When structural integrity under extreme pressure is non-negotiable, the M30 high-strength hex bolt manufactured to DIN 931 standards emerges as the premier solution. Engineered from grade 10.9 high-tensile steel, this fastener delivers unparalleled performance for critical connections across multiple industries.
M30 Hex Bolt (DIN 931): Definition and Key Characteristics
The M30 hex bolt, conforming to German industrial standard DIN 931, represents a benchmark in fastener technology. The "M30" designation indicates a 30mm thread diameter, while the DIN 931 specification governs dimensional parameters, material properties, and manufacturing tolerances.
Distinctive Features:
- Hexagonal Head: Designed for optimal torque transmission using standard wrenches or socket tools.
- Partial Threading: Features an unthreaded shank portion that enhances shear resistance in structural applications.
- Grade 10.9 High-Tensile Steel: Delivers exceptional mechanical properties with a minimum tensile strength of 1,000 MPa and yield strength of 900 MPa.
The Advantage of Grade 10.9 High-Strength Steel
Grade 10.9 fasteners offer three critical performance advantages:
- Superior Tensile Strength: Withstands extreme axial loads without fracture.
- High Yield Strength: Maintains structural integrity under significant stress before plastic deformation occurs.
- Exceptional Hardness: Provides resistance to wear and deformation in demanding environments.
Technical Specifications: DIN 931 Standard Parameters
Key dimensional and technical specifications include:
- Thread Diameter (M): 30mm
- Pitch (P): 3.5mm (standard coarse thread)
- Head Width (S): 46mm max
- Head Height (k): 19.12mm max
- Material: High-tensile steel (grade 10.9)
- Surface Treatment: Typically plain finish, with optional coatings including zinc plating or Dacromet available
Industrial Applications
The M30 high-strength bolt serves critical functions across multiple sectors:
- Civil Engineering: Structural steel connections, bridge construction
- Heavy Machinery: Equipment assembly and component fixation
- Automotive Systems: Engine and chassis component fastening
- Petrochemical Infrastructure: Pipeline and storage tank connections
- Transportation Networks: Railway track and rolling stock assemblies
Selection Criteria for Optimal Performance
When specifying M30 hex bolts, consider these critical factors:
- Verify material certification for grade 10.9 compliance
- Confirm dimensional compatibility with mating components
- Select appropriate surface treatment for environmental conditions
- Ensure supplier quality certifications (ISO 9001, etc.)
Installation Best Practices
Proper installation ensures long-term reliability:
- Clean mating surfaces thoroughly before assembly
- Apply appropriate thread lubricant to achieve proper clamp load
- Use calibrated torque wrenches to achieve specified preload
- Implement regular maintenance inspections
Performance Considerations
Advantages:
- Exceptional load-bearing capacity
- Standardized dimensions for interchangeability
- Broad industrial applicability
Limitations:
- Higher material costs compared to lower-grade fasteners
- Requires precise torque application
- May require corrosion protection in harsh environments
Technical FAQs
Q: How is thread length determined for M30 bolts?
A: Minimum thread length varies with overall bolt length per DIN 931 specifications.
Q: What torque values apply to M30 grade 10.9 bolts?
A: Torque specifications depend on surface treatment and lubrication - consult engineering references.
Q: What methods prevent bolt loosening?
A: Locknuts, spring washers, or thread-locking compounds provide vibration resistance.
