Core features of high strength grade 8.8 bolts

1. materials and manufacturing process
Material: low carbon alloy steel or medium carbon steel is used, and alloy elements are added to improve strength and toughness;
Heat treatment: after quenching (improving hardness) and tempering (balancing toughness and strength), a compact structure is formed;
Surface treatment: oxidation blackening treatment is usually carried out to enhance corrosion resistance and prolong service life.
2. mechanical properties
Tensile strength ≥ 800MPa, yield strength ≥ 640mpa, can withstand high load and impact force;
High dimensional accuracy, fine thread processing, convenient installation and stable connection;
Excellent fatigue resistance, stable performance under repeated stress.
Hexagonal head design: external hexagonal structure is convenient for tool installation, providing efficient torque transmission and stable connection;
Half tooth design: the smooth rod body resists shear force, and the threaded section accurately engages the nut to adapt to thermal expansion and cold shrinkage deformation.
3. main application fields
Construction Engineering
Steel structure bridges and steel beam joints of high-rise buildings are connected to ensure the overall bearing stability;
Glass curtain wall aluminum profiles are fixed to resist wind pressure and thermal stress.
Industrial and energy equipment
High load connection of key equipment such as generator set, wind power tower, high-pressure valve, etc.
Transportation
Rail transit equipment.
4. comparison with other bolts
And ordinary hexagon bolt: ordinary bolt (such as grade 4.8) is made of Q235 steel, without heat treatment, and the tensile strength is only 400MPa, which is suitable for low load scenarios;
And higher grade bolts: for example, grade 10.9 bolts are made of alloy steel with a tensile strength of 1000MPa, which are commonly used in extreme load environments.
5. life analysis
Affected by material performance, service environment, load type, installation conditions and other factors, suggestions for life extension:
Optimize the installation process: control the preload to less than 30% of the material strength to avoid over tightening;
Regular maintenance: detect the attenuation of clamping force and retighten or replace it in time;
Matching surface treatment: galvanizing or nickel plating process is preferred in high corrosion environment.