High-end bearing steel, difficult to fill the Chinese manufacturing short board


Core technology to be overcome “High-end bearings depen […]

Core technology to be overcome

“High-end bearings depend on imports. Why can't we make them ourselves?” After investigating five or six provinces including the three provinces of Zhejiang, Zhejiang and Shandong, Wang Dongsheng, executive deputy director of the Shandong Technology Transformation Center of the Chinese Academy of Sciences, found the answer: the biggest problem lies in the materials. "Without good steel, you can never create high-end bearings."

As an indispensable core component in mechanical equipment, the bearing supports the mechanical rotating body, reducing its friction coefficient and ensuring its rotation accuracy. In his view, whether it is an airplane, a car, a high-speed rail, or a high-precision machine tool or instrument, "every part of the rotation needs a bearing."

It is no exaggeration to say that the bearings in the engine have been working in "Purgatory" - it not only has to run at a high speed for tens of thousands of revolutions per minute, but also with various forms of stress extrusion, friction and super high temperature. This puts high demands on the accuracy, performance, life and reliability of the bearing, and the key factor in determining these four points lies in its material.

Regrettably, although China's shaft-making process is close to the world's top level, the material – that is, the high-end bearing steel – is almost entirely imported.

Recently, the Science and Technology Daily reporter interviewed a large state-owned steel group in East China to learn about the latter's embarrassment. As the "Top 100 Chinese Enterprises", this steel group has its own fine steel base, but it can't do high-end steel for bearings. It can only rely on imports. Not long ago, it spent nearly 100 million yuan to import bearing steel.

"PPM" is a unit of oxygen content in steelmaking, meaning parts per million or parts per million. Experts from the Institute of Metal Research of the Chinese Academy of Sciences told the Science and Technology Daily reporter that in general, in the steel industry, 8 PPM steels belong to good steel; 5 PPM steels belong to top steel, which is what high-end bearings need. The research and development, manufacturing and sales of high-end bearing steel are basically monopolized by the world's bearing giants Timken and Sweden's SKF. In the past few years, they established bases in Yantai and Jinan, Shandong, respectively, to purchase low-end materials from China, use their core technology to make high-end bearings, and sell them to the Chinese market at ten times the price.

The addition of rare earths in the steelmaking process will make the original high-quality steel more "strong". But how to add, this is the core secret of the world's bearing giants.

Rare earths are called "industrial vitamins", and rare earth steels are steels containing a certain amount of rare earths. In the 1980s, China had set off a climax of R&D and application of rare earth steel. Scientists generally believed that the addition of rare earth in the steelmaking process was the technical direction to solve the high-end bearing steel. However, after the rare earth was added to the steel, the properties of the steel became When it is good or bad, it is also very easy to block the gate during mass production. Although it has not broken through the technical bottleneck after years of research, it has also caused the rare earth to be cooled by heat in the steel industry.

If a drop of ink is dripped into the same basin of water, what is the appropriate amount of rare earth added to 1 ton of steel? How to add?

The problem is unresolved, and the consequences are: At present, except for a small number of steel grades, steel companies have almost abandoned the application of rare earths in actual production.

However, on the road to research and develop high-end bearing steel, it is not all bad news.

In the previous stage, the material processing simulation research team of the Institute of Metals of the Chinese Academy of Sciences found that the impurity is the main source of non-uniformity of the components through the physical anatomy and calculation of the single-ton 100-ton steel ingot. Based on this, a new mechanism of defect formation in steel is proposed. The industry has caused a lot of repercussions and quickly gained application. Since then, the team has developed the purification preparation technology of commercial rare earth alloys and the special addition technology of rare earths in steel, which has broken through the technical bottleneck of industrial application of rare earth in steel, and realized the process of adding rare earth in steel. Stable performance.

The reporter learned that in recent days, the relevant state ministries and commissions are mulling relevant policies to promote the localization of high-end bearing steel. It can be said that to solve the "card neck" problem of high-end bearing steel, we have taken another step forward. (Technology Daily Jinan May 24th)