trial production, led Vesta to a workbench, pointed at the dozens of turbine blade samples densely spread out on the table and introduced:

“We have checked the design documents and found that although the specific hole shapes involved in different parts are different, the basic characteristics and properties are the same, so in order to speed up efficiency, we all used blades with smaller area and thickness for trial production. "

Vesta didn't reply immediately, but just nodded, which was considered to be recognition of the other party's choice.

As long as the holes on the blades are clear, the combustion chamber and the turbine disk are basically the same.

"Is this all?"

After looking down for a while, he raised his head again and asked Duflo.

"That's not true."

The latter shook his head:

"There are also some samples that couldn't even be successfully punched, so they're not here."

"In general, if production efficiency is not considered, we can produce products that meet the requirements. Of course, at present, we can only say that they meet the requirements in terms of specifications. After all, they have not been systematically tested."

While talking, Duflo took out one of the leaves from a pile and handed it to Vesta.

It was of course impossible to tell with the naked eye whether the inner wall of the air film hole met the requirements, so Vesta did not do any unnecessary things and just took a rough look at the outer surface.

He noticed that at the base of the blade, there was the word "EHB-29" written on it.

"EHB..."

The movement of Vesta's hand stagnated slightly:

"You changed the process?"

In the past, Snecma's common process for processing air film holes was tube electrode electrolytic machining, and the sample abbreviation was generally TEE-xx.

And more importantly, he could not see the annular corrosion marks left after the tube electrode processing around the air film hole——

This trace only remains on the surface of the thermal insulation coating and will not affect the base material. The area around the air film hole is already a relatively low temperature location, and the requirements for thermal insulation are relatively low.

Therefore, unless there are special requirements, an additional coating will not be added after processing.

"That's right."

Duflo nodded helplessly:

"We have tested many times using tube electrode electrolysis, but the internal shape of their channel is too complex and the hole depth is relatively large. There is no way to avoid secondary corrosion caused by the gap surface on the opposite side of the electrode."

"Furthermore, during the electrolysis process, the sodium nitrate solution will precipitate insoluble salts. In the past, we processed fan-shaped through holes, and even if there were salt crystals precipitated, they could be easily removed. However, this is also because the internal structure of this hole is too complex, and there may be some problems during the processing. There is a probability of more than 90% that the processing channel will be blocked. If the blockage is not processed in time, it will cause discharge breakdown. Not only will the workpiece be scrapped, but the electrodes will also likely have to be replaced..."

"So later on, we simply switched to the electro-hydraulic beam machining method. Because during the machining process, the electro-hydraulic flow will rush towards the workpiece at high speed, so no matter how complicated the inside of the hole is, there will be no clogging problem. In this way, about half of the debugging process was completed. parameters, we have obtained the first sample that fully meets the standards.”

He said and pointed to the EHB29 in Vesta's hand.

"You just said...if you don't consider production efficiency..."

Vesta looked at the leaves in his hands and slowly said:

"It means that the electro-hydraulic beam processing process is very cumbersome?"

"yes……"

Dufroy sighed and replied:

"In theory, electro-hydraulic beam machining is good at machining tiny holes with special angles, and the diameter of the air film holes is calculated in millimeters, which requires repeated hole expansion in multiple stages. There are many air film holes on each blade, and the processing time is doubled."

"For the sample in your hand, not counting the process preparation stage, it took almost a day and a half to produce it... So, it will take us about 45 days to complete the processing of all the components required for an engine..."

Hearing this answer, Vesta couldn't help but curl his lips.

Although the demand for military engines is not high, it is too abstract to build 9 engines a year.

Even if the proficiency problem is taken into account, the mass production speed is doubled.

18 engines a year is still not enough.

Not to mention the civilian models that will be derived later.

You know, when they first approached Huaxia, they just wanted someone to help solve the reliability problem of M88-2.

As a result, it later slipped into helping with performance upgrades during the full life cycle.

Later, when it came to the SeA series of products, even the development initiative was divided by the other party.

If mass production in the future still depends on others to complete the key processes...

"Hiss..."

Vesta couldn't help but take a breath.

He hadn't had time to think about it before.

As a result, now that he thinks about it.

It seems... not completely unacceptable?

Thinking of this, Vesta quickly shook his head, trying to get rid of the random thoughts in his mind, and warned himself that this must be affected by the sausage-cutting strategy.

In order to divert attention, he quickly asked a new question:

"Have you studied the samples provided by China? Can you refer to their hole-making method?"

If it were in the past, Vesta would never say such a thing.

But now, even he himself has begun to refer to the Chinese technology to upgrade the M53-P2, so it doesn't matter.

"Of course. After hearing the test results a few days ago, we asked for a few new blades from there as backup."

As he spoke, Dufroy turned to a computer and opened a Word document on the desktop.

Vesta also came to the screen.

"From the situation of the inner channel, some relatively obvious processing features can indeed be found, but combined together... it is difficult to determine what process it is."

Dufroy said in a distressed tone while scrolling the scroll wheel to turn the page:

"Through a high-performance microscope, the remelting layer can be vaguely distinguished from the inner wall of the air film hole. Although the thickness is very small and will not have any effect on the performance, it is definitely a trace left by thermal processing. In addition, Huaxia's technicians have previously published an influential paper in Nature, and the content is indeed related to laser processing."

"However, the entire blade has neither thermal stress nor microcracks, even if It is not only on the surface of the coating, and it does not look like a product of pure laser processing..."

"I have read the paper you mentioned."

Vestal suddenly interrupted:

"Not only China, but the British are actually also studying the technology of using high-energy laser to process turbine components, but as far as I know... the situation is not optimistic."

"Rolls-Royce's Trent900 engine is stuck in processing efficiency. It is said that the yield rate is too low, resulting in high costs. This is also the biggest advantage of the opponent GP7200..."

In the field of civil aircraft engines, except for the core technology level, everyone is generally relatively open.

Therefore, although Snecma cannot participate in the competition of this super-thrust aircraft engine, as long as it is willing, it can still obtain relevant information in a timely manner.

However, Dufroy was only a mid-level technician and was not very interested in things he could not participate in, so he continued the original topic:

"So... the direction we are currently considering is whether the Chinese have used composite processing technology, such as using electrolyte jet to assist laser processing, which can at least explain why they can control thermal stress and remelting layers."

"Of course, this is a relatively new technology for us, and we may need some additional funds to purchase new equipment and test consumables."

The truth is revealed.

It is impossible to develop new processes without money.

Vesta certainly understands this, but the group's current funds are indeed a bit tight.

"How feasible do you think it is?"

After hesitating for a moment, he still opened his mouth to confirm.

"Even the simple electro-hydraulic beam process can succeed, so the efficiency of composite processing will at least not be lower."

Dufroy's first sentence was very straightforward, but then he changed the subject:

"As for whether it can be achieved to the level of the Chinese... I can't draw a conclusion now..."