The difficulty in building LNG ships lies in the characteristics of natural gas.

To transport or store natural gas, it must be compressed into a liquid, that is, liquefied natural gas, so that it can be easily transported and stored.

To turn natural gas into a liquid, it needs to be cooled to -162°C and stored in storage tanks on LNG ships for transportation.

This brings about an extremely difficult technical problem to overcome - at such a low temperature, steel will become brittle and easy to crack, and a slightly defective storage tank may cause a devastating explosion due to gas leakage, and there is a "sleeping hydrogen bomb"

called.

Therefore, the liquid cargo containment system in LNG ships has become an important technical threshold.

There are two common liquid cargo containment systems in the world, the French membrane type and the Norwegian self-supporting type. Both technologies are European and American monopoly technologies.

After entering the 1990s, Japan and South Korea took over the baton of world shipbuilding. In 1994, South Korea built its first LNG ship, starting the competition with Japan.

This time, Yao Yuan obtained the membrane-type liquid cargo containment system technology from Hyundai Heavy Industries as early as the year when China and South Korea established diplomatic relations. After two years of research and training of technical workers, Directional Shipbuilding built it half a year earlier than Hyundai Heavy Industries.

lng ship.

What Directional Shipbuilding is building is the first mass-produced 180,000 cubic meter LNG ship ordered by Yuanhai Ocean Shipping Company. An LNG ship of this specification has a full load displacement of about 120,000 tons and a length of more than 300 meters. It is a real big thing.

.

At this time, Oster saw the giant hull section being built in the huge factory. Intuitively, the most obvious difference between the giant section construction method and the segmented shipbuilding method is that the number of segments in the former is greatly reduced, because the size of the segments

increased.

For example, the 120,000-ton LNG ship being built is obviously divided into only thirteen segments, which means that the weight of these segments is several thousand or even tens of thousands of tons.

It's extremely difficult to put together such heavy segments!

Yao Yuan beside him said lightly, "We are developing a 1,500-ton gantry crane. With floating cranes and other equipment, we can build 5,000-ton giant sections. In this way, the time occupied by the dock will be shorter."

"1500-ton gantry crane..." Oster couldn't think clearly. Is this still the ancient oriental country that I remember as very backward?

Why do they give people the impression of a developed country that has mastered many of the world's cutting-edge technologies?

Gantry cranes are very important. Before the advent of the giant block shipbuilding method, the gantry crane with the largest lifting capacity was 900 tons. The current largest shipyard gantry crane is also 900 tons.

Yao Yuan almost emptied the Black Sea Shipyard, including the 900-ton gantry crane. After moving it back, he reverse-engineered one and now has two 900-ton gantry cranes.

Nowadays, most shipyards use the segmented construction method to build ships, dividing the entire ship into several small segments, prefabricating them in the workshop, and then assembling them in the dock.

This requires the use of gantry cranes. Small sections do not have high requirements for gantry cranes. Generally, those below 500 tons are sufficient.

However, the sturdiness coefficient of warships is much higher than that of civilian ships, especially the sea monster aircraft carrier. In order to achieve a certain sturdiness coefficient, the fewer segments the better when building an aircraft carrier. Since the emergence of aircraft carriers, after so many years of practice

, the limit that people can reach is 900 tons.

A section weighing 900 tons is already very large. Generally, shipyards do not have this capability. There are only three shipyards in the world using such gantry cranes, two in the United States and one in the Soviet Union. Even now, the shipbuilding industry in Japan and South Korea

The factory does not yet have a 900-ton shipyard gantry crane.

Newport News Shipbuilding in the United States has built more than half of the U.S. Navy's aircraft carriers. People can often see in news reports that the new aircraft carrier built by Newport News Shipbuilding has completed the installation of the bow bulb. This thing

The segment alone weighs 900 tons, requiring the world's largest gantry crane to complete the installation.

This is Newport News Shipbuilding taking a turn to show its strength.

Apart from the United States, only the Soviet Union at the time and the Black Sea Shipyard in Ukraine had a 900-ton gantry crane, which was almost a necessary equipment for building aircraft carriers.

but!

After the advent of the giant section shipbuilding method, the lifting requirements for gantry cranes increased, forcing port machinery companies to develop larger gantry cranes.

A shipyard gantry crane is not a simple crane. First of all, the width of large ships is very wide, such as aircraft carriers. The deck width is more than 80 meters, which means that the span of the gantry crane must be at least 100 meters. The larger the span, the same material and design will

The lower the weight, the smaller the lifting weight.

More importantly, the assembly of ship segments is a high-precision operation, which places extremely high requirements on the operating accuracy of the gantry crane!

By the second half of the 21st century, Western countries have lost the ability to build thousand-ton gantry cranes. All the gantry cranes they use to build warships must be bought from China, including the United States building new aircraft carriers and new destroyers...

…

Zhenhua Port Machinery, a wholly-owned subsidiary of Nanfang Industrial, was established as early as 1992. It took three years to imitate the 900-ton gantry crane at the Black Sea Shipyard. The 1,500-ton gantry crane they are working on is already close to

end.

Therefore, Yao Yuan can openly announce it in advance.

Oster walked towards the storage tank operation area. Obviously, he was very knowledgeable.

The most valuable and most difficult thing to build in an LNG ship is the storage tank. This thing is a complete contradiction - it must be able to withstand the low temperature of -162°C, and it must be strong and flexible. To put it bluntly, it is

It will work no matter what.

Scientists searched for materials and finally found that Invar steel was the only material suitable for building LNG storage tanks.

The special properties of Invar steel determine that it is an indispensable material for building large LNG plants and storage tanks, but it also determines its delicateness - 0.7 mm thick Invar steel, if you touch it with your bare hands, it will look like twenty

It will rust through in four hours.

This brings extremely high difficulty to welding, and it is no exaggeration to evaluate this difficulty factor.

First of all, welders need to wear special sheepskin sweat-absorbent gloves, which means that the feeling of the welder's hands is reduced. When welding such thin invar steel, a millisecond of hesitation will cause it to burn through.

Moreover, the entire interior of the tank is an irregular cube, and welders need to perform welding in various extremely uncomfortable postures, which adds to the difficulty!

Oster knows his stuff, precisely because what he wants to see now is the level of shipbuilding welders. That is not a job that ordinary welders can do. Welders who can weld invar steel are more valuable than scientists and are generals among skilled workers.

What level of Invar Steel welders a shipyard that has been established for several years can produce, and how many such welders it can produce, are directly related to the construction speed of LNG ships.

Oster glanced at Yao Yuan and couldn't help but said, "French workers work five hours a day and get two months of paid vacation every year. Welders who can weld Invar steel simply don't work in the company. Sometimes the company does the opposite."

Production must be arranged according to their schedule. Mr. Yao, do you know why?"

Yao Yuan smiled and shrugged, "Without welders who can weld Yinwa steel, it is impossible to build LNG ships."
Chapter completed!