ISO 4017 Hex Head Bolt

About ISO 4017 Hex Head Bolt

The Stainless Steel ISO 4017 Hex Head Bolt (internationally classified as a hex head screw) is a globally standardized, high-performance fastener featuring a six-sided hexagonal head and a fully threaded shank. Governed by the International Organization for Standardization, the ISO 4017 standard specifies strict metric dimensions, serving as the modern global successor to the older German DIN 933 standard. Because it is threaded all the way to the underside of the head, it allows full thread engagement across its entire length, providing exceptional clamping force in compact joints and shallow, pre-tapped holes.

Key Features & Design

• Fully Threaded Profile: Continuous threading from the tip to the head ensures uniform grip and maximum locking force, making it ideal for components with pre-threaded matching holes.

• Hexagonal Drive Profile: Optimized for stable external wrenching, allowing operators to apply maximum torque using standard spanners, sockets, or impact tools.

• Global Tolerances: Strictly divided into Product Grade A (for precise fits in sizes M1.6 to M24 and lengths up to 150mm) and Product Grade B (for diameters over M24 or lengths exceeding 150mm).

• Aesthetic Metallic Finish: The natural, polished stainless steel surface provides a clean look that avoids rust-bleeding, removing the need for superficial anti-corrosion coatings.

Material Grades & Specifications

Per global fastener requirements like ISO 3506-1, ISO 4017 bolts are cold-worked from premium austenitic stainless steel families:

• A2 Stainless Steel (Grade 304): The most prevalent standard grade, formulated with an 18/8 Chromium-Nickel base. It delivers excellent corrosion resistance in typical outdoor atmospheres, moisture-heavy structures, and internal framing.

• A4 Stainless Steel (Grade 316): A premium, acid-proof marine grade fortified with Molybdenum. It actively stops pitting, crevice corrosion, and chloride cracking in heavy chemical plants or salt-spray maritime environments.

• Property Class: Most frequently cold-formed to Class 70 (A2-70 or A4-70), certifying a baseline tensile strength of 700 MPa.

ISO 4017 vs. DIN 933 Dimensional Differences

While ISO 4017 directly updates the old DIN 933 standard, engineers must verify tool compatibility as the Width Across Flats (WAF / wrench size) varies slightly on key metric diameters:

• M10 Diameter: ISO 4017 specifies a 16 mm WAF (reduced from the DIN 933 profile of 17 mm).

• M12 Diameter: ISO 4017 specifies an 18 mm WAF (reduced from the DIN 933 profile of 19 mm).

• M14 Diameter: ISO 4017 specifies a 21 mm WAF (reduced from the DIN 933 profile of 22 mm).

• M22 Diameter: ISO 4017 specifies a 34 mm WAF (increased from the DIN 933 profile of 32 mm).

Technical Parameters

• Size Range: Produced comprehensively from M1.6 up to M64 nominal thread diameters.

• Thread Geometry: Machined precisely to metric coarse pitch thresholds adhering to a standard 6g thread tolerance class.

• Operating Range: Capable of executing secure joints across extreme thermal shifts, maintaining integrity from sub-zero conditions up to heavy industrial operational heat.

Target Applications & Industries

• Renewable Energy Infrastructure: Securing solar PV racking structures, tracking brackets, and internal wind turbine electrical units.

• Process & Chemical Engineering: Flange bolt assemblies on pipelines, pumps, and mixing tanks managing corrosive fluids.

• Automotive & Transport: High-vibration installations in vehicle chassis, EV charging station framing, and plant assembly lines.

• Hygienic & Cleanroom Settings: Selected across food-processing arrays, medical hardware, and data centres due to non-magnetic, sterile, and easily cleaned surfaces.