Hexagon Socket Screws

Hexagonal socket screws are fasteners with hexagonal grooves on the head that require special wrenches for installation. They have high torque, are not easy to slip teeth, and can be hidden for installation. They are one of the most commonly used fasteners in industry and daily life.

Mainstream standards in various countries/regions

-International standards (ISO): ISO 4762 (cylindrical head), ISO 898-1 (mechanical properties), globally recognized.
-China (GB): GB/T 70.1 (Cylindrical Head, equivalent to ISO 4762), GB/T 3098.1 (Performance Grades).
-Germany (DIN): DIN 912 (cylindrical head, equivalent to ISO 4762), mainstream in Europe.
-USA (ANSI/ASME): ASME B18.3 (American Hexagon), ASTM F568M (Metric High Strength).  
-Japan (JIS): JIS B1176 (cylindrical head), compatible with Japanese equipment.  

Common materials and strength grades

Carbon steel (most commonly used)
-Grade 4.8 : Low carbon steel, tensile strength ≥ 400MPa, light load, indoor fixed (shelves, furniture).  
-Grade 8.8: Medium carbon steel (45 #, 35K), tensile strength ≥ 800MPa, universal mechanical and equipment structure.
-Grade 10.9/12.9: Alloy steel (40Cr, SCM435), tensile strength ≥ 1000/1200MPa, heavy-duty and vibration scenarios (engine, mold).
Stainless steel (corrosion-resistant)
-304 (A2-70): Tensile strength ≥ 700MPa, suitable for food, medical, and humid environments.
-316 (A4-80): Tensile strength ≥ 800MPa, resistant to seawater/acid alkali, marine, chemical, outdoor.  
Other
Titanium alloy (TC4): lightweight and high-strength, suitable for aviation, racing, and high-end medical applications.
Aluminum alloy: lightweight, rust proof, electronic, instrument, lightweight structure.