ISO 3643:2024

Overview

ISO 3643:2024 - Rolling bearings - Ceramic rolling elements - Terms and characteristics of surface imperfections provides a standardized vocabulary, visual descriptions and representative images for surface imperfections found on finished silicon nitride rolling elements (balls and rollers). Published as the first edition in 2024, the document classifies imperfections by optical appearance, describes their visual characteristics under common inspection methods, and includes informative annexes on inspection techniques. It does not set acceptance limits, address geometric product specification (GPS) deviations, or prescribe inspection acceptance criteria.

Key topics and requirements

• Scope and definitions: Clear terms and definitions consistent with ISO 5593 and industry practice, including the deprecated term “surface defect” and the recommended use of “surface imperfection.”
• Classification: Imperfections grouped into four families based on optical appearance, enabling consistent reporting and communication across suppliers and customers.
• Detailed imperfection descriptions: Names and characteristics for specific types such as:
  • Cracks (open crack, partially healed crack, C-crack, star crack)
  • Linear hollow indications (scratch, cut, contact mark)
  • Irregular or rounded hollow indications (pore, missing material, flat)
  • Optically variable regions (snowflakes, inclusion, colour variation, smearing, healed crack, non cleaned-up area)
• Imaging and inspection guidance: Typical photos and imaging modalities used for identification:
  • Optical microscopy (bright field / dark field, magnification generally <100× for production control)
  • Dye penetrant inspection (informative Annex B)
  • Scanning electron microscopy (SEM) for pattern specification (informative Annex C)
• Non-prescriptive: The standard describes identification and appearance; selection of inspection methods, parameters, and acceptance limits is left to agreement between manufacturers, assemblers and end users.

Practical applications

• Standardizes communication about surface appearance among ceramic rolling element manufacturers, bearing assemblers, OEMs (automotive, aerospace, industrial machinery), and quality/inspection teams.
• Supports incoming inspection, process control and root-cause analysis by providing a common vocabulary and representative images.
• Useful in supplier contracts and technical specifications to reference defined imperfection types without prescribing acceptance thresholds.
• Assists in selection and integration of non-destructive testing (NDT) methods (visual, dye penetrant, SEM and other complementary NDT techniques).

Who should use ISO 3643:2024

• Manufacturers and suppliers of silicon nitride rolling elements
• Bearing design engineers and OEM procurement teams
• Quality assurance and inspection personnel
• Lab technicians performing microscopy, dye penetrant or SEM analyses

Related standards

• ISO 5593 (Rolling bearings - Vocabulary) is referenced for terminology.
  Note: ISO 3643:2024 is descriptive and intended to be used alongside application-specific acceptance criteria agreed between parties.