Analysis Of Material And Standards For Grade 8.8 Bolts

There is no specific material specification for Grade 8.8 bolts; only the allowable range of chemical composition is defined. Any material meeting the requirements within this range can be used for manufacturing Grade 8.8 high-strength bolts. However, many professionals still regard the standards for Grade 8.8 bolts as an important reference for material selection.

To meet the performance requirements of Grade 8.8 bolts for different applications, the material must undergo special heat treatment (quenching + tempering) to achieve the following characteristics:

The nominal tensile strength of the bolt material reaches 800MPa;

The yield ratio (yield strength/tensile strength) of the bolt material is 0.8;

The nominal yield strength of the bolt material reaches 800MPa × 0.8 = 640MPa;

For material selection of Grade 8.8 hex head bolts: 1035ACR (for M10 and below), 1040ACR (for M12 and above), CH38F, 1045ACR, 1039, 10B21, 10B33, 10B38, etc., are applicable;

For material selection of Grade 8.8 hex socket cap screws: CH38F, 1039, 10B21 (for M10-M12), 10B33 (for M14), 10B38 (for M12-M24), 1035ACR (for M10 and below), 1040ACR (for M12 and above), etc., are applicable;

Material selection of wire rod for carbon steel fasteners:

Grade 4.8 hex head bolts: 1008K, 1010, 1015K, etc.;

Grade 6.8 hex head bolts: 1032, 1035, 1040, CH38F, 1039, etc.;

Grade 10.9 hex head bolts: 1045ACR, 10B38, etc.;

Nuts of Grade 8 and above: 1015 (for M<16), CH38F (for M≥16), etc.;

Grade 10 nuts: CH38F, 1039, 10B21, 10B33, etc.;

Grade 12 nuts: 1039, 10B21, 10B33, 10B38, etc.;

Carriage bolts: 1008, 1010, 1015, etc.;

Hex flange bolts: CH38F, 1039, 10B21, 10B33, 10B38, etc.;

Hex lag screws: 1008K, 1010, etc.;

Self-tapping screws, drywall screws, drill tail screws, chipboard screws: 1018, 1022, CH22A, etc.

A thorough understanding of the material and performance requirements of Grade 8.8 bolts can help you better select suitable materials to meet your engineering needs.