ISO 3506-7:2024

Overview

ISO 3506-7:2024 is an international standard that specifies the mechanical and physical properties of flat washers made from corrosion-resistant stainless steels. Developed by the International Organization for Standardization (ISO), this document covers washers intended for use in bolted joints, typically combined with bolts, screws, studs, and nuts of specified grades and property classes as per ISO 3506-1 and ISO 3506-2. ISO 3506-7:2024 applies to washers manufactured from austenitic, ferritic, and duplex stainless steels, ensuring reliable performance in varied service environments.

This standard is crucial for industries requiring high-quality, durable, and corrosion-resistant fastening systems, providing a common framework for manufacturers, distributors, and users of stainless steel flat washers.

Key Topics

Stainless Steel Grades and Property Classes

• Material Types: Covers austenitic, ferritic, and duplex stainless steels.
• Designation System: Washers are specified by a standardized system, combining steel grade and property class (e.g., A2-100HV).
• Specification Range: Includes plain, flat, square, square hole washers, and shaped plates with thickness from 0.2 mm to 6 mm.

Mechanical and Physical Properties

• Hardness Classes: Washers are classified by minimum and maximum Vickers hardness values (e.g., 100HV, 200HV, 300HV).
• Corrosion Resistance: Guidance for selecting grades based on resistance to pitting, crevice, and intergranular corrosion.
• Temperature Range: Washers are tested at 10 °C to 35 °C, recommended for –20 °C to +150 °C but may be used from –196 °C up to +300 °C with caution.

Inspection, Marking, and Labelling

• Inspection Methods: Requirements and guidance for manufacturer, supplier, and purchaser inspections.
• Test Reports: Specifies documentation to be agreed at the time of order, following ISO 16228 guidelines.
• Marking: Systems for durability and traceability, including optional marking of washers and mandatory package labelling.

Applications

ISO 3506-7:2024 is highly relevant for sectors where durable bolted connections are critical and exposure to corrosive environments is common. Typical applications include:

• Construction and Civil Engineering: For stainless steel bolted assemblies exposed to outdoor or marine environments.
• Food and Pharmaceutical Equipment: Where hygiene and corrosion resistance are essential.
• Power Generation and Petrochemical: For piping, pressure vessels, and support structures that require robust fastener performance.
• Transport and Automotive: In components exposed to weathering and chemicals, such as rail infrastructure or vehicle frames.

Flat washers compliant with this standard are integral to ensuring long service life, minimizing maintenance, and promoting safety in critical assemblies.

Related Standards

• ISO 3506-1: Mechanical properties of corrosion-resistant stainless steel bolts, screws, and studs.
• ISO 3506-2: Mechanical properties of stainless steel nuts.
• ISO 3506-4: Stainless steel screws forming their own mating thread.
• ISO 3506-6: Selection rules and technical information for stainless steels, including corrosion and magnetic properties.
• ISO 6507-1: Vickers hardness testing method.
• ISO 16228: Types of inspection documents for fasteners.
• ISO 1891-4: Fastener vocabulary including inspection and quality terms.

Understanding and implementing ISO 3506-7:2024 supports compliance, quality assurance, and optimal performance of stainless steel fastener assemblies in a wide array of demanding applications.