High-Quality High-Strength Flange Bolt
Products Advantages
Unique Structural Advantages: Compared to ordinary high-strength bolts, they have an additional flat flange, which significantly increases the contact area with the fastened surface. This disperses fastening pressure, preventing indentations on soft substrates; furthermore, the flange can replace gaskets, simplifying assembly and improving the sealing and stability of the connection, reducing the risk of loosening in vibration environments.
High-Strength Core Performance: Performance grades are mostly 8.8 and above, with common grades being 8.8, 10.9, and 12.9. Among them, grade 10.9 bolts have a tensile strength of up to 1000MPa and a yield strength of 90% of the tensile strength; some grade 12.9 bolts have a tensile strength of up to 1200MPa, and their wear resistance is 40% higher than that of ordinary bolts. The materials are mostly low-carbon alloy steel or medium-carbon steel, such as 40Cr and 35CrMo. After quenching and tempering heat treatment, plastic deformation or brittle fracture under high loads can be avoided.
Key Specifications and Processes
Mainstream Specifications: Following relevant standards such as GB5787, standard thread sizes cover M5-M20, and lengths can be customized to meet different needs, such as small connections for precision instruments and large fixations for heavy equipment. Some manufacturers also provide non-standard customization services, with the shortest development cycle from drawing design to sample production reduced to 3 days.
Precision Manufacturing and Corrosion Protection Processes: Production involves multiple processes such as cold heading, thread rolling, and heat treatment. Thread accuracy reaches national standard grade 6 or higher, and dimensional tolerances are strictly controlled to ensure assembly accuracy. For corrosion protection, galvanizing, Dacromet coating, and phosphating are commonly used. Salt spray testing has verified its adaptability to humid and slightly corrosive environments. Some products used in marine or chemical settings undergo enhanced corrosion protection processes to extend their service life.
Typical Application Scenarios
Automotive Industry: Suitable for securing core components such as automotive engines and transmissions. These parts must withstand high loads and continuous vibrations from engine operation. Its high strength and anti-loosening properties ensure long-term stable connections and reduce maintenance frequency.
Heavy Machinery and Energy Sector: Used for the assembly of heavy machinery bodies and connection nodes in wind turbine towers, resisting impact loads during equipment operation and outdoor environmental corrosion. It can also be used in generator sets and other equipment to ensure the long-term safe operation of energy equipment.
General Machinery: Suitable for various equipment requiring high-strength sealing connections, such as pipe flange interfaces and the fixing of critical components in precision machine tools. The sealing effect of the flange helps prevent fluid leakage, while its high strength meets the mechanical requirements of equipment operation.
Usage and Selection Precautions
Different strength grades should not be mixed. For example, a 10.9 grade bolt must be paired with a nut of the corresponding strength to avoid connection failure due to strength mismatch.
During installation, use a matching hex wrench to control the preload. The torque method can be used to ensure accurate preload, preventing over-tightening that could damage the bolt or under-tightening that could cause loosening.
Store the product in a rain- and moisture-proof environment to prevent thread corrosion. Verify the product batch and test report to ensure the product meets the strength and corrosion resistance requirements of the application scenario. Unqualified products must not be used.
