As a powerful maritime force, aircraft carriers have become a symbol of the country's comprehensive national strength, but there are very few countries in the world that have aircraft carriers.
my country's aircraft carrier industry started in the 1970s. The first aircraft carrier was transformed from the Soviet Union's "Varyag" . Starting from the "Varyag" , my country's aircraft carrier industry has gradually developed Development path.
But when the Varyag was first shipped back to China, the aircraft carrier transformation plan was delayed, not because of funds, but because our country was unable to manufacture the special steel for the aircraft carrier. What kind of steel is this and why is it so difficult to manufacture?
The rusty Varyag, ultra-high corrosion resistance special steel
In the development process of our country's navy, the service of the aircraft carrier is an important milestone. When our country visited the United States' aircraft carrier for the first time, the construction of the aircraft carrier was included in China's national defense construction plan.
But China was very poor in the 1980s, and it was difficult to overcome the financial hurdle alone, let alone the technological blockade China faced. After the disintegration of the Soviet Union in 1991, Ukraine inherited the Soviet Union's large aircraft carrier Varyag.
However, Ukraine, which lacked funds, had the shell of an aircraft carrier, but had no funds to continue building it. By the second year, it had no choice but to give up the construction of the aircraft carrier and decided to sell the aircraft carrier. Then China's aircraft carrier career ushered in a transformation. machine.
Although the funding problem was still difficult, with the help of patriots and after some negotiations, the Varyag finally embarked on the long journey to China.
After three years and encountering many obstacles, Varyag finally arrived in the Gulf of China, ushering in the dawn of aircraft carrier development in China. When took over the Varyag in our country, the Varyag had been in the water for eight years. Counting the time when it started to be built, it took nearly 20 years.
Under normal circumstances, there is almost no steel that can not turn into a pile of scrap metal without repair, not to mention that Ukraine has dismantled the Varyag beyond recognition.
So the Varyag that came to China only had a rusty aircraft carrier shell. The weapons and electronic systems on the aircraft carrier had been dismantled to pieces, with no engines or propellers.
According to the memories of the captain of Liaoning ship , when they saw the Varyag for the first time, their inner excitement was immediately overshadowed by disappointment, because what they saw was a rusty and tattered aircraft carrier. Questions even arise in my mind: Can such an aircraft carrier really be repaired?
But the Varyag soon gave everyone a surprise. Even after 20 years, when the rust on the surface of the aircraft carrier was wiped away, it was still shiny, just like a newly built aircraft carrier. This is the power of Soviet special steel, which has ultra-high corrosion resistance.
As a large ship, aircraft carriers have extremely high requirements for the quality of steel, which must be corrosion-resistant, high-strength, high-temperature resistant, and anti-magnetic.
The special steel used by the Soviet Union perfectly meets the conditions. The Soviet Union uses high-strength nickel-chromium alloy steel with a yield strength of 500-600 MPa to build aircraft carriers. The main body of the Varyag uses 590MPa-level AK -25 steel, and the protective part uses 700MPa grade steel.
India's Vikrant aircraft carrier, during the construction process alone, had its bottom severely corroded by seawater. However, the Varyag has remained in good condition after several years.
Another powerful feature of the Varyag's use of steel is its degaussing ability. This is a necessary condition for the construction of steel for aircraft carriers. Generally, metals will have a certain intensity of magnetic field, but aircraft carriers must be degaussed because aircraft carriers will encounter mines while sailing in the water.
The induction of a mine is different from that of a mine. The mine has a magnetic needle . When the metal is close to the mine, the mine's magnetic needle will swing. This is used as a signal to connect the electric detonator in the mine, thereby detonating the mine. In order to avoid mine attacks, almost all warships are made of degaussing metal, and the degaussing function of aircraft carriers is even more important.
Normal aircraft carriers need to be degaussed after being put into service, otherwise the metal that has been in disrepair for a long time will emit stronger and stronger magnetic fields, which means that this aircraft carrier will soon be unable to continue to serve.
However, during the physical examination of the Varyag, there was no trace of a magnetic field. It still maintained good performance during the eight years it was left unattended, which shows how high the Soviet Union's industrial development level was at that time. But such powerful steel has become the first difficulty China encounters in transforming its aircraft carrier.
Special steel that is difficult to reproduce, China's steel industry upgrade
The Liaoning ship is mainly modified from the Varyag, but if the Varyag is to be modified, it first needs steel with a comparable quality level.
Different parts of the aircraft carrier have different thickness, type and requirements for aircraft carrier steel. The above-water part will be impacted by waves and changes in water pressure. requires the use of submarine pressure-resistant plates with a thickness between 23mm and 28mm, but the underwater part is extremely strict. .
First of all, it must be corrosion-resistant, and secondly, it must be able to resist attacks by torpedoes and missiles , so the thickness of the steel is as high as 150mm-230mm.
The steel inside the aircraft carrier is relatively thin. The hangar deck is about 38mm, and the thickness of the decks between the other layers is only 4-18mm. The thickest is the armor plate that protects the aircraft carrier. The thickness of reaches 330mm. This is also the thickness of the aircraft carrier. The most high-tech steel used in flight decks.
Because it is in contact with the carrier-based aircraft , it must meet the requirements of large layout, high strength, and high temperature resistance. Temperature changes at sea and huge waves also need to be considered, so the flight deck must be resistant to low temperatures and corrosion. But it cannot be too thick, because must maintain the center of gravity of the aircraft carrier and must have degaussing capabilities, which means it cannot be detected by local places.
The Varyag has all the advantages, but not all countries can reproduce the special steel used by the Soviet Union.
was a great challenge to China at that time. It is precisely due to the lack of special steel that the Varyag has been stranded in the Gulf of China for a long time. Because there were not many countries in the world that could produce this kind of steel at that time, HY-100 and HY-80 from the United States were the best alternatives to the Soviet special steel.
But China does not have the funds, and the United States may not be willing to sell it. China once tried to buy blocking cables for aircraft carriers from Russia, which is also an exclusive technology of the United States and Russia, but was still rejected.
Now special steel has become the first bottleneck in the development of China's aircraft carrier. The past technical level is no longer sufficient, and the only way is to upgrade technology.
To replace the steel of the Varyag, hundreds of tons of symmetrical spherical flat steel are needed. This is a kind of steel with a spherical head and a flat body. It is an essential steel in the fields of shipbuilding and bridge building.
But China did not master this kind of technology at the time. Due to the urgent demand for steel, China's Anshan Iron and Steel Group took over the important task of developing special steel.
Ansteel Group is the cradle of China's steel industry. When China first decided to build the Yangtze River Bridge, Ansteel Group took over the mission of producing bridge steel, produced bridges that met the design requirements from scratch. steel.
But this time, the same problem was handed over to Anshan Iron and Steel Group. Starting from the development of symmetrical bulb flat steel, Anshan Iron and Steel Group established a professional technical team, led by researcher Zhou Dan with 24 years of experience in the field of surface ships, to overcome the production difficulties of bulb flat steel.
However, the symmetrical spherical flat steel has a special shape and a huge difference in size. It is very difficult to just roll and form. At that time, Angang did not have a dedicated production line and could not produce quantitatively.
So the technical team had to fix the roots of the flat bulb steel on the heat treatment rack to prevent the flat bulb steel from deforming.
In the following time, Zhou Dan's team continued to conduct in-depth research on steel upgrading, adopted rapid induction heating technology, designed and developed a quenching production line, and determined multiple parameters such as power supply mode and heating mode. finally developed a hot-rolled The rapid induction heating technology of flat bulb steel has achieved a technological breakthrough in flat bulb steel. In the next year and a half,
successively provided 200 tons of aircraft carrier steel to Dalian Shipyard , , where the Varyag was renovated, and made a huge contribution.
As a result, in addition to flat bulb steel, China Anshan Iron and Steel Co., Ltd. has also begun a comprehensive upgrade of other steel products. It can be said that in this technological breakthrough battle, China's steel industry chain has achieved a comprehensive technological upgrade. But this is not the biggest problem that Anshan Iron and Steel Group needs to solve.
The challenge of deck steel, the birth of the thick plate rolling mill "the king of rolling mill "
With the efforts of the technical team, most of the steel for the construction of aircraft carriers was produced. But this only solved some of the technical problems. In the process of rebuilding the Varyag, my country did not replace all the special steel made by the Soviet Union. However, after the successful reconstruction of the Liaoning ship, my country's plan for the Shandong ship was put on the agenda.
This time, every piece of steel needed for the aircraft carrier needs to be built independently, including the most important steel in the aircraft carrier-deck steel. This time, still took over the challenge of Anshan Iron and Steel Group.
The requirements for deck steel were mentioned earlier. The more requirements, the higher the difficulty. Today, there are only 5 countries that can produce aircraft carrier deck steel, and China is one of them. mainly has two series: HY high yield strength steel and HSLA high strength low alloy steel.
Among them, HY steel can be divided into HY-80, HY-100 and HY-130, yield strength is 550MPa, 690MPa and 890MPa respectively, and HSLA steel has HSLA-65, HSLA-80, HSLA-100 and HSLA- 115 four varieties, the yield strengths are 449MPa, 549MPa, 689MPa and 795MPa respectively.
The USS Ford's deck aircraft carrier uses HSLA-115 steel with a strength of 795MPa. - square centimeters can withstand an impact of nearly 8 tons.
Compared with HY series alloy steel , the strength of HSLA series steel is that it eliminates the preheating process, which corresponds to the development of ultra-low carbon, ultra-pure steel smelting, controlled rolling and controlled cooling and other metallurgical technologies. . Because the higher the strength requirements of steel and the greater the carbon content, welding becomes more difficult.
In the construction process of aircraft carriers, one-third of the work is welding steel plates. In order to save time, the single steel plate area is very large, but the performance requirements are extremely strict, because the steel plates must have strong bullet resistance, so is a headache. The tail strength deviation does not exceed 10 MPa, and the impact toughness of and is above 250 J.
With the development of technology, the emergence of HSLA series steel has gradually solved the welding problem. If conditions permit, almost all aircraft carriers will use HSLA series steel. However, no country will share this key technical issue.
If China wants to build its own aircraft carrier, it must develop domestically produced steel. Anshan Iron and Steel Group once again launched a new round of fierce battle over the technical problems of deck steel. In this production process, First Heavy Industry Group joined the research and development team and participated in another technical upgrade - the 5500mm rolling mill.
This is the widest rolling mill in the world, covering an area of 200 meters long and 35 meters wide. It is composed of more than 40 single-machine equipment and more than 100,000 parts. Jointly designed by 1st Heavy Machinery and the German SMS company, and independently manufactured by 1st Heavy Machinery, has a rolling force of up to 100,000 tons, making it the king of rolling mills in the world. The steel plate extruded by
has a width of up to 5.5 meters and a length of more than 40 meters. The deck steel produced from this king of rolling mills is four times larger than conventional steel plates. The performance is similar to HY-100 or HSLA-100, reaching 690MPa, second only to the steel used in the deck of the USS Ford.
Thanks to the efforts of the technical team, China’s aircraft carrier deck steel has finally been nationalized.China has become the third country in the world with deck steel technology.
Anshan Iron and Steel’s contribution does not end there. In addition to deck steel, Anshan Iron and Steel has completed the production of special steel in only one year that took ten years to produce in the past. Currently, 70% of the special steel required for aircraft carriers comes from Anshan Iron and Steel Group. The speed of Anshan Iron and Steel's steel production has also greatly accelerated the research and development of domestic aircraft carriers.
In 2017, China's Shandong ship was successfully launched into service. It only took 6 years from construction to official entry into service. In 2022, China's Type 003 aircraft carrier will also be launched soon.
Amidst the doubts one after another, China's technical team created an industrial miracle belonging to China with China's speed and , breaking other countries' technological blockade against China. To this day, there are still not many countries with aircraft carriers, mainly due to difficult technical problems such as steel.
As mentioned earlier, the steel used in the Indian aircraft carrier is not corrosion-resistant. More than 20 years have passed since its construction in 1999, and it is still in the process of construction. The aircraft carrier it uses mainly relies on the United States and Russia, and was purchased from Russia. vikramaditya .
In the development of all special steels for aircraft carriers, the United States is undoubtedly the first. The HY series and HSLA series were developed by the United States. For example, the French aircraft carrier Charles de Gaulle uses American HY-80 steel, and the world The highest yield material strength is the Russian AK series nickel-chromium plus titanium alloy steel, and the yield strength is as high as 1000MPa.
However, the United States and Russia have always been industrial powers. has always been at the forefront of military research, but this also means technological blockade.
China’s aircraft carrier business has achieved technological innovation amid layer after layer of technological blockade. To some extent, also proves the strength of China's industry. Even though there is still a gap between China's deck steel and the steel used in the United States, China's aircraft carrier development technology has made great progress.
From the first time the captain of the Liaoning saw the Varyag to the launch test of the Type 003 aircraft carrier, China's aircraft carrier development has opened a new chapter in more than 20 years. From steel to power system, has achieved comprehensive technological leap.
Up to now, Baosteel has also joined the ranks of steel manufacturing, providing steel for the construction of China's aircraft carriers. In subsequent research and development, special steel with better performance may appear, and this cannot be separated from the unremitting efforts of technical personnel. .
