DIN933 DIN931 Grade 10.9 12.9 Hex Bolt

DIN933 DIN931 Grade 10.9 12.9 Hex Bolt's DIN933 and DIN931 are specifications for hexagonal bolts. And these hex bolts are of Grade 10.9 and Grade 12.9, which indicate high tensile strength and are designed to withstand significant mechanical loads.

1. Standards & Specifications

DIN 933: Fully threaded hexagon head bolt (similar to ISO 4017).

DIN 931: Partially threaded hexagon head bolt (similar to ISO 4014).

Grades:

10.9: High tensile (Yield strength ≥ 900 MPa, Tensile strength ≥ 1000 MPa).

12.9: Ultra-high tensile (Yield strength ≥ 1080 MPa, Tensile strength ≥ 1200 MPa).

Finish: Black Oxide (corrosion-resistant, aesthetic, and improves friction properties).

2. Key Features

Material: Typically carbon steel (e.g., 35CrMo, 45Cr) or alloy steel, heat-treated for strength.

Thread Type: Metric coarse or fine thread (e.g., M6, M8, M10, etc.).

Head Style: Hexagonal (6-sided) for standard wrench/spanner tightening.

Black Oxide Benefits:

Mild corrosion resistance (not for harsh environments unless coated further).

Reduces light reflection (useful in military/optical applications).

Minimal dimensional change vs. electroplating.

3. Applications

Automotive: Engine components, chassis, and high-stress assemblies.

Machinery: Heavy-duty equipment, presses, and industrial tools.

Construction: Structural connections requiring high clamp force.

Aerospace/Defense: Non-critical black-finished fasteners (check specific standards).