Hexagon bolts Hexagon nuts Commonly used fastener standards Knowledge
At present, the most commonly used standards in our daily business are as follows:
GB—China National Standard (National Standard) ANSI—American National Standard (American Standard)
DIN—German National Standard (German Standard) ASME—American Society of Mechanical Engineers Standard
JIS—Japanese National Standard (Japanese Standard) BSW—British National Standard
GB—National standard is one of many standards in my country, and there are also industry standards, professional standards and departmental standards. National standards are divided into: GB (mandatory standard), GB/T (recommended standard) and GBn (national internal standard). We usually see GB30, GB5783, etc. are mandatory standards.
In addition to the differences in some basic dimensions such as head width and head thickness, the most important thing for the above standards is the difference in threaded parts. The threads of GB, DIN, JIS, etc. are all in MM (millimeters), collectively referred to as metric threads. Threads like ANSI, ASME, etc. are in inches and are called American standard threads. In addition to metric threads and American threads, there is also a BSW-British standard, whose threads are also in inches, commonly known as Whitworth threads.
The metric thread is in MM (mm), and its cusp angle is 60 degrees. Both American and Imperial threads are measured in inches. The cusp angle of the American thread is also 60 degrees, while the cusp angle of the British thread is 55 degrees. Due to the different units of measurement, the representation methods of various threads are also different. For example, M16-2X60 represents a metric thread. His specific meaning means that the nominal diameter of the screw is 16MM, the pitch is 2MM, and the length is 60MM. Another example: 1/4-20x3/4 means the thread of the British system. His specific meaning is the nominal diameter of the screw. It is 1/4 inch (one inch=25.4MM), there are 20 teeth on one inch, and the length is 3/4 inch. In addition, if you want to indicate American-made screws, UNC and UNF are usually added after the British-made screws to distinguish between American-made coarse threads and American-made fine threads.
In the usual domestic sales business, the standards we most often encounter are GB (National Standard) and DIN (German Standard).
In terms of production products, there are mainly the following standards: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; DIN912; DIN933; At present, GB30 (old national standard) has been replaced by GB5783 (new national standard) in the standard book. GB52 (old national standard) has been replaced by GB6170 (new national standard) in the standard book.
In 1986, our country formulated new standards for standard parts, commonly known as new standards in business, and the most used ones are mainly GB5780, GB5781, GB5782, GB5783, and GB5784. GB5780 is a hexagonal head thick shank half-thread screw, and its precision grade is a C-grade product, which can be replaced by GB5782 (GB5782 is a hexagonal head thick shank full-thread screw, and its accuracy is grade A and B.) GB5781 is a hexagonal head full-thread screw. Tooth screw, precision grade is C grade product. It can be replaced by GB5783 (GB5783 is a hexagonal head full-thread screw, and its precision grades are grade A and grade B). GB5784 is a hexagonal screw with a thin rod and half thread.
The difference between the new standard and the old standard is: M8, M10, M12, M14, and M22 series products differ in width across sides. In addition to the new products of the M22 series, the opposite sides of the heads of the new standard products M8, M10, M12, and M14 are 1MM smaller than the opposite sides of the old standard. They are 13, 16, 18, and 21MM respectively, and for the new products of the M22 series, the opposite side of the new standard is 2MM larger than the old standard, so special attention should be paid. For the thickness of the head, there is a slight difference between the new standard and the old standard, and it can be used universally if the requirements are not very strict.
The growth rate of demand for fasteners in my country is 5%-10%. In 2008, the demand for fasteners was 3.13 million tons, an increase of 9.5% year-on-year. Among them, the automobile industry is the largest user, followed by the maintenance industry market and construction industry, and then electronics industry. Recently, in order to stimulate domestic demand, the state has issued a number of policies to support the manufacturing industry. In the government's 4 trillion yuan investment plan, the focus is on the construction of railways, highways, airports, power grids, and affordable housing infrastructure. The most direct beneficiaries are equipment. Manufacturing industry, which will greatly stimulate the demand for fasteners. In particular, the demand for high-strength fasteners with a specification of 1630mm ≥ 10.9 will increase sharply. In addition, the development of the aviation industry has also played a strong supporting role in the demand for fasteners. For example, Boeing plans to add 3,400 new aircraft in the next 20 years. This data will bring new development and demand opportunities for the fastener industry.
Fasteners are the most widely used basic components in industry today, and are known as "industrial rice". Fasteners are characterized by a wide variety of specifications, different performances and uses, a high degree of standardization, serialization, and generalization, and a wide range of applications, involving many sectors of the national economy. They are widely used in various machinery, equipment, vehicles, ships, Railways, bridges, buildings, structures, tools, instruments, chemicals, instruments and other products. The prosperity of the above-mentioned main application industries is high, and the demand for fasteners is large, which will further stimulate the expansion of the production capacity of fastener enterprises. The technological progress and industrial upgrading of the main application industries will further increase the requirements for the performance and quality of fasteners. Promote the advancement of the technical level of the fastener industry and promote the improvement of the quality of fastener products; the development of new application fields will expand the market demand for fasteners and promote the diversification of fastener products. In recent years, the entire fastener industry in my country has basically maintained a steady and steady growth. Generally speaking, due to the slowdown in global economic growth and the increasing downward pressure on the domestic economy, the growth in downstream demand for fasteners has slowed down, especially The low-end production capacity of domestic fasteners is seriously overcapacitated, but the supply of high-end products is insufficient, and the fastener industry has shifted from high-speed growth to high-quality growth.
Can standard parts be used in that way? In fact, standard parts are a type of mechanical parts that are used for fastening connections and are widely used. All kinds of fasteners can be seen on various machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, meters and supplies. It is characterized by a wide variety, different performances and uses, and the degree of standardization, serialization, and generalization is also extremely high. Therefore, some people also refer to a class of fasteners with existing national standards as standard fasteners, or simply as standard parts. Fasteners are the most widely used basic mechanical parts. With my country's accession to the WTO in 2001, it has entered the ranks of international trade powers. Construction fastener T-bolt
With the development and progress, the quality of its industrial demand is getting higher and higher, so the requirements for fasteners are also increasing. High-strength fasteners can meet everyone's needs. At present, the development prospects of high-strength fasteners are good. However, there are still some problems with domestic high-strength fasteners. According to our understanding, there are mainly the following major problems.
At present, the most commonly used standards in our daily business are as follows:
High-strength bolts are high-strength bolts and belong to a standard part. In general, high-strength bolts can withstand a larger load than ordinary bolts of the same specification.