Fastener companies in China have the technology to develop high-strength bolts

Recently, BMW decided to recall a total of 232,000 related vehicles because the fixing bolts on the engine casings of some of its models may loosen or even break. In recent years, there have been many cases of recalls due to bolt problems, and bolts have become the smallest part of the car but cannot be ignored. In the process of interviews in the past, some parts companies reported to reporters that few domestic fastener companies have the ability to produce high-strength bolts, and many high-strength bolts used in some key positions such as engines and chassis rely on imports. So, what is the strength of domestic bolt manufacturers? Do high-strength bolts have to rely on imports?

Some high-strength bolts can be purchased domestically

Generally speaking, bolts are divided into more than 10 grades from 3.6 to 12.9 according to the nominal tensile strength and yield ratio, and the requirements for use in different fields are also quite different. Chen Kun, director of the marketing department of the Fastener Branch of Fuao Auto Parts Co., Ltd., told reporters: “The car needs to use thousands of bolts, most of which are 8.8 and above bolts, including 10.9 and 12.9 bolts. Only then can it be called a high-strength bolt.”

Chen Kun took engine bolts as an example. The bolts for fixing the peripheral parts of the engine have relatively low technological requirements, and ordinary bolts can meet the requirements. The high-strength bolts we often say are mainly related to the internal strengths of the engine. For example, the flywheel bolts and connecting rod bolts must be grade 10.9, while the engine cylinder head bolts must reach grade 12.9.

The reporter interviewed a number of engine and automobile chassis related companies and asked about the purchase of high-strength bolts. These companies all said that high-strength bolts do not completely rely on imports, and that self-owned brand companies are more willing to purchase domestic high-strength bolts, and joint ventures are gradually localizing various bolt products to save costs.

Chen Kun said that Fuao Fasteners has invested heavily in the development of a variety of 10.9-grade high-strength bolts for the Volkswagen EA211 engine. The matching standards are consistent with those in Germany, and there are two types that have been mass-produced. Liu Kai, deputy general manager of Jiangxi Isuzu Engine Co., Ltd., said that the high-strength bolts of Isuzu diesel engines have been purchased domestically, and the procurement standards are consistent with Isuzu Japan’s procurement standards. Sun Jingyao, deputy director of the Quality Control Department of Qingte Group Co., Ltd., told reporters: “Not all high-strength bolts used in Qingte axles are imported, and some domestic fastener companies can also meet our process needs.”

The strength of domestic enterprises is still lacking

“The manufacturing process of high-strength bolts is highly demanding, especially for high-strength bolts for vehicles. Any defect will seriously affect driving safety.” Chen Yuanzhi, director of the International Department of China Association of Automobile Manufacturers, told reporters.

Chen Yuanzhi said that some fastener companies in my country have the technology to develop high-strength bolts and can manufacture high-strength bolt samples, but it is difficult to ensure the quality of each product in mass production. The main reason is that the product consistency cannot meet the batch requirements. , In addition, the supply of domestic advanced alloy materials is insufficient or there is no better material to supply. Therefore, some high-strength bolts still rely on imports.

It is understood that domestic general fastener companies can supply 8.8-grade bolts, and there are not many companies that can mass-produce 10.9-grade bolts, but not many companies can produce 12.9-grade bolts. Chen Kun said that, in fact, there are only about 5 fastener companies in China that have the ability to produce high-strength bolts and can do well and are recognized by the industry. It is worth noting that the only few enterprises also include joint ventures and wholly foreign-owned enterprises.

From the analysis point of view, domestic enterprises have insufficient motivation to develop high-strength bolts.

Chen Kun said that compared with ordinary bolts, the profit of high-strength bolts is not obvious. Coupled with the large investment in the early stage, some small enterprises may not make ends meet in R&D and production of high-strength bolts; each automobile company has different requirements for high-strength bolts. This makes the matching of such products more difficult and the cycle becomes longer; joint venture brands are very cautious about the localization of high-strength bolts, and localization will only select companies within their supporting systems, and domestic fastener companies rarely have supporting opportunities.

The production link cannot escape the import

Although some high-strength bolts can be purchased domestically, it seems that domestic fastener companies have a certain production strength, but in fact, every production link of high-strength bolts is difficult to be separated from imports. Chen Kun said that the difficulty of producing high-strength bolts lies in the following aspects: the cold heading forming process has high requirements on product tolerances, which requires more sophisticated production equipment, and these cold heading equipment must be imported from abroad or from Taiwan; The uniformity of product hardness depends on the heat treatment process, and high-end heat treatment furnaces also need to be imported; product surface treatment is also the key, and the required solutions are also imported from overseas.

The huge capital investment in equipment procurement determines that some small fastener companies cannot join the production of high-strength bolts. Chen Kun said that Fuao Fasteners has spent two years developing high-strength bolts for the Volkswagen EA211 engine, investing tens of millions of yuan to install general-purpose equipment, heat treatment furnaces for car fasteners, and a series of testing equipment. The product must also pass the testing and certification of relevant foreign institutions.

The raw materials of high-strength bolts are also inseparable from imports. It is understood that my country’s automotive fastener materials are mainly produced by Baosteel Group, and many domestic vehicle enterprises regard Baosteel as the designated manufacturer of steel for special standard parts. A small number of high-strength bolt raw materials with special needs need to be imported from Japan and South Korea. “Such a huge investment is because we are targeting the demand for localization or domestic procurement of high-strength bolts of vehicle companies. Although there will not be a surge in demand in the short term, this demand will exist for a long time.” Chen Kun said.

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