EN ISO 10669:1999

Overview

EN ISO 10669:1999 specifies the standards for plain steel washers used in tapping screw and washer assemblies. It addresses both the normal and large series of plain washers and defines product grade A, ensuring consistency in dimensions, mechanical properties, and surface finish. This international standard, adopted by the European Committee for Standardization (CEN), aligns with ISO 10669:1999 and applies to plain washers compatible with ISO 10510 tapping screw assemblies.

The standard provides a unified framework that ensures the quality and interchangeability of washers used in fastening applications. It is particularly relevant to manufacturers, quality controllers, and engineers involved in mechanical assembly and fastening solutions.

Key Topics

• Washer Types and Series

  • Type N (Normal series)
  • Type L (Large series)
    Each type defines specific dimensions such as clearance hole, outside diameter, and thickness, tailored to nominal screw sizes ranging from 2.2 mm to 9.5 mm.

• Material and Hardness

  • Plain steel with a carbon content not exceeding 0.12%
  • Hardness class starting at 180 HV, with mechanical properties ranging between 180 HV to 300 HV (measured according to ISO 6507-1)
  • The washers are designed to withstand assembly conditions without compromising structural integrity.

• Dimensional Tolerances and Surface Finish

  • Defined tolerances based on product grade A as per ISO 4759-3
  • Washers supplied in plain (natural) finish or treated with protective lubricants or coatings agreed between supplier and customer
  • Electroplating requirements referenced in ISO 4042
  • Surface roughness and workmanship standards ensure washers are free from burrs and defects.

• Compliance and Inspection

  • Acceptance inspection procedures follow ISO 3269
  • Emphasis on preventing irregularities to maintain assembly reliability.

• Designation System

  • A clear format for specifying washers, e.g., Washer ISO 10669 - N - 4.2 - 180 HV, denoting series type, nominal size, and hardness class.

Applications

EN ISO 10669:1999 washers are essential components in:

• Tapping screw and washer assemblies used for metal fastening tasks in manufacturing and construction
• Precision mechanical engineering where high consistency and reproducibility of washer dimensions and hardness are critical
• Automotive and aerospace industries requiring reliable joint security with standardized fastening elements
• Electrical and electromechanical assemblies where vibration resistance and surface protection through coatings are important
• General industrial assembly involving sheet metal fastening requiring standardized plain washers for optimal performance.

The standard facilitates interchangeability and quality assurance, reducing production discrepancies and enhancing the efficiency of assembly lines.

Related Standards

• ISO 10510 - Specifies tapping screw and washer assemblies that EN ISO 10669 washers complement
• ISO 3269 - Fasteners acceptance inspection procedures applicable to washers
• ISO 4042 - Electroplated coatings on fasteners, including washers
• ISO 4759-3 - Tolerances for plain washers, detailing product grades including Grade A
• ISO 6507-1 - Vickers hardness test method for metallic materials, applied in washer hardness testing

Understanding and integrating these related standards help ensure full compliance within fastener and washer assembly processes, promoting international trade standardization and quality improvement.

By adhering to EN ISO 10669:1999, manufacturers and engineers benefit from standardized dimensions, reliable material properties, and consistent quality for plain washers used with tapping screw assemblies. This improves product reliability, facilitates global compatibility, and supports quality management in fastener production and use.