From the development of the whole manufacturing industry, fasteners are known as "industrial rice". Fasteners usually account for only a small part of the whole product structure, but as an organic part of the product, they play an important role. From the application of Fastener standard parts in the world, the industries mainly include electronic industry, maintenance and construction industry and automobile industry, which are the three major users of fasteners. For example, there are many kinds of automotive fasteners, which are mainly divided into four categories, including standard fasteners, non-standard fasteners, standard mechanical components and non-standard mechanical components; Among them, the quality of non-standard fasteners is required to be high. Among the non-standard fasteners, engine connecting rod bolts, flywheel bolts, wheel bolts, suspension bolts and so on, because of their high quality and good stability requirements, China can not meet the requirements of localization, and a small part of them rely on imports.
Due to the lack of attention to fasteners in the automotive industry, the development of automotive fasteners lags far behind the development of the automotive industry. Fasteners account for a small proportion in the finished automobile products, but the damage to the whole vehicle is great. The reasons for the fracture of fasteners can be analyzed from the following three aspects: the material strength of fasteners is not enough, and the fracture occurs under the action of external load; Because the material used in the fastener is unreasonable in the process of heat treatment, there are surface cracks and other defects; Due to the fatigue fracture of fasteners under long-term external load.
In order to produce high quality fastener standard products, in the process of selecting the steel used for fasteners, it is necessary to strictly control the chemical composition of the steel used, reduce the content of harmful elements s, P and O in the steel, and reduce the influence of oxide and sulfide inclusions on the cracking of fasteners in the production process; In the process of fastener heat treatment, the temperature, time and atmosphere in the heating furnace should be strictly controlled to reduce the oxidation and decarburization of fastener surface. Therefore, after the completion of mass production, the final sorting and testing must be carried out, such as manual selection, eddy current sorting, optical sensor size and profile sorting, to sort out the defective products with obvious defects, such as surface cracks, surface decarburization and unqualified products, so as to meet the requirements of customers. Defect free fasteners are the key to ensure the smooth operation of the assembly line, the safe driving of vehicles and the good reputation of manufacturers.
Although China's production is huge, but the fastener started late compared with foreign countries. Many enterprises have low investment in science and technology, weak scientific and technological development force, backward technology, long delivery cycle, lagging behind the improvement of quality and quantity, weak awareness of innovation strategy, insufficient independent innovation ability and imperfect innovation system construction. In recent years, a large number of foreign fastener enterprises have poured into China, while China's fastener enterprises have both challenges and opportunities. Domestic fastener enterprises need to build brand, improve quality, ensure a higher qualified rate of parts, and strive for the goal of zero defects.
Although there is still a significant gap between domestic fastener enterprises and foreign advanced level, China's Fastener standard industry has a certain industrial foundation and advantages after long-term development. Small scale, weak technical force, relying on inferior raw materials and shoddy low price competition, fastener enterprises without brand will be eliminated in transformation and innovation.
From the perspective of the world structure, China is a big fastener producer. The world cannot do without China's fastener manufacturing. China also needs the world market. The industry has broad development space in both horizontal scale development and vertical technology upgrading. The industry should strive to become a strong fastener producer.
