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 Aerospace Power 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 kind of thing the French made themselves...
We don’t know yet.
So, 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. Only the outer contour parameters are slightly different.
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 all 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 began to verify the process parameters of drilling according to the production requirements provided by China.
However, we 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.
Afterwards, as the samples provided by the Chinese arrived, Vesta focused on the most urgent testing tasks.
It is not until now that all other work has come to an end that we can start to focus on production-level issues again.
“Doctor, this is the blade sample we made using different processing methods and processing techniques in the past month.”
Gene Duflo, the head of trial production, said to Vista He was led to a workbench, pointed at the dozens of turbine blade samples densely spread out on the workbench, 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 did not reply immediately, but just nodded, which was considered to be recognition of the other party's choice.
As long as the holes in 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 still some samples that cannot even be successfully punched, so they are not placed here."
" Generally speaking, if production efficiency is not considered, we can produce products that meet the requirements. Of course, 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 of leaves and handed it to Vesta.
It is of course impossible to tell with the naked eye whether the inner wall of the air film hole meets 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 root of the blade, the words "EHB-29" were written.
“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 etching marks left after the tube electrode was processed around the air film holes -
This kind of mark only remained on the heat insulation The coating surface will not affect the base material, and the temperature around the air film holes is relatively low, so the requirements for heat 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 tunnel is too complex and the depth of the hole is relatively large. There is no way to avoid electrodes. Secondary corrosion caused by the gap surface on the opposite side.”
“Furthermore, the sodium nitrate solution will precipitate insoluble salts during the electrolysis process. In the past, when we processed fan-shaped through holes, it was easy for salt crystallization to precipitate. However, because the internal structure of this channel is too complex, there is a probability of more than 90% that the processing channel will be blocked during the processing. If the blockage is not processed in time, discharge breakdown will occur. Not only will the workpiece be scrapped, but even the electrode may be damaged. Change it together..."
"So later, 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, it will not There may be a clogging problem, so after debugging the parameters for about half a month, we finally got the first sample that fully meets the standards."
He pointed to the EHB29 in Vesta's hand.
"You just said...if you don't consider production efficiency..."
Vista looked at the blade in his hand and slowly said: "You mean the electro-hydraulic beam processing process is very cumbersome?"
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"Yes..."
Duflo sighed, and then replied:
"Theoretically speaking, electro-hydraulic beam machining is good at processing tiny holes with special angles. 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, so processing The time has doubled.”
“The sample in your hand, not including the process preparation stage, took almost a day and a half to produce... Calculated this way, it takes us about 45 days. It takes about 100% to complete the processing of all the components required for an engine..."
Hearing this answer, Vesta couldn't help but curled his lips.
Although the demand for military engines is not high, building 9 units a year is too abstract.
Even taking into account the proficiency issue, the mass production speed will be doubled.
18 units a year is still not enough.
Not to mention the civilian models derived from it later.
You know, when they first came to Huaxia, they originally just wanted someone to help solve the reliability problem of the M88-2.
As a result, it became a slippery slope to help with performance upgrades throughout the life cycle.
More recently, when it came to the SeA series of products, even half of the development leadership was taken away by the other party.
If mass production in the future has to rely on others to complete key processes...
"Hiss..."
Vista couldn't help but take a breath of air.
He never had time to think about it before.
The result is now that I think about it.
It seems...not completely unacceptable?
Thinking of this, Vesta quickly shook his head, trying to drive away the random thoughts in his mind. At the same time, he warned himself that this must be affected by the sausage-slicing tactic.
In order to divert attention, he quickly asked a new question:
“Have you studied the samples provided by Huaxia, and can you refer to their hole-making methods? "
In the past, Vesta would never have said such a thing.
But now, even he himself has begun to refer to Chinese technology to upgrade the M53-P2, so it doesn't matter.
“Of course, after I heard the test results came out a few days ago, we asked for a few brand new blades for backup.”
As he spoke, Duflo He turned around and came to a computer and opened a Word document placed on the desktop.
Vista also moved closer to the screen.
“Judging from the conditions of the inner holes, we can indeed find some significant processing features, but when combined together... it is difficult to determine what kind of process it is.”
Duflo said in a distressed tone while rolling the wheel to turn the page:
"Through a high-performance microscope, the remelted layer can be vaguely distinguished from the inner wall of the air film hole. Although the thickness is very small, it will not be There is no impact on performance, but the traces will definitely be left by thermal processing. In addition, Huaxia’s technical staff 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 micro-cracks, even those that only exist on the surface of the coating, and it does not look like a product of pure laser processing...”
“You I have read the paper you mentioned."
Vista suddenly interrupted:
"Not only China, the British are actually also studying related technologies 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, It 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 aviation, in addition to the core technology level, everyone Overall it is relatively open.
Therefore, although Snecma cannot participate in the competition of this ultra-thrust level aviation engine, you can still get relevant information in time as long as you are willing.
However, Duflo is only a mid-level technician and is not very interested in things that he cannot participate in, so he continues the original topic:
"So... the direction we are currently considering is whether the Chinese will use composite processing technology, such as using electrolyte jets to assist laser processing. This can at least explain why they can control thermal stress and remelted 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.”
Tu Qiongdagger saw that it was yes.
It is naturally impossible to develop new technologies without money.
Of course Vista also understands this, but the group’s current funds are indeed somewhat tight.
"How feasible do you think it is?"
After hesitating for a moment, he still opened his mouth to confirm.
“If the simple electro-hydraulic beam process can be successful, then the efficiency of composite processing will not be lower at least.”
Duflo’s first sentence was very simple, but then The conversation changed:
“As for whether we can reach the level of the Chinese... I can’t make a conclusion yet...”
(End of this chapter)