The team led by Professor Hong Feiyi of the Department of Materials Science and Engineering at National Cheng Kung University has established one of the few laboratories in China that can evaluate hydrogen embrittlement of metals. The laboratory allows hydrogen to attack specific areas of the material, which is called concentrated hydrogen treatment.

The team led by Professor Hong Feiyi of the Department of Materials Science and Engineering at National Cheng Kung University has established one of the few laboratories in China that can evaluate hydrogen embrittlement of metals. The laboratory allows hydrogen to attack specific areas of the material, which is called concentrated hydrogen treatment.

Hong Feiyi said that using water electrolysis to produce hydrogen and oxygen as energy, without the pollution and carbon emissions caused by petrochemical raw materials, is considered to be the cleanest energy in the world in the future. However, there are still many problems to be overcome in current development. Among them, "hydrogen embrittlement" may cause major safety problems, and there is still no complete solution to the problem in the world.

He pointed out that hydrogen atoms are extremely fine atoms that can tunnel through any material. When covered by a material, hydrogen and the material will produce hydrogenation and brittle cracking, which is called hydrogen embrittlement. Once the storage tank or pipeline has cracks due to hydrogen embrittlement, hydrogen will leak out and cause an explosion. Similar accidents have occurred around the world in the past, causing people to have doubts about the development of hydrogen energy.

Hong Feiyi has more than 20 years of experience in researching various metals. He said that among various stainless steel materials, 309 and 316 stainless steels were previously believed to have excellent corrosion resistance and were widely used in acidic, alkaline and thermal environments. They were also used in the hydrogen energy industry. However, they are not only unable to resist hydrogen embrittlement, but also have poor strength and wear resistance. If used in hydrogen-powered vehicles, they will be difficult to resist strong impacts in the event of a car accident. Moreover, after being used to a certain extent, hydrogen embrittlement may occur, and hydrogen may leak out and explode.

The team led by Professor Hong Feiyi of the Department of Materials Science and Engineering at National Cheng Kung University has developed a hydrogen-resistant steel 416B, as well as a hydrogen-resistant welding material 420L.

Currently, glass fiber is mostly used as a material for storing hydrogen. Hong Feiyi said that glass fiber is in the shape of a barbed hook. Once it is inhaled into the lungs, it cannot come out and is easy to cause cancer. It is not a good material. At the same time, it has poor hardness and is not impact-resistant.

During his research, he discovered that 416 stainless steel used in the military industry is not only as resistant to acid and alkali corrosion and rust-free as 309 and 316, but also has better strength and hardness. Unlike 309 and 316, it is non-magnetic, but has good magnetic properties and can be connected in series to form hydrogen-free electromagnetic steel. After heat treatment, the original equiaxed crystals are transformed into a strong needle-rod structure, which is 416B, which can resist the tunneling of hydrogen and "can be almost perfectly applied in the development of hydrogen energy". It can be used to store hydrogen, or to make various hydrogen-resistant valves and fasteners.

The pipelines of hydrogen energy equipment need to be welded. He said that welding points are more easily attacked by hydrogen. The team has long cooperated with Tainan welding rod manufacturer Shourui. In the process of developing non-hydrogen steel, they also found the welding material 420 produced by Shourui. As long as it is dehydrogenated and becomes 420L, it can avoid hydrogen attack.

The team led by Professor Hong Feiyi of the Department of Materials Science and Engineering at National Cheng Kung University has established one of the few laboratories in the country that can evaluate hydrogen embrittlement of metals. The laboratory is conducting hydrogen embrittlement tests on the only electric high-temperature tensile fatigue testing machine in Taiwan.

In order to verify the hydrogen resistance of hydrogen-free steel, the team built from scratch one of the few laboratories in the country that can evaluate metal hydrogen embrittlement. Hydrogen is allowed to attack specific areas of stainless steel materials, which is called concentrated hydrogen treatment. The cumulative time can reach several months, and then hydrogen embrittlement investigation is carried out. The laboratory is equipped with the only electric high-temperature tensile fatigue testing machine in the country, which can conduct immediate investigations on metal hydrogen embrittlement. Hong Feiyi said that due to the high danger of hydrogen, it is quite difficult to build a safe laboratory. It was successful after repeated testing with the combination of chemical engineering talents on campus.

After testing, it was found that the hydrogen tunneling resistance of hydrogen-free steel is more than 1 times that of other industrial-grade stainless steels, and its strength and hardness are higher than those of traditional stainless steels. When used in hydrogen-powered vehicles, it is not afraid of collisions or hydrogen embrittlement. When used in hydrogen fuel transportation pipelines, it can also improve transportation efficiency and safety.

The team led by Professor Hong Feiyi (second from right) of the Department of Materials Science and Engineering at National Cheng Kung University has developed a "hydrogen-free steel" that can resist hydrogen tunneling. The picture shows the team members: postdoctoral researcher Wu Boding (first from right), graduate student Lu Zhewei (second from left), and graduate student Huang Yuzhen (first from left). In the middle is the laboratory's only electric high-temperature tensile fatigue testing machine in Taiwan.

Hong Feiyi said that with two years of hard work by researcher Dr. Wu Boding, graduate students Lu Zhewei and Huang Yuzhen, the laboratory has established integrated hydrogen testing and hydrogen embrittlement fatigue testing, and assisted in the analysis and evaluation of various welds, and established the application data of National Cheng Kung University's 416B non-hydrogen steel. At present, the relevant papers have been published and the patents are being applied for. National Cheng Kung University has demonstrated its highlights in hydrogen energy technology and laid a new foundation for the application of non-hydrogen steel.

Six HyNet Projects Including Hydrogen Receive Go-Ahead