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The demand for steel for fasteners has increased significantly. In recent years, with the rapid development of the fastener industry in China, the demand for steel for fasteners has also increased significantly. Steel occupies almost 100% of the weight of fasteners. At the same time, taking into account 15% to 20% of the material losses in the production process, one ton of fasteners will require approximately 1.18-1.25 tons of steel. Each year, fasteners consume a considerable amount of steel. considerable. According to relevant information, the demand for fasteners in the cold heading steel market in 2003 reached 3 million tons, and the demand in 2005 increased to 4.5 million tons. In 2006, the national demand reached more than 5.5 million tons.
Steel is the most basic material in fasteners. The fasteners can be made of steel, non-ferrous metals, stainless steel, titanium alloys, or other engineering materials. The processing methods can be hot-working, cutting, but more than 90% pass through cold helium coolant. Compression processing, the products manufactured by this process have high precision, good quality, and high production efficiency. China's fastener industry has maintained a double-digit steady growth for five consecutive years.
Although the proportion of application of non-ferrous metals and composites has increased year by year, the role of steel used for high-strength fasteners cannot be replaced.
Various fasteners are usually made from cold headed steel. From the category classification, the steel used for fasteners is not only carbon steel, but also stainless steel, high-temperature alloy steel, aluminum-magnesium alloy, Monel alloy and so on. Among them, stainless steel and non-ferrous metals account for about 5%-7% of the total amount of consumables. In addition to this, cold-gauge wire is mainly used. The steel grades of cold heading steel wire rods and wire rods are generally low- and medium-carbon high-quality carbon structural steels and low-alloy steels. Low carbon cold heading steel is mainly used for cold heading nuts. The bolts and screws are mainly made of medium-carbon steel (ML35 and SWRCH35K), and they have reached grades 8 and 8 after quenching and tempering.
Cold heading is the use of metal plastic forming at room temperature. Cold heading performance is one of the important properties of cold heading steel. Its performance is mainly characterized by good cold formability; it has as little resistance as possible and high deformability for deformation. Cold heading steel has good cold forming properties. In the machining industry, cold drawing is used in place of hot rolling stock cutting machine. The advantage of this process is that while saving a lot of man-hours, metal consumption can be reduced by 10% to 30%, in line with clean production. Large-scale production of resource-saving companies, and high product dimensional accuracy, good surface finish, and high production efficiency are key advances in advanced machining processes. Therefore, using the cold heading process to manufacture fasteners not only has high efficiency and good quality, but also saves materials and costs.
The development of domestic cold-rolled steel wire rods and wire rods, despite their late start, developed rapidly. Especially after the mid-1980s, high-speed wire rod production lines and wire rod rolling lines were put into production. Cold-rolled steel wire rods and wire rods were put into production. The production provides equipment guarantees. At the end of 2005, the production capacity of cold-drawn wire rods reached 6 million tons/year (about 10-12% of the total wire rods).
The steel plants based on Baosteel, Maanshan Iron and Steel, Xing Steel, Xiang Steel, and Hangzhou Iron and Steel, which have established cooperative relations with the fastener industry, have already formed the industrial cluster for wire rods for cold heading in China. The product varieties are composed of low-carbon, ultra-low-carbon, medium-carbon (tempered and tempered) steels, low-alloy alloy steels, and surface-hardened steels. The specifications range from 5.5 to 42 mm, covering almost all the requirements for fastener steels. .
The principle of stainless steel wire for fasteners is usually selected for bolts, screws, rivets, etc. To ensure safety or generally do not consider the impact of temperature harsh environments or other dangerous conditions. Commonly used materials are carbon steel, low alloy steel and non-ferrous metals. However, in certain situations, fastener materials need to meet severe corrosion or high-strength conditions. Many stainless steels and ultra-high-strength stainless steels have emerged.
Most stainless steel materials can be made into wire or rod for fastener production, including austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and precipitation hardened stainless steel.
Instability in the domestic steel market affects the future development of fasteners
The price of iron ore remains high, and domestic steel prices struggle to survive. This game war can not help but worry about the future of fasteners. Fasteners, also known as 'industrial rice', are a kind of general-purpose general-purpose basic parts that are widely distributed and are closely related to the steel industry at all levels. They not only have a large number of applications but also have a wide range of applications.