ISO 7380-1 Specifications

ISO 7380-1 Key Technical and Specification Summary

1. Scope and Basic Description

   • Product Name: Hexagon socket button head screw.

   • Standard Number: ISO 7380-1:2011.

   • Coverage: Specifies hexagon socket button head screws with threads ranging from M3 to M16 and product grade A.

   • Key Characteristic: The load-bearing strength of these screws is lower than that specified in standard hex socket screw standards (e.g., ISO 898-1). It is crucial to note that they possess reduced loadability.

2. Core Dimensional Specifications

   • Thread Size (d): M3, M4, M5, M6, M8, M10, M12, M16.

   • Key Head Dimensions:

     • Head Diameter (d_k): Provides maximum and minimum dimensions for each thread size, critical for installation space design.

     • Head Height (k): Provides maximum and minimum height for each thread size.

   • Wrench Size (s): Corresponding hex key size, with maximum and minimum values provided.

   • Nominal Length (l): Offers a variety of nominal lengths from 4mm to 100mm, providing minimum and maximum actual dimensions (l_s, l_g) for each length.

   • Other Dimensions: Includes detailed dimensions and tolerances for features like width across flats (e), bearing surface diameter (d_w), and fillet radii (r).

3. Materials and Mechanical Properties

   • Material Options:

     • Steel: Conforms to ISO 898-1, with property classes including 8.8, 10.9, and 12.9/12.9.

     • Stainless Steel: Conforms to ISO 3506-1, with steel grades/property classes including A2-70/A4-70, A2-80/A4-80, etc.

   • Load Capacity:

     • Core Information: Due to their head design, the minimum ultimate tensile load for these screws is lower than the values specified in the general standards ISO 898-1 or ISO 3506-1.

     • Specific Values: The ISO 7380-1 standard specifically provides the minimum ultimate tensile loads for screws with "reduced loadability." For example, an M12 screw of property class 10.9 has a reduced minimum ultimate tensile load of 70,200 N.

   • Surface Treatment: Referenced standards are ISO 4042 (electroplated coatings) and ISO 10683 (non-electrolytically applied zinc flake coatings). Specific requirements should be agreed upon between supplier and purchaser.

4. Important Technical Requirements and Notes

   • Thread Tolerance: Generally 6g, but 5g6g is recommended for property class 12.9/12.9.

   • Product Grade: A.

   • Surface Discontinuities: Limits are specified in ISO 6157-1 (general requirements) and for property class 12.9/12.9 in ISO 6157-3.

   • Acceptance Inspection: Conducted per ISO 3269.

5. Product Designation Examples (Key for Ordering)

   • Steel Screw Example:
     Hexagon socket button head screw ISO 7380-1 - M12 × 40 - 010.9
     (Interpretation: ISO 7380-1 standard, M12 thread, 40mm nominal length, property class 10.9)

   • Stainless Steel Screw Example:
     Hexagon socket button head screw ISO 7380-1 - M12 × 40 - A2-070
     (Interpretation: ISO 7380-1 standard, M12 thread, 40mm nominal length, A2 stainless steel, property class 70)

6. Special Considerations (Crucial for Design Selection)

   • Use Property Class 12.9/12.9 with Caution: The standard specifically advises considering manufacturer capability, service conditions, and tightening methods when using this property class, as the environment can cause stress corrosion cracking.

   • Consequence of "Reduced Loadability": During design, the standard load values from ISO 898-1 or ISO 3506-1 must not be directly referenced. It is essential to use the reduced load values for strength verification.

   • Electroplating and Property Class 12.9: Electroplating should be avoided for screws of property class 12.9/12.9.

Here is a simplified tabular summary of the referenced standards: