DIN 7990 (Hexagon Head Bolt) DIN 555 / ISO 4034 (Hexagon Nut)

Standard Title Hexagon head bolts with hexagon nut for steel structures Hexagon nuts, product grade C / Hexagon regular nuts (Style 1), product grade C
Primary Scope For structural steel bolting (M12 to M36); also suitable for aluminium structures and composite construction General use in machinery for fastening bolts, screws; suitable for most fixing and lighting applications
Product Grade / Tolerance Product Grade C Product Grade C
Mechanical Properties Governed by referenced standards like DIN EN ISO 898-1 Strength class must match or exceed the bolt's (e.g., Class 8 nut for Class 8.8 bolt)
Dimensional Standards Must be used with nuts & washers per standard (e.g., DIN 7989 series) Dimensions and properties for threads from M5 to M64
Materials Not explicitly stated, but typical fastener materials apply (e.g., steel, stainless steel as in commercial offerings) Steel, stainless steel, brass, low carbon steel, bronze, aluminum, titanium
Testing & Delivery Conditions Part of "Technical delivery conditions" covered in DIN Handbook 55 Testing services available per DIN 555 and ISO 4034
Key Application Scenarios • Structural Steel Buildings • Aluminum Structures • Composite Construction • Industrial & Heavy Machinery • General Machinery • Equipment Manufacturing • Fixing and Lighting Applications • Corrosive Environments (using stainless steel nuts)

🔩 Quality and Usage Specifications

DIN7990 Bolt Specifications:

· Size and Assembly: The standard covers hexagon head bolts with sizes ranging from M12 to M36. These bolts are designed to be used with specific hexagon nuts and washers, which are also specified within the standard.
· Mechanical Properties: The technical delivery conditions, including mechanical properties, are defined in the standard. These properties are typically governed by referenced standards such as DIN EN ISO 898-1, which specifies the mechanical properties of fasteners made of carbon steel and alloy steel.
· Quality Assurance: The general "technical delivery conditions" for fasteners like bolts, which include aspects of quality assurance, material specifications, and testing, are covered in comprehensive collections such as DIN Handbook 55.

DIN 555 Nut Specifications:

· International Alignment: The German DIN 555 standard for Product Grade C hexagon nuts is closely aligned with the international standard ISO 4034. This means nuts conforming to ISO 4034 generally satisfy the requirements of DIN555 Nuts.
· Material Variety: These nuts can be manufactured from a range of materials including various types of steel, stainless steel, brass, and aluminum. The choice of material often depends on the required corrosion resistance and strength.
· Strength Matching: A critical quality requirement is that the nut's strength class must be matched appropriately with the bolt's strength class. For instance, a bolt with a property class of 8.8 should be paired with a nut of class 8 or higher to ensure the integrity of the connection.

🏗️ Application Scenarios

DIN 7990 Bolt Applications:
The primary application for DIN 7990 bolts is instructural steel bolting. This makes them a key component in:

· Structural Steel Buildings: Used in the construction of frameworks for industrial buildings, warehouses, and high-rise structures.
· Aluminum Structures and Composite Construction: The standard explicitly mentions that these bolts are also suitable for use in aluminum structures and composite construction, expanding their use beyond traditional steelwork.
· Bridges and Heavy Machinery: Their specified strength and reliability make them suitable for critical, load-bearing connections.

DIN555 Nut Applications:
DIN 555 (ISO 4034) nuts, being general-purpose fasteners, have a wide range of applications:

· General Machinery and Equipment Manufacturing: They are widely used for assembling various types of machinery and equipment.
· Fixing and Lighting Applications: Their simplicity and effectiveness make them common in these areas.
· Applications Requiring Corrosion Resistance: When manufactured from materials like stainless steel, these nuts are preferred in industries with demanding environmental conditions, such as chemical processing, marine applications, or food and beverage industries, due to their high corrosion resistance.

💎 Conclusion

In summary, the DIN 7990 bolt and DIN 555 nut represent a specialized and a general-purpose component in the fastening world, respectively. The DIN 7990 system is engineered for critical, high-strength structural connections, particularly in steel and composite construction. Its quality is ensured through strict dimensional, material, and mechanical property standards. The DIN 555 nut, aligning with ISO 4034, serves as a versatile, general-purpose fastener whose key quality requirement is the proper matching of its strength class with that of the bolt to ensure a safe and reliable assembly.