Introduction
The ISO 4017:2022 standard specifies the characteristics of hexagon head screws with threads from M1.6 to M64, of product grades A and B. This standard is crucial in mechanical engineering and manufacturing industries, ensuring uniformity and reliability in fastening components. It defines precise dimensions, tolerances, and mechanical properties for these screws, which are widely used in assembly, construction, and machinery applications.
Hexagon head screws, also known as hex bolts, provide robust fastening solutions due to their six-sided head design, allowing for high torque application. The distinction between grades A and B lies in their precision: Grade A offers higher accuracy for smaller sizes and shorter lengths, while Grade B is suitable for larger or longer screws where slightly looser tolerances are acceptable. This standard replaces previous versions, incorporating updates for improved material compatibility and manufacturing practices.
In metalworking and assembly lines, adherence to ISO 4017 ensures interchangeability and safety. For instance, in automotive and aerospace sectors, these screws must withstand specific loads without failure. The standard covers steel and stainless steel materials, with references to mechanical property classes like 8.8 or A2-70. It also addresses surface treatments to enhance corrosion resistance.
This article provides a comprehensive guide to the standard’s specifications, including dimensional tables, material requirements, and practical applications. Engineers and procurement specialists can use this information to select appropriate screws for their projects, ensuring compliance with international norms. The dimensional data is presented in millimeters, covering key parameters such as pitch, head height, and width across flats.
Understanding ISO 4017 is essential for quality control, as deviations can lead to assembly failures or safety hazards. The standard’s scope includes full-threaded and partially threaded screws, with tolerances designed to minimize production costs while maintaining performance. For specialized applications, such as high-temperature environments, additional agreements may be needed.
Overall, ISO 4017 promotes global trade by standardizing fastener specifications, reducing errors in supply chains. This guide expands on the provided data, offering insights into implementation and best practices.
ISO 4017:2022 Standard Overview
Published in 2022 by the International Organization for Standardization, ISO 4017 updates the 2014 edition with refinements in tolerances and material references. It applies to hexagon head screws made from carbon steel, alloy steel, or stainless steel, with metric coarse pitch threads. The standard excludes fine pitch threads, which are covered by other ISO documents.
The scope includes screws with diameters from M1.6 to M64, suitable for general engineering purposes. Key contents cover dimensions, mechanical properties, tolerances, surface finishes, and acceptance criteria. Product grade A is for precise applications where d ≤ 24 mm and l ≤ 10d or 150 mm (whichever is smaller), while grade B applies to larger sizes or lengths.
This overview highlights the standard’s role in ensuring product reliability. It references ISO 898-1 for steel mechanical properties and ISO 3506-1 for stainless steel. Tolerances are per ISO 4759-1, with 6g thread tolerance. Surface treatments include electroplating (ISO 4042), non-electrolytic zinc flake coatings (ISO 10683), and hot-dip galvanizing (ISO 10684).
For stainless steel, surfaces are clean and bright, with optional passivation per ISO 16048. Acceptance and packaging follow ISO 3269, while surface discontinuities are limited by ISO 6157-1 or -3 for high-strength classes. The standard allows agreements for custom requirements, enhancing flexibility.
In practice, this standard influences design specifications in industries like machinery manufacturing and construction. By providing clear guidelines, it reduces variability in production, aiding in cost-effective sourcing. Engineers should note that for diameters over M39, properties are by agreement.
Dimensions and Specifications
The core of ISO 4017:2022 lies in its detailed dimensional requirements for hexagon head screws. These specifications ensure compatibility and performance across various applications. Dimensions are in millimeters, covering thread pitch (P), incomplete thread length (a), head chamfer (c), major diameter allowance (da), width across corners (e), head height (k), and width across flats (s).
Grades A and B differ in tolerance levels for certain dimensions, such as dw (effective contact diameter) and e (width across corners). For example, smaller screws (up to M16) often fall under grade A for precision, while larger ones use grade B. The standard also specifies minimum radii (r) and washer face heights (k1).
Below is a comprehensive table of dimensions for thread sizes from M1.6 to M64. Data has been verified against standard values to ensure accuracy, with parentheses indicating non-preferred sizes.
| Thread d | M1.6 | M2 | M2.5 | M3 | (M3.5) | M4 | M5 | M6 | (M7) | M8 | M10 | M12 | (M14) | M16 | (M18) | M20 | (M22) | M24 | (M27) | M30 | (M33) | M36 | (M39) | M42 | (M45) | M48 | (M52) | M56 | (M60) | M64 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| P (hauteur) | 0.35 | 0.4 | 0.45 | 0.5 | 0.6 | 0.7 | 0.8 | 1 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | 2.5 | 2.5 | 3 | 3 | 3.5 | 3.5 | 4 | 4 | 4.5 | 4.5 | 5 | 5 | 5.5 | 5.5 | 6 |
| un maximum | 1.05 | 1.2 | 1.35 | 1.5 | 1.8 | 2.1 | 2.4 | 3 | 3 | 3.75 | 4.5 | 5.25 | 6 | 6 | 7.5 | 7.5 | 7.5 | 9 | 9 | 10.5 | 10.5 | 12 | 12 | 13.5 | 13.5 | 15 | 15 | 16.5 | 16.5 | 18 |
| a min | 0.35 | 0.4 | 0.45 | 0.5 | 0.6 | 0.7 | 0.8 | 1 | 1 | 1.25 | 1.5 | 1.75 | 2 | 2 | 2.5 | 2.5 | 2.5 | 3 | 3 | 3.5 | 3.5 | 4 | 4 | 4.5 | 4.5 | 5 | 5 | 5.5 | 5.5 | 6 |
| c max | 0.25 | 0.25 | 0.25 | 0.4 | 0.4 | 0.4 | 0.5 | 0.5 | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| c min | 0.1 | 0.1 | 0.1 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 |
| da max | 2 | 2.6 | 3.1 | 3.6 | 4.1 | 4.7 | 5.7 | 6.8 | 7.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | 20.2 | 22.4 | 24.4 | 26.4 | 30.4 | 33.4 | 36.4 | 39.4 | 42.4 | 45.6 | 48.6 | 52.6 | 56.6 | 63 | 67 | 71 |
| dw A min | 2.54 | 3.34 | 4.34 | 4.84 | 5.34 | 6.2 | 7.2 | 8.88 | 9.63 | 11.63 | 14.63 | 16.63 | 19.64 | 22.49 | 25.34 | 28.19 | 31.71 | 33.61 | / | |||||||||||
| dw B min | 2.42 | 3.22 | 4.22 | 4.72 | 5.22 | 6.06 | 7.06 | 8.74 | 9.47 | 11.47 | 14.47 | 16.47 | 19.15 | 22 | 24.85 | 27.7 | 31.35 | 33.25 | 38 | 42.75 | 46.55 | 51.11 | 55.86 | 59.95 | 64.7 | 69.45 | 74.2 | 78.66 | 83.41 | 88.16 |
| e A min | 3.41 | 4.32 | 5.45 | 6.01 | 6.58 | 7.66 | 8.79 | 11.05 | 12.12 | 14.38 | 17.77 | 20.03 | 23.36 | 26.75 | 30.14 | 33.53 | 37.72 | 39.98 | / | |||||||||||
| e B min | 3.28 | 4.18 | 5.31 | 5.88 | 6.44 | 7.5 | 8.63 | 10.89 | 11.94 | 14.2 | 17.59 | 19.85 | 22.78 | 26.17 | 29.56 | 32.95 | 37.29 | 39.55 | 45.2 | 50.85 | 55.37 | 60.79 | 66.44 | 71.3 | 76.95 | 82.6 | 88.25 | 93.56 | 99.21 | 104.86 |
| k nominal | 1.1 | 1.4 | 1.7 | 2 | 2.4 | 2.8 | 3.5 | 4 | 4.8 | 5.3 | 6.4 | 7.5 | 8.8 | 10 | 11.5 | 12.5 | 14 | 15 | 17 | 18.7 | 21 | 22.5 | 25 | 26 | 28 | 30 | 33 | 35 | 38 | 40 |
| k A max | 1.225 | 1.525 | 1.825 | 2.125 | 2.525 | 2.925 | 3.65 | 4.15 | 4.95 | 5.45 | 6.58 | 7.68 | 8.98 | 10.18 | 11.715 | 12.715 | 14.215 | 15.215 | / | |||||||||||
| k A min | 0.975 | 1.275 | 1.575 | 1.875 | 2.275 | 2.675 | 3.35 | 3.85 | 4.65 | 5.15 | 6.22 | 7.32 | 8.62 | 9.82 | 11.285 | 12.285 | 13.785 | 14.785 | / | |||||||||||
| k B max | 1.3 | 1.6 | 1.9 | 2.2 | 2.6 | 3 | 3.74 | 4.24 | 5.04 | 5.54 | 6.69 | 7.79 | 9.09 | 10.29 | 11.85 | 12.85 | 14.35 | 15.35 | 17.35 | 19.12 | 21.42 | 22.92 | 25.42 | 26.42 | 28.42 | 30.42 | 33.5 | 35.5 | 38.5 | 40.5 |
| k B min | 0.9 | 1.2 | 1.5 | 1.8 | 2.2 | 2.6 | 3.26 | 3.76 | 4.56 | 5.06 | 6.11 | 7.21 | 8.51 | 9.71 | 11.15 | 12.15 | 13.65 | 14.65 | 16.65 | 18.28 | 20.58 | 22.08 | 24.58 | 25.58 | 27.58 | 29.58 | 32.5 | 34.5 | 37.5 | 39.5 |
| k1 A min | 0.68 | 0.89 | 1.1 | 1.31 | 1.59 | 1.87 | 2.35 | 2.7 | 3.26 | 3.61 | 4.35 | 5.12 | 6.03 | 6.87 | 7.9 | 8.6 | 9.65 | 10.35 | / | |||||||||||
| k1 B min | 0.63 | 0.84 | 1.05 | 1.26 | 1.54 | 1.82 | 2.28 | 2.63 | 3.19 | 3.54 | 4.28 | 5.05 | 5.96 | 6.8 | 7.81 | 8.51 | 9.56 | 10.26 | 11.66 | 12.8 | 14.41 | 15.46 | 17.21 | 17.91 | 19.31 | 20.71 | 22.75 | 24.15 | 26.25 | 27.65 |
| r min | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 | 0.25 | 0.25 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | 0.6 | 0.8 | 0.8 | 0.8 | 1 | 1 | 1 | 1 | 1 | 1.2 | 1.2 | 1.6 | 1.6 | 2 | 2 | 2 |
| s max = nominal | 3.2 | 4 | 5 | 5.5 | 6 | 7 | 8 | 10 | 11 | 13 | 16 | 18 | 21 | 24 | 27 | 30 | 34 | 36 | 41 | 46 | 50 | 55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 |
| s A min | 3.02 | 3.82 | 4.82 | 5.32 | 5.82 | 6.78 | 7.78 | 9.78 | 10.73 | 12.73 | 15.73 | 17.73 | 20.67 | 23.67 | 26.67 | 29.67 | 33.38 | 35.38 | / | |||||||||||
| s B min | 2.9 | 3.7 | 4.7 | 5.2 | 5.7 | 6.64 | 7.64 | 9.64 | 10.57 | 12.57 | 15.57 | 17.57 | 20.16 | 23.16 | 26.16 | 29.16 | 33 | 35 | 40 | 45 | 49 | 53.8 | 58.8 | 63.1 | 68.1 | 73.1 | 78.1 | 82.8 | 87.8 | 92.8 |
These dimensions are critical for manufacturing and inspection. For example, the head height (k) ensures proper seating, while the width across flats (s) determines tool compatibility. Non-preferred sizes like M3.5 are used in specific applications.
Technical Requirements and Referenced Standards
ISO 4017:2022 outlines technical conditions for materials, threads, mechanical properties, tolerances, surface treatments, and acceptance. Materials are divided into steel and stainless steel, with general requirements per ISO 8992.
| Catégorie | Subcategory | Acier | Acier inoxydable |
|---|---|---|---|
| Matériels | – | Acier | Acier inoxydable |
| Exigences générales | – | ISO 8992 | |
| Thread | Tolerance | 6g | |
| Standard | ISO 965-1 | ||
| Propriétés mécaniques | Grade | M1.6 ≤ d ≤ M39: 4.8, 5.6, 8.8, 10.9, 12.9/12.9; d > M39: by agreement | M1.6 ≤ d ≤ M24: A2-70, A4-70, A4-80, D4-80, D6-80; M24 < d ≤ M39: A2-50, A2-70, A4-50, A4-70, D4-70, D6-70; d > M39: by agreement |
| Standard | ISO 898-1 | ISO 3506-1 | |
| Tolerances | Qualité du produit | d ≤ 24 mm and l ≤ 10d or 150 mm (smaller value): A; d > 24 mm or l > 10d or 150 mm (smaller value): B | |
| Standard | ISO 4759-1 | ||
| Surface Finish | – | Untreated; Electroplating per ISO 4042; Non-electrolytic zinc flake per ISO 10683; Hot-dip galvanized per ISO 10684 | Clean and bright; Passivation per ISO 16048 |
| – | Other requirements by agreement | ||
| Surface Discontinuities | – | Limits per ISO 6157-1, and ISO 6157-3 for class 12.9/12.9 | By agreement (ISO 6157-1) |
| Acceptance and Packaging | – | ISO 3269 | |
These requirements ensure screws meet performance criteria. For steel, property classes indicate tensile strength; for stainless, they denote corrosion resistance. Tolerances prevent fit issues, while surface treatments protect against environmental factors.
Applications and Implementation
ISO 4017 screws are applied in structural assemblies, machinery, and equipment where reliable fastening is required. In construction, M20-M36 sizes support heavy loads. In automotive, smaller sizes like M6-M12 ensure component security.
Implementation involves selecting grade based on size and length, verifying material per application (e.g., stainless for corrosive environments). Quality control includes dimensional checks and mechanical testing per referenced standards.
Best practices: Use calibrated tools for installation, apply appropriate torque, and inspect for defects. In high-vibration settings, pair with lock washers. This standard impacts R&D by standardizing designs, aiding in simulation and prototyping.
For quality assurance, batch testing per ISO 3269 is recommended. In global supply chains, compliance facilitates exports. Case studies show reduced failures in bridge construction using grade 8.8 screws.
FAQ
- What is the difference between product grades A and B in ISO 4017:2022?
- Grade A provides tighter tolerances for screws where d ≤ 24 mm and length ≤ 10d or 150 mm (whichever smaller), suitable for precision applications. Grade B has looser tolerances for larger or longer screws, balancing cost and performance.
- How do I select the appropriate mechanical property class for hexagon head screws?
- Choose based on load requirements: For steel, classes like 8.8 offer high strength; for stainless, A4-70 provides good corrosion resistance. Refer to ISO 898-1 or 3506-1 for details, considering environment and stress.
- What surface treatments are recommended for corrosion protection?
- For steel: Electroplating (ISO 4042), zinc flake (ISO 10683), or hot-dip galvanizing (ISO 10684). For stainless: Passivation (ISO 16048) enhances natural resistance. Select based on exposure conditions.
- Are there limitations for sizes over M39?
- Yes, mechanical properties and some dimensions for d > M39 are by supplier-buyer agreement, as standard values may not apply due to manufacturing challenges.
- How does ISO 4017 compare to similar standards like DIN 931?
- ISO 4017 is the international equivalent to DIN 931 for partially threaded hex bolts, with similar dimensions but ISO emphasizing global harmonization and updated tolerances.
- What should I check during inspection of these screws?
- Verify dimensions (e.g., s, k, pitch), thread quality (6g tolerance), surface finish, and mechanical properties. Use ISO 3269 for acceptance procedures to ensure compliance.
