Application of Steel in Fasteners

 In 2006, the national demand reached 5.5 million tons. Steel is the most basic material in fasteners Fasteners can be made of steel, non-ferrous metals, stainless steel, titanium alloy or other engineering materials. The processing method can be thermal processing, cutting, but more than 90% With the high precision, good quality and high production efficiency, the fastener industry in China maintains steady double-digit growth for five consecutive years. Although the proportion of non-ferrous metals and composite materials is increasing every year, the role of high-strength steel fasteners can not be replaced. Various fasteners are usually made of cold heading steel. Classification from the species, the fasteners used in addition to carbon steel, there are stainless steel, high temperature alloy steel, aluminum-magnesium alloy, Monel alloy and so on. Stainless steel and non-ferrous metals accounted for about 5% -7% of the total supplies, in addition to the main cold heading wire. Cold heading steel wire, wire rod is generally low, medium carbon high-quality carbon structural steel and low alloy steel. Low-carbon cold heading steel is mainly used for cold heading nuts. Bolts, screws timber mainly in the carbon steel (ML35 and SWRCH35K) based, after quenching and tempering reached 8 and 8 above. 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 reflected in a good cold formability; for the deformation to have the least resistance and possible high deformation capacity. Cold heading steel cold forming due to good performance in the mechanical processing industry instead of hot-rolled material with cold drawing cutting machine processing, this process has the advantage of saving a lot of working hours at the same time, metal consumption can be reduced by 10% -30%, in line with cleaner production , Saving large-scale production of resource-based enterprises, but also high-precision product size, surface finish, high production efficiency, is the focus of the promotion of advanced machining technology. Therefore, the use of cold heading process for the manufacture of fasteners, not only high efficiency, good quality, and the use of materials, low cost. Domestic cold-heading steel wire rod development despite the late start, but the rapid development, especially after the mid-1980s, high-speed wire rod production line, rod rolling production line have put into operation for cold heading steel wire rods The production of equipment provided a guarantee. The end of 2005 cold heading wire production capacity of 6 million tons / year (accounting for about 10-12% of the total wire). With the fastener industry to establish cooperation between Baosteel, Maanshan Iron and Steel, Xing Steel, Xiangtan Iron and Steel, Hangzhou Iron and Steel-based steel mills, has formed a cold forging wire industry group. Variety of products from low carbon, ultra-low carbon, medium carbon (quenched), low alloy steel and surface hardening of steel several major categories of steels, specifications from 5.5 ~ 42mm, almost covering all the needs of fasteners steel . Stainless steel wire used in the selection of the principle Fasteners usually bolts, screws, rivets, etc. In order to ensure safety or generally do not consider the impact of adverse environmental conditions or other dangerous conditions. Common materials are carbon steel, low alloy steel and non-ferrous metals. However, on certain occasions, fastener materials need to meet severe corrosion or high strength conditions, many stainless steel and ultra-high strength stainless steel came into being. Most stainless steel materials can be made into steel wire or bar for the production of fasteners, austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, precipitation hardened stainless steel.