Oriented Silicon Steel: To Clank the Iron Bone Forged by Hammer and Hammer

Put “Mingmen” in our own hands

Among the various large transformers of the Three Gorges Hydropower Station and the West-East Power Transmission, there is a special kind of steel: oriented silicon steel. It is the “core” manufacturing material in the transformer and is called “craftwork in steel products”.

The surface structure of the steel plate is like a map with blocks stitched together. The researchers told reporters that this irregular “map” is the grains of oriented silicon steel. After pickling, a diamond-shaped etch pit will be found under the microscope observation. The direction is exactly the same as the rolling direction of the steel plate.

A unique approach to low-temperature manufacturing subverts traditional processes

Before 2008, only a few steel companies in the world were capable of manufacturing oriented silicon steel. China is the world’s largest importer of oriented silicon steel, especially high-grade oriented silicon steel used for high-performance transformers, almost all rely on imports.

China has gone through all kinds of difficulties in tackling the difficulties of silicon steel products. The traditional high-temperature manufacturing process requires a reheating temperature of nearly 1400 ° C. The billet melts and “slag” appears. Like ice hangs on the eaves of winter, production is very difficult. In tackling the difficulties, the scientific research personnel have thoroughly studied the traditional high-temperature process method. After hundreds of trials, they have independently developed a low-temperature manufacturing process, which has lowered the temperature of the traditional heating furnace by more than 200 ℃ The manufacturability of oriented silicon steel.

However, the technological breakthroughs only reached the foot of the mountain. In the process of heading to the top of the mountain, there are also many difficulties waiting for them to independently research and develop production equipment, production line design and construction, and industrialization trials. There is also a big gap between the laboratory and mass production. The comprehensive qualified parameters of the first batch of oriented silicon steel hot rolled coils were only 2.4%, but the experimenters were not alarmed. It is precisely because of the courage to innovate, plan ahead, and practice that the technical risks have been released in advance, laying a solid foundation for the successful manufacture of oriented silicon steel.

A sword in ten years, climbing a new peak of high magnetic orientation silicon steel

In the second half of 2008, low-temperature and high-magnetic-oriented oriented silicon steel and laser-marked oriented silicon steel products were successively launched and mass production was realized. In the following 8 years, new high-end oriented silicon steel products were first used in major national projects such as the “Three Gorges” and “West to East Power Transmission”, which broke the monopoly position of imported products in the field of ultra-high voltage, ultra-high voltage AC and DC transformers; fully replaced imported products , Breaking through the plight of being “stuck neck”, China’s imports of high-end oriented silicon steel fell by more than 50%, and the average price decreased by about 60%.

Ten years later, with the support of key basic material technology improvement and industrialization key projects in the “13th Five-Year” National Key R & D Program, after unremitting efforts, China’s oriented silicon steel finally reached a new peak. In 2019, we developed a new 0.18 mm 060 grade oriented silicon steel product with the lowest loss in the world, which is 2 grades higher than the current highest international grade. In the past 10 years, China has launched eight new products of oriented silicon steel in the world, and more than 30 new products have filled the domestic gap, realizing the full coverage of the highest grade of oriented silicon steel in all thickness specifications. The new product is the first to be used in the manufacture of silicon steel laminated core distribution transformers that exceed current national level 1 energy efficiency standards and the world’s highest voltage grade ± 1100kV UHV DC converter transformers.

According to reports, if 060-grade products are used to manufacture transformers with energy efficiency above Class 1, instead of high-energy-consuming transformers in China, annual power savings will be about 90 billion degrees, close to the annual power generation of a Three Gorges power station.

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