RapidBoltISO FastenerStandards
Internationally recognised fastener standards for hex bolts, nuts, washers, and stud bolts. ISO specifications ensure dimensional interchangeability and consistent mechanical performance across global supply chains.
What Are ISO Fastener Standards?
The International Organization for Standardization (ISO) develops and publishes globally harmonised standards for fastener dimensions, mechanical properties, and material requirements. ISO fastener standards are the foundation of the metric fastener system and are adopted worldwide for industrial, structural, and engineering applications.
For industries such as Oil & Gas, LNG, Power Generation, Mining, and Infrastructure, ISO standards ensure dimensional interchangeability between manufacturers, consistent mechanical performance, and internationally recognised quality benchmarks. Many ISO standards are equivalent to or harmonised with DIN and EN standards.
Dimensional Standards
Precise thread, head, and body dimensions ensuring global interchangeability between suppliers.
Property Classes
Defined tensile strength, yield, and hardness per ISO 898-1 (steel) and ISO 3506 (stainless).
Global Acceptance
Internationally recognised metric system used across all continents and major industries.
Traceability & Certification
EN 10204 Type 3.1 certificates with full heat number traceability for audit compliance.
"EMG supplies ISO metric fasteners across all major property classes — from 8.8 carbon steel hex bolts to A4-80 stainless steel stud bolts — with EN 10204 3.1 certification, full heat number traceability, and global shipping capability."
— Energy Materials Group
ISO Fastener Standards We Supply
Our comprehensive inventory covers the most widely specified ISO fastener standards for metric industrial applications, with full certification and traceability.
Hex Bolts & Hex Screws
ISO dimensional standards for hexagon head bolts and screws — the most commonly specified fasteners in industrial and structural applications worldwide.
Partial Thread (Bolts)
Hexagon head bolts — Product grades A and B. Partial thread with defined shank length. The primary international standard for hex bolts.
Equivalent: DIN 931
Hexagon head bolts — Product grade C. Wider tolerances for general-purpose applications where precision is less critical.
Equivalent: DIN 601
Full Thread (Screws)
Hexagon head screws — Product grades A and B. Full thread from head to tip. Used where full thread engagement is required.
Equivalent: DIN 933
Hexagon head screws — Product grade C. Full thread with wider tolerances for non-precision assemblies.
Equivalent: DIN 558
Applications: Flanged joints, pressure equipment, structural steelwork, piping systems, machinery, and general engineering assemblies.
Hexagon Nuts
ISO dimensional and mechanical property standards for hexagon nuts designed to pair with ISO 4014 and ISO 4017 bolts.
Hexagon nuts, Style 1. Standard height nut for general-purpose bolting. Product grades A and B.
Equivalent: DIN 934
Hexagon nuts, Style 2. Increased height for higher proof loads and better fatigue resistance.
Equivalent: —
Hexagon thin nuts (chamfered). Reduced height for locking and low-profile applications.
Equivalent: DIN 439
Prevailing torque type all-metal hexagon nuts. Self-locking for vibration-prone assemblies.
Equivalent: DIN 980
Plain Washers
ISO standards for flat washers used to distribute bearing loads and protect surfaces under bolt heads and nuts.
Plain washers — Normal series, Product grade A. Without chamfer. The standard metric flat washer.
Equivalent: DIN 125A
Plain washers — Normal series, Product grade A. With chamfer on one face for bolt rotation.
Equivalent: DIN 125B
Plain washers — Normal series, Product grade C. Wider tolerances for general use.
Equivalent: DIN 126
Plain washers — Large series. Larger OD for extra bearing area on soft or thin materials.
Equivalent: DIN 9021
Stud Bolts & Threaded Rod
ISO and DIN standards for double-end stud bolts and fully threaded rod used in flanged connections, pressure vessels, and structural assemblies.
Stud Bolts
End of products — general standard covering chamfer and thread run-out requirements for studs and bolts.
Double-end stud bolts with interference fit (DIN 938) and metal-to-metal (DIN 939) thread engagement for tapped holes.
Stud bolts — fully threaded or partial thread configurations. Commonly used for flange bolting to ASME B16.5 with metric threads.
Common Grades: 8.8, 10.9, B7 equivalent
Threaded Rod
Threaded rod — continuous thread in standard 1-metre or 3-metre lengths. Available in property classes 4.6, 8.8, 10.9, and stainless A2/A4.
All stud bolts and threaded rod supplied to ISO 898-1 property class requirements with matching nuts to ISO 898-2.
Applications: Flange bolting, pressure vessel connections, structural assemblies, pipe supports, and anchor bolt systems.
ISO 898 — Carbon & Alloy Steel Properties
Mechanical properties of fasteners made of carbon steel and alloy steel.
800 MPa tensile, 640 MPa yield. Medium carbon steel, quenched and tempered. The most common high-strength grade.
1040 MPa tensile, 940 MPa yield. Alloy steel for high-strength structural and pressure applications.
1220 MPa tensile, 1100 MPa yield. Alloy steel for critical high-strength applications.
Part 1: Bolts, screws, and studs.Part 2: Nuts.
ISO 3506 — Stainless Steel Properties
Mechanical properties of corrosion-resistant stainless steel fasteners.
Austenitic 304 type, 700 MPa tensile. General corrosion resistance for non-marine environments.
Austenitic 316 type with molybdenum, 800 MPa tensile. Superior corrosion resistance for marine and chemical environments.
Martensitic stainless steel, 700 MPa tensile. Heat treatable for higher hardness with moderate corrosion resistance.
Applications: Marine, chemical, food processing, pharmaceutical, and water treatment industries.
ISO vs DIN vs EN — Standard Equivalence
Many legacy DIN standards have been superseded by harmonised ISO and EN standards. Understanding equivalence is essential for procurement and engineering specifications.
Hex Bolts
- ISO 4014 ≈ DIN 931
- ISO 4017 ≈ DIN 933
- ISO 4016 ≈ DIN 601
- ISO 4018 ≈ DIN 558
Nuts
- ISO 4032 ≈ DIN 934
- ISO 4035 ≈ DIN 439
- ISO 7042 ≈ DIN 980
- ISO 7040 ≈ DIN 985
Washers
- ISO 7089 ≈ DIN 125A
- ISO 7090 ≈ DIN 125B
- ISO 7093 ≈ DIN 9021
- ISO 7091 ≈ DIN 126
Properties
- ISO 898-1 (steel bolts)
- ISO 898-2 (steel nuts)
- ISO 3506-1 (SS bolts)
- ISO 3506-2 (SS nuts)
Certification, Traceability & Quality
Every ISO fastener we supply comes with comprehensive documentation to ensure project compliance, audit readiness, and material authenticity. Our quality management system is certified to ISO 9001:2015.
EN 10204 Type 3.1 Certification
Material test certificates with chemical composition, mechanical properties, and heat treatment records validated by an independent inspector.
Heat Number Traceability
Every fastener can be traced back to its original heat of steel, providing complete material provenance for critical applications.
PMI Testing
Positive Material Identification available to verify alloy composition matches specified requirements.
ISO 9001:2015 Quality System
Our certified quality management system ensures consistent processes, documented procedures, and continuous improvement.
Products We Supply
Available in metric sizes M5 through M150 with full property class range and short lead times.
Related Standards & Products
Frequently Asked Questions
What is the difference between ISO 4014 and ISO 4017?
ISO 4014 specifies hexagon head bolts with a partial (non-full) thread length, leaving an unthreaded shank section beneath the head. ISO 4017 specifies hexagon head screws with full thread from head to tip. ISO 4014 is preferred for structural and flange connections where the unthreaded shank section carries shear loads.
What do ISO 898-1 property classes mean?
The two-digit class designation (e.g., 8.8) indicates mechanical properties: the first number multiplied by 100 gives the minimum ultimate tensile strength in MPa (800 MPa), and the second number divided by 10 gives the ratio of yield to tensile strength (80%). So Class 8.8 has 800 MPa tensile and 640 MPa yield strength.
What is the ISO equivalent of DIN 934?
ISO 4032 (Style 1 hexagon nut) is the internationally harmonised replacement for DIN 934. While dimensionally very similar, there are minor differences in chamfer angle and across-flats tolerances for certain sizes. Always verify the specific standard required by your project specification.
Can ISO metric fasteners be used with ASTM specifications?
Yes, many projects use ISO metric dimensional standards (e.g., ISO 4014/4017 for hex bolt dimensions) combined with ASTM material specifications (e.g., A193 B7 for material properties). EMG can supply metric-dimensioned fasteners to ASTM material grades with full dual certification.
Get ISO-Compliant Fasteners for Your Project
If you require ISO metric fasteners for a critical project, our technical team can assist with standard selection, property class specification, and competitive supply solutions.
Global Supply Capability: We supply ISO metric fasteners worldwide with competitive lead times. Emergency and expedited delivery available for critical projects.