13.82 billion years ago, in the first second after a dazzling silent explosion, many things happened at the same time. The temperature is decreasing, the space distance is expanding, and the four major forces are gradually decomposing. 380,000 years later, electrons and nuclei combine to become atoms, and then the first element in the universe was born, that is, hydrogen, which accounts for as much as 91.2%.
was born the earliest, and has a light body, like a legendary elf. After being combined with oxygen, only pure water is produced, making it a super potential stock of clean energy. In another way, hydrogen element is promising in the future.
Clean Energy - Single Atomic Hydrogen
But as early as 1766, the famous scientist Cavendish prepared hydrogen . Hundreds of years have passed, what has made hydrogen still not reach its peak and become the mainstream leader? Because of the small hydrogen in industrial applications, there are too many past studies.
The expensive giant ship will sink 140 ships per month; the Bay Bridge extending Interstate 80 will almost be scrapped if you accidentally. Chemists have spent a lot of effort to tame this naughty element from wild to domestic breeding. So, why is hydrogen so amazingly destructive?
Bridge damaged by hydrogen embrittlement
During World War II, the US military decided to upgrade its transportation equipment in order to improve transportation efficiency. 2710 Liberty Ship Freewheel debuted in a gorgeous manner. These ships have low cost and short construction periods, and can carry about 5,500 tons of cargo at a time. The US military has placed unlimited hope for the future of these ships.
However, the good times did not last long. Among the less than three thousand freewheels, 1,500 had cracks that could not be repaired during navigation. It was winter at that time, and under the low temperature, some free wheels broke into two pieces without warning. Not to mention the lost materials, many soldiers had to struggle to survive in the vast sea, which had a serious impact on the logistics supply of the US military.
The most famous one happened on January 16, 1943, when the calm darkness that night was cut by a loud bang, and the undelivered tanker S.S. Schenectady cracked in half in the shipyard. The tanker was the first order the shipyard took on. As soon as the news came out, everyone in the seat was shocked.
Some people also comfort themselves. Maybe the technology of this factory is not mature enough? The ruthless fact slapped them in the face two months later. Another Freedom Ship, the Esso Manhattan, also cracked when entering New York Bay.
Freewheel the Esso Manhattan number
It would be fine if one of two ships died before they could succeed. The problem is that these freewheels seemed to have made an appointment and sank at a speed of 140 ships a month. The construction cost of the Free Ship was about 2 million US dollars per ship at that time, equivalent to the current US$36 million. This veritable act of throwing money into the water and hearing it sounded, no matter how rich the family's wealth was, it would not stand . What exactly is the problem with
? Due to technical limitations, no one knows the answer during the war. However, as long as your mind does not fall into decline, there are always more ways than difficulties. The American slapped his head and said, since it was broken, then I just need to patch it up. Sewing and repairing, three years and three years.
So the US shipyards reached an agreement to promote the research on the cause of the accident first. Let’s use steel plates to patch the cracks to prevent the ship from continuing to crack. This inspiration from repairing clothes is quite effective. After practice makes perfect, these anti-cracking steel plates have their official name - crack-repellent rivets.
Shield patching and repairing - crack-stop rivet
After comprehensively promoting patch technology, the monthly sinking of the Freewheeler dropped to 20 ships/month, becoming one-seventh of the previous one, which is really gratifying. After World War II, the Americans who were finally idle began to sum up the lessons. The thing about the sinking of the free wheel floated to the surface earlier than the free wheel at the bottom of the sea.
Physicist at the U.S. Naval Research Laboratory , George Irving, decided to study the data of the Freewheel. Finally he found the biggest reason for the shipwreck - hydrogen.
It is also a big deal for the senior management of the US military. Some new welding technology was put into use in the early 20th century, such as manual arc welding and welding rod welding.During welding, the heat from arc or acetylene combustion will melt the metal, causing the two pieces of metal to weld to one piece and cannot be divided for a moment.
0 The introduction of welding technology in the early 20th century
Before the emergence of electric welding technology, the metal plates of the splicing ships were riveted technology, and they were riveted to be killed by digging holes, putting rivets, and starting. It looks very simple, but in actual operation, specially trained technicians need to determine where to rivet, how many rivets, and how to rivet.
The wages of these technical workers account for one-third of the labor cost of ship assembly. In addition, metal plates need to be overlapped during riveting, the weight of the hull and the cost of raw materials are ascending hand in hand, and the speed of spending money in war is faster than throwing it into a fire. Coupled with the increase in the demand for supply on the front line, there is not enough riveting workers.
The Federal Maritime Commission slapped his head and asked American shipyards to use welding instead of riveting. The fruit of victory was quickly picked. Between 1930 and 1937, US shipyards built 71 ships. After using electric welding technology, between 1939 and 1945, a total of 5,777 ships were shipped in the United States.
The speed of manufacturing a freewheel is amazing, and it can be completed in 5 days. But all the gifts given by fate are secretly bidding for the price. What people at that time didn't know was that single atomic hydrogen would be produced during welding, and during the process of synthesising two steel plates into one, occasionally had atoms with rebellious personality and refused to run to the right position.
In the originally neat metal atom array, misalignment and gaps will occur. Scientists call it "dislocation". When you look at the naughty single atom hydrogen, you are so coincidental that you also like to force obsessive-compulsive disorder to death. It drills to the atom where the dislocation occurs and calls friends to form hydrogen.
special situations arising from welding - dislocation
dislocation is originally a weak area of metal materials. When is finished and the material is gradually cooling, the hydrogen begins to miss the free air outside. They will unite to attack the weaknesses, destroy the metal structure, and make the metal bloating and become brittle. This phenomenon is named hydrogen embrittlement .
Don’t underestimate it. Sometimes hydrogen can accumulate into a high pressure of 18.7 megapas in metal, which is 187 times that of the surface air pressure. There is another situation in . The hydrogen atom absorbed by steel at high temperatures may form methane gas with carbon atoms in the steel, making the steel decarbonized and brittle, which is called hydrogen corrosion .
metals become fragile, and after their solid nature is corroded, their ending is destined - cracking. The heavy objects transported by tankers and the slap of waves will accelerate the expansion of cracks. What's even more terrifying is that metals that have undergone hydrogen embrittlement or hydrogen corrosion seem to have nothing to do on the surface. It is easy to avoid quality inspection and will not arouse the alertness of manufacturers and users at all, which lays hidden dangers.
Users cannot predict when and where the giant under their feet will ruthlessly crack, allowing the cold sea water to slap randomly on their faces, playing with the passengers' heartbeat.
As early as 1875, W. H. Johnson discovered that love and people have a heartbeat. However, before the large number of incidents in the free wheels, everyone did not know that hydrogen embrittlement had such strong destructive power. After summarizing the reasons for the "sickness" of the Freewheel, George Irving pioneered a new discipline that specializes in analyzing fracture mechanics and material strength.
The construction and manufacturing industry have finally begun to pay attention to the hydrogen, which is not astonishingly beautiful as the first element of the universe. Unfortunately, although we know what hydrogen embrittlement is, so far, researchers have not fully understood the principle of hydrogen embrittlement.
Hydrogen embrittlement phenomenon
Due to the willingness of hydrogen elements, we cannot predict when and where the materials will experience hydrogen embrittlement, so the best way is to prevent it. We will study hydrogen embrittlement without any thorough research, and all roads lead to Rome. Let’s study electric welding instead.
After long-term demonstration and experiment, the reason for single-atom hydrogen is that the arc and cellulose coating on the surface of the welding rod will come into contact with the water vapor in the air. In this regard, people first decided to improve the resistance of welding rods, so low hydrogen welding rods emerged. It can reduce the generation of single hydrogen atoms and is suitable for welding high-strength steels.
Just one wave is flat and the other is rising again. Sometimes hydrogen diffuses into the metal during the manufacturing process, and the process of electroplating and cleaning may also produce single-atom hydrogen.
For example, some bolts are often made of cadmium plating to prevent corrosion. Single-atom hydrogen is so small and so pervasive, so naturally I will not miss the opportunity to drill in when using cadmium plating.
Therefore, the US Air Force had to set standards for low hydrogen embrittlement cadmium plating and required contractors to strictly comply with it. In order to remove hydrogen, the supplier of bolts usually performs heat treatment processes such as annealing of the bolts after cadmium plating to allow hydrogen to escape from the bolts. In addition to these, there is another method called vacuum high-temperature smelting.
Vacuum high-temperature smelting
As the name suggests, when smelting and processing metal raw materials, the outside world is kept vacuum, and hydrogen will naturally not be able to penetrate into the metal, but will be sucked into the environment. In order to avoid hydrogen embrittlement of "virus" invading materials, researchers have been thinking about it.
After the harmless mask of hydrogen humans and animals was taken off, the disaster caused by hydrogen embrittlement was relatively reduced, but it did not completely disappear . For example, the Bay Bridge mentioned at the beginning of the video. In 2013, the United States finally decided to renovate and rebuild the new bridge in the eastern section of the San Francisco-Oakland Bay Bridge, which was damaged in the 1989 earthquake.
The San Francisco-Oakland Bay Bridge under repair
7.2 billion investment makes this project one of the most expensive projects in California's history. The rebuilt new bridge will surpass the Golden Gate Bridge and become another new landmark in the United States. What is particularly striking is that the most important eastern section of the new bridge is built by China's Shanghai Zhenhua Heavy Industry.
During the test before opening the bus, careful engineers discovered the problem. The safety bolts responsible for erecting the bridge deck on the cement columns appeared after two weeks of testing and 30 of the 96 safety bolts were broken. The reason was that hydrogen was causing trouble.
finally replaced the bolt and cost five times the estimated amount. Hydrogen embrittlement took away $25 million without hesitation. The public opinion was in an uproar, but the money had to be spent. After all, if the Bay Bridge becomes a broken bridge, there is no beautiful and kind-hearted woman who borrows an umbrella from the American people on a rainy day.
Hydrome's "bad temper" not only harms others, but also hinders its own development. Under the shadow of hydrogen embrittlement, long-term storage of high-pressure hydrogen with metal materials is equivalent to raising an irregular time bomb, a typical case occurred in France.
French metal hydrogen tank exploded unexpectedly
In 1988, a 3 kiloliter metal hydrogen tank exploded, and none of the property within a radius of half a mile was spared. But it was put into use in 1939, and no one could guess that after half a century of peace, hydrogen still had an expensive firework.
Although the combustion product of hydrogen is only water, these troubles caused by hydrogen have made commercial technologies that can safely compress hydrogen fuels difficult to produce, and the cost of hydrogen transportation pipelines remains high. Most importantly, hydrogen diffuses extremely fast and runs upward with light weight. So in an open area, it will soon spread into the sky and the probability of explosion is not high.
But it's different in the tunnel, and the United States has experimented. When the gas storage tank is quickly discharged according to federal requirements, the explosion concentration will reach within 1 meter after hydrogen leaks for 1 second; after 2 seconds, the explosion concentration will reach within 3 meters.
Good luck hydrogen performs a fire spitting out. If you are not lucky, lighting it in 1 second may kill the person in the car. After 3 seconds, lighting it within 10 meters will make you happy. If there was another fuel truck driving behind at this time, the picture would be unimaginable.
Some viewers will say, isn’t hydrogen spreading faster than fuel? No, no, the other side of spreading fast is that under the same explosion, gasoline has more than ten minutes of escape time; natural gas has few minutes of escape time; hydrogen gives you two seconds.
Ye Shengji, deputy secretary-general of my country Automobile Industry Association, once said that hydrogen fuel vehicles are still in the initial and cultivated stages in the advancement of industrialization, and they are quite tactful.
hydrogen element, produced by the Big Bang of the Universe, is also limited by the explosion. It is a veritable first element, but it has not become the first energy source for a long time.However, human beings are always curious about technology and desire to explore. Perhaps in the near future, we can make the energy "hydrogen" one, and the stable "hydrogen" is a long time.
