ISO 3506-1:2020 is an International Standard that specifies mechanical and physical property requirements for corrosion-resistant stainless steel bolts, screws, and studs with defined stainless grades and property classes.
If you need help mapping your fastener type, property class, or test plan to the correct edition and scope, contact our team for guidance before you lock in equipment or procedures.
ISO 3506-1:2020 — Fasteners — Mechanical properties of corrosion-resistant stainless steel fasteners — Part 1: Bolts, screws and studs with specified grades and property classes
ISO 3506-1 is used when a stainless steel externally threaded fastener must meet a defined property class, and the lab or QA team needs a standards-based path to verify key mechanical/physical requirements for that class.
This standard is commonly referenced in purchasing specifications, incoming inspection plans, manufacturing quality plans, and supplier qualification for stainless fasteners used in corrosive or hygiene-sensitive environments.
Quick definition
Document type: International Standard specifying property requirements (mechanical and physical) for stainless steel bolts, screws, and studs, organized by grades and property classes.
In scope: Externally threaded fasteners with ISO metric threads (coarse and fine pitch) made from corrosion-resistant stainless steels, including austenitic, martensitic, ferritic, and duplex grades.
Not covered: Functional performance requirements such as torque/clamp-force behavior, shear strength, fatigue resistance, or weldability; and set screws / similar threaded fasteners not under tensile stress.
| Scope item | What ISO 3506-1 addresses |
|---|---|
| Fastener types | Bolts, screws, and studs (externally threaded fasteners) |
| Threads | ISO metric coarse and fine pitch threads (within the document’s stated size ranges) |
| Test temperature basis | Property requirements are evaluated at ambient conditions (with cautions for performance outside typical service temperature ranges) |
| Property class system | Defines requirements by stainless grade families and property classes for fasteners |
What this standard covers
ISO 3506-1 defines a requirements framework for stainless steel bolts, screws, and studs by linking stainless grade families to property classes and specifying the mechanical/physical performance requirements associated with those classes.
It applies to fasteners with ISO metric screw threads and includes both coarse and fine pitch thread forms within the standard’s stated size limits. It also notes that geometry can affect whether a specific fastener design can meet certain tensile or torsional requirements.
ISO 3506-1 is not a corrosion test standard and does not define performance items such as torque–tension behavior or fatigue resistance. When those functional properties are critical, they typically require additional specifications and test methods beyond ISO 3506-1.
Why this standard matters in testing
For stainless fasteners, the property class is often the key acceptance criterion for mechanical performance. ISO 3506-1 provides a common technical basis to qualify product lots, verify supplier compliance, and document incoming inspection results using a recognized property class system.
Because the requirements are tied to stainless grade families and property classes, correct identification of the fastener type and cited property class is essential before selecting fixtures, force capacity, and measurement tools.
Common materials, product types, or applications covered
Common product types: Stainless steel bolts, screws, and studs specified by property class for general industrial assemblies, equipment builds, and maintenance replacement programs.
Common stainless grade families referenced: Austenitic, martensitic, ferritic, and duplex stainless steels (as used for corrosion-resistant fasteners).
Common application drivers: Corrosive exposure, washdown/hygiene requirements, outdoor service, marine/coastal service, and equipment where stainless fasteners are preferred for environmental resistance and cleanliness.
Common test or verification workflow
ISO 3506-1 is typically used as an acceptance standard, meaning the workflow is focused on verifying that a fastener lot meets the property class requirements stated on drawings, purchase orders, or product documentation.
Common workflow: (1) confirm the fastener type and cited property class, (2) select representative samples from the lot, (3) perform the required mechanical/physical verification tests for that class using the specified conditions, and (4) report results with clear traceability to the cited ISO 3506-1 edition and the fastener identification.
Temperature sensitivity: Requirements are evaluated at ambient conditions, and users should treat service at elevated or very low temperatures as an engineering decision that may require additional review beyond the base acceptance testing.
Equipment commonly used for this standard
Because ISO 3506-1 is a property-class requirements standard (not a single stand-alone “one test” method), equipment selection is typically driven by the specific verification tests and the fastener geometry and size.
Common equipment families: Universal testing machines (UTMs) for tension and related mechanical verification on fasteners, appropriate fastener grips/fixtures to safely load bolts/screws/studs, and measurement tools used to support mechanical/physical property verification and documentation.
Practical selection note: Certain head or shank geometries can limit achievable loadability, so fixture choice and alignment control matter—especially when comparing results across different fastener designs and sizes.
If you are matching UTM capacity, fixtures, and measurement options to a specific ISO 3506-1 property class and fastener size range, you can request a detailed quote for a configuration built around your verification workflow.
How to read this designation or revision
ISO 3506-1 identifies Part 1 of the ISO 3506 series (covering bolts, screws, and studs). The suffix :2020 indicates the publication year of that edition.
When ISO 3506-1 is cited in a contract or inspection plan, the exact edition matters because requirements, referenced documents, and property class details can change between revisions. ISO identifies ISO 3506-1:2020 as the current published edition, and earlier editions such as ISO 3506-1:2009 are identified as withdrawn in the standard’s life-cycle history.
Related standards, methods, or frameworks
ISO 3506-1 references other ISO documents for thread forms and tolerances and points to additional parts of the ISO 3506 series for related fastener types and selection guidance.
- ISO 3506-3: Set screws and similar fasteners not under tensile stress (not covered by ISO 3506-1).
- ISO 3506-5: Guidance supporting selection of stainless grades/property classes for higher-temperature use cases.
- ISO 3506-6: General rules and additional technical information on suitable stainless steels and their properties.
- ISO 68-1, ISO 261, ISO 262, ISO 965-1, ISO 965-2: ISO metric thread profile, diameter/pitch combinations, and thread tolerances referenced by ISO 3506-1.
Talk with us about ISO 3506-1 test equipment and setup
If you are setting up or upgrading fastener verification for ISO 3506-1—especially across multiple diameters, head styles, or property classes—talk with our team about a practical equipment and fixturing path for your lab.