Black Oxide 8.8 Grade Hex Socket Bolt

The Black Oxide 8.8 Grade Hex Socket Bolt is a high-strength metric fastener designed for applications requiring reliable torque transmission and durability. Featuring a hexagonal socket (internal wrenching) head, it allows for compact installation in confined spaces while providing superior clamping force.

Key Features:

Material: Made from medium-carbon steel, quenched and tempered to achieve a tensile strength of 800 MPa and a yield strength of 640 MPa (meeting ISO 898-1 or ASTM standards).

Finish: Typically coated with zinc plating (electro-galvanized), black oxide, or other corrosion-resistant treatments.

Head Style: Cylindrical head with an internal hex drive (commonly referred to as a socket head cap screw or Allen bolt).

Thread Type: Fully or partially threaded, with metric coarse/fine pitch options.

Grade Marking: Identified by the "8.8" marking on the head, indicating its property class.

Advantages:

High tensile strength suitable for dynamic or heavy-load applications.

Hex socket design reduces stripping risk compared to external hex heads.

Clean, low-profile appearance ideal for machinery and precision equipment.

Common Applications:

Automotive assemblies

Industrial machinery

Construction equipment

Aerospace components (where specified)

Standards Compliance:

ISO 4762 (Socket head cap screws)

DIN 912 (Metric hex socket bolts)

ASTM A574 (U.S. equivalent for high-strength socket screws)

Additional Notes:

8.8 Grade is comparable to SAE Grade 5 in imperial systems.

Always pair with appropriately graded nuts/washers for optimal performance.