HEAVY HEX SYSTEMS

DIN 6914 | DIN 6915 | DIN 6916 | DIN 6917 | DIN 7990
Manufacturer & Exporter – Super Industries India

✅ IMPORTANCE: CRITICAL PAGE

(Mandatory for EPC, infrastructure, steel structure & export buyers)

1. Introduction to HEAVY HEX SYSTEMS

Structural fasteners are load-bearing, safety-critical components used in steel structures, bridges, power plants, towers, and industrial buildings. DIN structural fasteners are designed for controlled preload, high shear strength, and fatigue resistance.

At Super Industries India, we manufacture and export DIN-approved heavy hex structural fasteners that meet international project and inspection requirements.

2. What Makes a Fastener “Structural”?

✔ High tensile strength
✔ Controlled bolt preload
✔ Matched bolt-nut-washer systems
✔ Traceable manufacturing

Structural fasteners are engineered systems, not individual components.

3. DIN 6914 – Structural Hex Bolts

Overview

DIN 6914 bolts are heavy hex bolts used in steel-to-steel connections.

Key Features

✔ Larger head bearing area
✔ High clamp force
✔ Compatible with DIN 6915 nuts

Applications

• Bridges
• Steel buildings
• Transmission towers

4. DIN 6915 – Structural Heavy Hex Nuts

Overview

DIN 6915 nuts are designed to match DIN 6914 bolts.

Properties

✔ High proof load
✔ Controlled hardness

5. DIN 6916 – Structural Washers

Function

Distribute high clamping loads and protect steel surfaces.

Special Feature

✔ Increased thickness vs standard washers

6. DIN 6917 – Direct Tension Indicator (DTI) Washers

⭐ HIGH-VALUE ENGINEERING SECTION

Function

Indicate correct bolt preload via protrusion flattening.

Benefits

✔ Visual preload confirmation
✔ Eliminates torque uncertainty

7. DIN 7990 – Structural Nuts (Alternative Standard)

Used where higher load distribution is required.

8. Bolt Grades & Mechanical Properties

Property Class	Yield (MPa)	Tensile (MPa)
8.8	640	800
10.9	940	1040

9. Materials Used

• Carbon steel
• Alloy steel (Cr-Mo)

10. Surface Treatments

• Black
• Hot dip galvanized
• Mechanical galvanizing

11. Preload & Tightening Methods

✔ Torque tightening
✔ Turn-of-nut method
✔ DTI verification

12. Structural Assembly Best Practices

✔ Use matched fastener sets
✔ Avoid mixing grades
✔ Follow tightening sequence

13. Manufacturing Process

✔ Hot forging
✔ Heat treatment
✔ Thread rolling

14. Quality Control & Testing

• Tensile test
• Proof load test
• Dimensional inspection

15. Inspection & Certification

✔ EN 10204 3.1
✔ Third-party inspection (TPI)

16. Export Packing

• Project-wise crates
• Heat numbers tagged
• Moisture-proof packaging

17. DIN vs ASTM Structural Fasteners

Feature	DIN	ASTM
Usage	Europe / Asia	USA
Head size	Larger	Smaller

18. Industries Served

• Infrastructure
• Power & energy
• Steel fabrication

19. Why Super Industries India?

✔ EPC-ready manufacturing
✔ Structural fastener expertise
✔ Global export experience

20. CTA

📩 Contact us for structural fastener BOQ & project pricing.