Hex Bolt Black Oxide Grade 8.8 M8x1.25 (DIN931)

Specification Details: M8-1.25 Grade 8.8 Black Oxide Hex Bolt Set

1. Thread Specification

• Diameter: M8 (8 mm core diameter)
  
• Pitch: 1.25 mm (Metric Coarse Thread)
  
• Thread Direction: Right-Hand Thread (Standard)

2. Dimension Specification (Reference: DIN 931)

• Head Height (k): 5.3 mm
  
• Wrench Size / Across Flats (s): 13 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, the thread length depends on the total length of the bolt (l) as follows:
  
    - For bolt length up to 125 mm: Thread Length = 22 mm
    - For bolt length 126 - 200 mm: Thread Length = 28 mm

3. Mechanical Specification

• Property Class: Grade 8.8 (Manufactured from 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 (Provides basic corrosion resistance for indoor applications or during initial storage).

4. Suitable Applications

• Machinery and Automotive Assembly: Ideal for structural machine joints, industrial equipment, and automotive/motorcycle components that require high strength, tensile endurance, and impact resistance.
  
• Medium to Heavy Industrial Structures: Used for fastening steel structural parts, assemblies, racking systems, or joints that bear standard to heavy loads.
  
• Component and Mold Assembly: Suitable for securing industrial electrical equipment, hand tools, and forming molds that demand tight fastening and higher torque capacity compared to the M6 size.