In the past 10 years, the overall level of China's fastener manufacturing technology has entered a new stage of modern manufacturing. At present, the process of structural adjustment, transformation and upgrading, from extensive to sophisticated, is also a process of growth and perfection from skills to science. The major reason lies in the concept of the traditional production technology cannot adapt to the needs of the contradiction between continuous innovation and change the quality and efficiency of modern industrial civilization development, it is necessary in the production of fasteners to re-examine, especially before the heat treatment is to confirm the key technology development.

For a long time, three problems, such as short life, poor reliability and heavy structure, have occurred in high strength bolts in our country. Three major problems seriously restricting the development of high-end machinery and equipment and safe service. High strength bolts determine the main connection function of high-end mechanical equipment, which reflects the life, reliability and economic affordability of mechanical equipment, and is the core of high-end machinery manufacturing.

The future is China's manufacturing transformation and upgrading, from the manufacturing big country to the key period of manufacturing power. To this end, the fastener industry has formed a challenge, fastener industry to accelerate the transformation of the mode of economic development has become a top priority.

A large number of high strength bolt fatigue failure analysis results show that the fatigue failure of more than 80% from the surface damage, head junction decarburization, thread processing has obvious small cracks or cutting knife discontinuities and surface corrosion, quenching microstructure is not uniform, because that's where the stress concentration is high.

To accelerate the development of fastener heat treatment without delay, to fully understand the solution of high strength bolt; the three big problems, realize the fasteners of long life and high reliability, the structure weight is a revolution: from the high strength bolt; forming manufacturing technology revolution into Anti fatigue manufacturing; the solution is changed into high strength; the key idea of support bolt revolution for high-end machinery manufacturing sustainable development index; from the final inspection into the process control management revolution; low technology, from the passive to the quality of employees, active high technology revolution; from the cheap labor force, abuse of environment and resources into high value-added, humanization, low emission and green environmental revolution.

Heat treatment is the technique of controlling phase change by heating and cooling, giving the ultimate performance of materials and the ultimate service performance of high strength bolts. It is not only a highly theoretical science, but also a kind of practical technology. Practice is very strong, that is, advanced heat treatment process, with the material and high-strength bolts ever-changing, and constantly innovation, continuous development, progress. As you can see, none of the materials can leave the heat treatment, and none of the high-strength bolts do not rely on heat treatment. It is necessary to point out that heat treatment is one of the only two techniques that give the ultimate properties of materials and the ultimate service performance of high-strength bolts.

Heat treatment of fastener is different from blank making technology and cutting technology. Cold forging billet, billet, billet casting and welding billet can make certain shape and size of blank, very conspicuous. The heat treatment technology is made of fasteners; internal medicine gives high strength bolts of performance, neither hill nor dew. Although heat treatment gives material ultimate performance and gives high strength bolt ultimate service performance, it has not been paid attention to. The core technology of heat treatment of this material and high strength bolt has been excluded from the key technologies of development planning and can not be supported by the key research. It is no exaggeration to say that heat treatment is marginalized and attached, which is the important reason that our fasteners are in the middle and low end manufacturing and competitive disadvantage.

In the process of manufacture of high strength bolts, intelligent, green, lightweight, heat treatment technology plays an important role. The heat treatment process plays a more important role in the manufacture of fasteners. If the heat treatment and cold heading, cold extrusion, cold stamping, and some closely cooperate with the cutting process, the accuracy of fasteners and the rate of finished products will be raised to a higher level.

There are three major problems in China's high strength bolts, such as short life, poor reliability and heavy structure. In addition to the overall system design factors, materials and heat treatment technology is an important factor. Fastener heat treatment should not simply to undertake the processing service, the heat treatment must first pay attention to the material metallurgical quality, including oxygen, inclusions and banded structure, ensure the uniform fine grain structure, determine the relationship between alloy composition and hardenability band and the carbide refinement and ductility.

For the material of important fasteners, a confirmatory test shall be carried out to confirm the inspection documents, such as certificate of conformity, warranty and inspection reports provided by the supplier. Regular inspection of materials is to verify that the properties of the material comply with the relevant material standards and the technical requirements for the thermal treatment of fasteners. The quality of fasteners prior to heat treatment, including pre - treatment and grain size, must be standard for photography. The heat treatment process itself, also includes two aspects, one is the heat treatment technology innovation, including the study of technology, including design, pre heat treatment, heating and cooling of the design process, the two is to optimize the heat treatment process, the best process.

Standard Guide to improve the quality, in recent years, the national fastener Standardization Technical Committee to determine the revision and accelerate key standards, improve the advanced standard, so far, fasteners, bolts and nuts based series of standards about 400 all the updates, to ensure that these standards for the quality of mechanical equipment has played an important role. But standardization exists mainly