In the rocket manufacturing factory, Natasha and Adam Cohen also saw the huge fuel tank in the rocket fuel tank workshop, which was erected and fixed on a huge test platform.

Dozens of hydraulic cylinders push and pull the fuel tank to withstand the same pressure and load as it does during lift-off and flight, simulating various vibrations and extrusions on the fuel tank during rocket launch.

The main material of the fuel tank is a special aluminum alloy, but the outside is still glued with three layers of thermal insulation technology, and the whole has an orange-yellow luster.

"Daddy, what's that?"

Amanda, the daughter riding on Yang Jie's neck, asked at this time, pointing to the huge fuel tank on the experimental table.

"Baby, that's the rocket's fuel tank. ”

Yang Jie replied with a smile.

"I've been to NASA before, and the color of your insulation is very different. Natasha said at this time, holding her son Angelo's small hand.

"That's because the composition of our insulation material is different," Yang Jie said with a smile: "Not only is the composition of the insulation material different, but our fuel tank processing method is also different." ”

The fuel tank is the main structure of the launch vehicle, which is composed of a cylinder, a fork ring and a bottom of the tank, but the bottom of the tank is a key component that affects the reliability of the whole rocket.

In the past, countries like the West used the technical route of thick plate heating spinning blank and CNC milling to manufacture the overall structure of the box bottom.

However, this method has a complex process, a manufacturing cycle of up to half a year, and 90% of the material is milled off, resulting in serious material waste, and these countries have always imposed an embargo on large-scale spinning equipment in China.

The bottom of the domestic active rocket tank generally adopts the structure of block forming and welding, but the structure size accuracy is poor, the scrap rate is high, and the reliability is also very poor.

The Machine Tool Research Institute of Huaxing Group has also developed a set of two-way controllable pressurized fluid high-pressure forming processing technology, which solves the problem of wrinkling and rupture of deep cavity curved surface parts, subverts the technical route used by NASA and ESA for decades, and breaks the blockade and equipment embargo of developed countries on the overall manufacturing technology of domestic rocket box bottom.

Such a set of equipment uses thin plates of the same thickness as the components to directly form the bottom of the thin-walled monolithic tank of the launch vehicle with a diameter of 3 meters, replacing the traditional multi-piece welded structure, completely eliminating the weld, and the comprehensive mechanical properties are much better than the traditional welded structure, which greatly improves the reliability of the launch vehicle.

This is mainly due to Yonghan Aviation Technology's accurate grasp of the characteristics of this aluminum alloy material and the technical strength of the Machine Tool Research Institute in high-precision molds.

The equipment developed by the Machine Tool Research Institute heats the aluminum alloy sheet and extrudes it into shape, and then relieves the stress.

This set of sheet fluid high-pressure forming machine is currently the world's largest sheet hydroforming machine, the forming force and high-pressure liquid volume are several times of the largest equipment of the same kind in foreign countries, one molding, greatly improving the efficiency.

Yang Jie has always liked to find another way in the technical route, as long as he recognizes the things, the whole company will do their best to complete his goals.

After a while, everyone came to the processing workshop of the rocket shell, the shell with a diameter of nearly 4 meters and a length of more than ten meters was transferred from the large vacuum ion evaporation equipment at this time, and the shell flashed with a purple metallic luster.

"The color of this shell is so beautiful!"

Natasha said.

"This is a layer of thermal barrier coating evaporated on the rocket shell, which can allow the aluminum alloy inside to withstand the high temperature of thousands of degrees when the rocket is flying, and it also greatly reduces the cost. ”

Yang Jie said with a smile.

"This thermal barrier coating material is expensive, isn't it?"

Natasha asked.

"There are no precious metals in this superalloy material, and the preparation cost is relatively cheap. ”

Yang Jie said with a smile.

"As far as I know, now NASA is also developing composite rocket shells, why are you still using aluminum alloys?"

Adam Cohen asked.

"Although carbon fiber does not melt, the resin is destroyed at a certain temperature, so usually aluminum or carbon fiber materials need a stable operating temperature, which is limited to around 150°C. ”

Yang Jie said with a smile: "You can only make some short trips within this temperature, maybe you can exceed the limit, to 177 °C, and then try hard to about 204 °C, but at 204 °C, you really reach the limit." In this case, the material will weaken, and some carbon fibers will shrink in strength even though they can withstand 204°C. ”

"What's more, the cost of carbon fiber is now hundreds of dollars per kilogram, and there is a scrap rate of about 35%, and some of them are unusable in the process of cutting fiber, so the actual cost is closer to more expensive per kilogram, and the cost of our aluminum alloy is only 8 dollars, and the cost of thermal barrier coating insulation interlayer process is also much cheaper than high-tech materials including aluminum-lithium alloy and titanium. ”

Yang Jie said with a smile: "The use of materials is not the newer, the more unique, the stronger a certain feature is the better, I hope to fully select the existing materials under the premise of full understanding, to ensure more efficient and extensive use." ”

He paused and said: "Actually, I still want to use a lot of lighter materials such as stainless steel, but this material still needs to be reformulated to improve the stainless steel that has 12% to 18% ductility even at minus 330 degrees Fahrenheit, but this formula has not been developed yet, so we use mature aerospace aluminum alloy materials for the time being." ”

Osside next to him said at this time: " Mr. Yang is a commercial and technical wizard, before building the rocket let us calculate and analyze, if we want to use composite materials, the rocket upper stage must use a variety of performance specifications of carbon matrix composite materials, in order to control the temperature of the alloy rocket body at a reasonable standard, processing a variety of composite materials will make the rocket to achieve the manufacture of extremely cumbersome, but also completely inconsistent with Mr. Yang's original intention to turn the launch vehicle into a civilian airliner as cheap as a means of transportation, so we are to use the cheapest materials as much as possible, and then coat a very thin layer of thermal barrier coating to achieve the design goal。 ”

Natasha glanced at Yang Jie with a smile: "This matter has been confirmed since I met him." ”

Osside and Ban Zhinong and the others all laughed.

This time, the big boss pulled Natasha and Adam Cohen over, although the big boss didn't say anything about their relationship, but a blind man could see that the big boss and the Hollywood star were "qing ren" relationship, and this Natasha lady also gave birth to very beautiful mixed-race twins for the big boss, which really made people sigh -

The private life of the big boss is really exciting!