Hex Bolt Black Oxide Grade 8.8 M12-1.75 (DIN931)

Specification Details: M12-1.75 Grade 8.8 Black Oxide Hex Bolt Set (English)

1. Thread Specification

• Diameter: M12 (12 mm core diameter)
• Pitch: 1.75 mm (Metric Coarse Thread)
• Thread Direction: Right-Hand Thread (Standard)

2. Dimension Specification (Reference: DIN 931)

• Head Height (k): 7.5 mm
• Wrench Size / Across Flats (s): 19 mm (Used for both bolt head and hex nut)
• Bolt Type: Hexagon Head Partial Thread (DIN 931 Standard)
• Thread Length (b): Based on the DIN 931 standard:

          - For bolt length up to 125 mm: Thread Length = 30 mm
          - For bolt length 126 - 200 mm: Thread Length = 36 mm
          - For bolt length over 200 mm: Thread Length = 49 mm

3. Mechanical Specification

• Property Class: Grade 8.8 (Medium Carbon Steel, Quenched and Tempered)
  
• Tensile Strength: 800 N/mm² (800 MPa)
  
• Yield Strength: 640 N/mm² (640 MPa)
  
• Surface Finish: Black Oxide Finish with a light anti-rust oil coating.

4. Suitable Applications

• Heavy Machinery and Commercial Vehicles: Ideal for large machinery frameworks, truck suspension parts, tractors, and high-vibration/high-impact equipment.
  
• Construction and Industrial Structures: Used for fastening heavy structural steel, warehouse roof trusses, bridge components, and extreme heavy-duty racking systems.
  
• Heavy Component and Large Mold Assembly: Suitable for securing machine beds, metal stamping molds, or applications requiring exceptional tightening torque and high safety standards.