At present, China has the world's largest producer of fasteners, but it has been facing claims due to quality problems were caused among there because the quality of steel, but off lead to the finished fastener case appears quality problems accounted for a large part part of our steel fasteners were yet to meet the strict quality standards of expansion premise.
In recent years, China's fastener enterprises because the product quality is customer claims, in these events, largely because of the use of steel fasteners, but due to customs.
Rough statistics about the current domestic and about 40,000 varieties, millions sizes of fasteners. They use the occasion and the environment is ever-changing. Fastener as the host, the connection member, and bear with the basic properties of the host body, the basic requirements for member functions.
Together to the test in a variety of harsh environments with the host service. High temperature, high pressure, low temperature, vibration, corrosion, overloading, alternating stress, shear torsion various occasions. For example, on some parts of the spacecraft coupled with fasteners must first withstand high temperature, vibration test, but also to withstand sudden changes in temperature after entering orbit, such as the failure to prevent the tightening test at low temperatures, weightlessness conditions. The probability of an accident or disaster fastener failure and damage caused is very high. So the material used in the manufacture of fasteners must be preceded by a strict selection. The commonly used materials are titanium, steel, copper, aluminum, nylon and other metals, non-metallic materials.
The fastener has steel (including alloy steel, low alloy steel, carbon steel) very good ductility and toughness, so it has decided for a variety of processing technology adaptability, but also have good strength, especially after after specific heat treatment to obtain the desired better mechanical properties.
Steel (or wire rod) of steel products it is finished, the factory can not do full inspection, or destructive Moreover, some pilot projects, factory testing only sample testing. For it is a fastener factory production of raw materials, the use of these materials in the manufacture of fastener material is equivalent to one hundred percent full inspection. Now users certain occasions requirements fastener manufacturers to provide "zero defect" fastener products. Therefore, in addition to manufacturers in the production process strict quality control of each process, the factory serious scientific examination of the quality indicators, the choice of good or bad quality of raw materials to the final quality of the finished fastener is decisive.
Many fastener performance quality indicators are provided by the base material. That is a very large number of trade fastener general requirements, due to the application of advanced technologies, such as high-speed cold heading, automatic application of continuous heat treatment production line, but also the raw material for cold heading wire rod hardness, mass fraction of chemical composition, cleaning rod high performance material uniformity requirements are high.
It must first of its profits for Chinese steel fasteners efforts will be necessary
According to the China General Machine Components Industry Association Fastener Materials Association adviser, he said: "Although our country is a fastener producing country, is also the first major steel-producing countries in the world, but steel fasteners development and production development started comparing late.
Cold heading steel varieties and specifications than less, can not meet the needs of the current domestic production of fasteners and exports. Production and market circulation of cold heading steel also borrowed heavily from the JIS Standard G3506, G3507, G4105 and American ASTM many steel grades. "
In this regard, the domestic steel fastener manufacturer in addition to the need to strengthen the innovative research and development, but also the need to ensure quality under the premise of expansion of production capacity.