National Standards For High-strength Bolts in Different Countries

According to Chinese national standards, the standard for high-strength bolts is GB/T 3632-2018 "Bolts, Screws, Studs, and Nuts for High Strength Fasteners". This standard specifies the requirements for the classification, size, material, mechanical properties, surface treatment, etc. of high-strength bolts.

According to this standard, high-strength bolts are divided into two grades: grade 10.9 and grade 12.9. Among them, the tensile strength of the 10.9 grade bolt is 1000MPa, and the yield strength is 900MPa; The tensile strength of grade 12.9 bolts is 1200MPa, and the yield strength is 1080MPa. These grades of high-strength bolts are mainly used in engineering structures that require high connection requirements and bear large loads, such as bridges, high-rise buildings, automobile manufacturing, and other fields.
In addition, the standard also specifies the size range, material requirements, and mechanical performance requirements for high-strength bolts. The size of bolts includes thread diameter, thread length, bolt length, etc. Choose the appropriate size according to specific usage requirements. The material for high-strength bolts is usually alloy steel to ensure their strength and corrosion resistance. In terms of mechanical performance, the standard requires high-strength bolts to have certain performance indicators in terms of tension, yield, and elongation.
Following national standards for the design, manufacturing, and use of high-strength bolts can ensure the reliability and safety of bolt connections. In engineering practice, high-strength bolts that meet specific engineering requirements and standard specifications should be selected for use to ensure the stability and safety of the engineering structure.
In addition to the national standard GB/T 3632-2018, "Bolts, Screws, Studs and Nuts for High Strength Fasteners", there are also some universal standards and specifications internationally, such as ISO (International Organization for Standardization) and ASTM (American Society for Testing and Materials).
In ISO standards, the relevant standards for high-strength bolts include ISO 898-1 and ISO 898-2. ISO 898-1 specifies the mechanical performance requirements for high-strength bolts, including tensile strength, yield strength, elongation, etc. ISO 898-2 specifies requirements for the dimensions and allowable tolerances of high-strength bolts.
In ASTM standards, the relevant standards for high-strength bolts include ASTM A325 and ASTM A490. These standards mainly apply to structural bolts, with ASTM A325 for carbon steel materials and ASTM A490 for alloy steel materials. These standards specify requirements for the chemical composition, mechanical properties, dimensions, allowable tolerances, and other aspects of high-strength bolts.
It should be noted that different countries and regions may have different standards and specifications. Therefore, in practical applications, the appropriate high-strength bolt standard should be selected according to the requirements of the country or region's standards.
The existence of standards and specifications for high-strength bolts helps to ensure the quality and reliability of bolt connections and improve the safety of engineering structures. When using high-strength bolts, they should be designed, manufactured, and installed strictly in accordance with relevant standards to ensure the firmness and durability of the bolt connection.