Chapter 1140

In the engine, the role of the blade is very important. Moreover, in the working process, the blade will be subjected to centrifugal force, aerodynamic force of air, thermal stress, alternating force, random load and so on. Under the action of various loads, the blade is very prone to high cycle fatigue, thermal fatigue and low cycle high stress fatigue damage.

If the blade is unqualified, it will spray parts continuously after it is on the bench, and a fragment will fly out at high speed, which is enough to cause an accident.

Such a scene, in the later Han engine development, I do not know how many times.

Now, even with the success of Spey's research and development, it can not guarantee the smooth development of a new generation of engines.

Blade materials include aluminum alloy, stainless steel, titanium alloy, superalloy and composite blade, etc. The specific material selection shall comprehensively consider the working temperature, strength, state and weight.

In contrast, economy is the last thing to consider. In the past, turbojet engines in Han Dynasty used stainless steel or aluminum alloy compressor blades, but now titanium alloy has been used.

Titanium alloy is widely used in the aviation field because of its low specific gravity, high specific strength, corrosion resistance and outstanding contribution to weight reduction. Take the current J-11 fighter for example, the use of titanium alloy on it has greatly increased.

In addition to using materials, the design shape and processing technology are also very different.

The initial fan blade is limited by manufacturing technology and is a solid, narrow string, damped boss structure. With the development of manufacturing technology, in order to improve the aerodynamic efficiency of fan blade and reduce the weight of fan, the solid structure is replaced by wide string, sandwich or hollow structure. Spey's engine blades are solid and only use the precision casting process. It is said that the core machine of the new three-generation machine should adopt the hollow titanium alloy structure. Unfortunately, because the processing technology is not qualified and due to cost considerations, Wu Lao is still using the blade processing technology on Spey.

The processing technology has not changed, but the style of the designed blade has also changed, so it naturally can not meet the requirements.

Titanium alloy has high yield strength, poor plasticity and easy rebound at room temperature. Most of the engine blades formed by conventional metal technology are difficult to ensure the dimensional accuracy, time-consuming and laborious, and can not ensure their performance well.

This calls for the arrival of new processes, and superplastic forming / diffusion welding technology is a combined processing technology developed by using the good solid-state adhesion of materials in Superplastic State.

The process can use the excellent superplasticity and diffusion connectivity of titanium alloy to manufacture titanium alloy multi-layer structural parts. The cost and weight can be saved by about 30% ~ 50%. It can save man hours, save raw materials, improve efficiency, and process various structural parts with light weight and good structural stiffness.

Superplasticity usually refers to the abnormally high elongation of materials under specific tensile conditions without necking and fracture. When the elongation is greater than 100%, it can be called superplasticity.

Diffusion bonding is a bonding method in which two or more solid materials are tightly pressed together, heated to the temperature below the melting point of the base metal in vacuum or protective atmosphere, and pressure is applied to make the micro uneven part of the connection interface produce micro plastic deformation to achieve close contact, and then form a firm metallurgical bonding through thermal insulation and atomic diffusion.

Why can Spey be exported to Han? Because Spey is the engine of the previous generation of NiuGuo people, and the thrust weight ratio is only 5. Since it has fallen behind, of course, it can export to make money.

But how could the most advanced technology just developed be given to the Han state?

"If we want to realize this latest process, we need diffusion connection - superplastic forming equipment, diffusion connection heating equipment, diffusion connection - superplastic forming vacuum equipment. As long as we have these equipment, I can operate it," Robert said.

He also knows the difficulties. It would be better if Han imported these equipment from abroad.

"At the same time, the superplastic forming temperature of titanium alloy is 850 ~ 980 ℃, and the diffusion bonding temperature is 870 ~ 1280 ℃. Because the temperature during superplastic forming meets the temperature conditions of diffusion welding, and both of them need to be carried out in vacuum or shielding gas, the two processes can be combined to complete the superplastic forming and diffusion bonding process in the process of one heating and pressurization. I thought for a long time It's a pity that the brick manufacturers of Luoluo company were afraid of producing defective products and didn't adopt them. "

This is not what CNC machine tools can do. Advanced CNC machine tools only improve the machining accuracy. The manufacturing of titanium alloy blades requires an updated process. It is not produced by turning, but directly superplastic forming and diffusion welding.

Qin Guan nodded and suddenly thought of something. It's very simple. How are the blades of f404 engine processed? Will the same process be used?

In particular, is the engine production line also responsible for producing this kind of blade?

The fighter has countless parts, and the production line is just the final assembly line, but the engine is definitely not like this. After all, the engine is a high-tech product, and maybe some accessories are purchased, but the main body of the engine must be produced on a production line. If the blades of the continuous engine are also produced by other subordinate factories, can the engine be produced?

Qin Guan thought of this, made up his mind and said, "we must adopt new technology to achieve the transcendence of this three-generation machine. Since we are required to use this blade, let's build it. As for relevant equipment, let's find a way for northern industrial company."

Old Wu was immediately delighted. Since Qin Guan said to think of a way, he must be able to think of a way. If this kind of blade can be made, the core engine of the engine will never fail in the retest.

As for now, the engine can't be tested. We must wait for the arrival of new technology.

"Mr. Qin, such engines use a lot of titanium alloy. I'm afraid the price will go up," Wu continued.

"No matter how high the price is, it's lower than we buy the engine? Moreover, in this way, we will control our fate in our own hands and won't be stuck by the engine. Mr. Wu, let's talk in detail. In addition to the most critical high thrust engine, we also have a strong demand for medium thrust engines."

Mr. Wu took off his glasses and rubbed his eyes: "yes, we still have the demand of zhongtui, Mr. Qin, but we can't be busy."