ISO 4386-3:2018

Overview

ISO 4386-3:2018 specifies a non‑destructive penetrant testing (liquid penetrant inspection, LPI) method for metallic multilayer plain bearings. The standard is focused on detecting bond defects in transitional areas between bearing backing and bearing material (end faces and joint faces) and on identifying surface discontinuities on the sliding surface that are not always detectable by ultrasonic methods. It applies, in principle, to finished multilayer plain bearings-most commonly cast bearings with steel, cast steel or cast bronze backings-and is intended for use by trained NDT personnel.

Key topics and requirements

• Scope of inspection
  • Detects bond defects in transitional areas and discontinuities in sliding surfaces.
  • Not suitable for backings that cannot be tin‑plated (e.g., perlitic cast iron, stainless steels, cast aluminium).
• Preparation
  • Surfaces must be clean and dry; maximum drying temperature 55 °C.
  • Surface roughness requirement: R ≤ 5 µm.
  • Mechanical and chemical pre‑cleaning procedures are specified to avoid sealing defects.
• Penetrant application
  • Use water‑removable or solvent‑removable penetrants.
  • Test surface temperature: 10 °C to 50 °C.
  • Penetration time: 10–20 minutes (≥20 min for very viscous penetrants).
• Removal of excess penetrant
  • Water‑based: rinse with water at hydrostatic pressure < 2 bar (no detergents).
  • Solvent‑based: wipe with cloth lightly moistened with appropriate solvent.
• Developer
  • Apply immediately after drying; ensure a thin, uniform film as per manufacturer instructions.
  • Observe indications within 10–20 minutes after developer application.
• Inspection and acceptance
  • Surface inspection classified into five quality classes (A–E) with defined limits for mark size, number and total area per 1 dm² (see Annex A).
  • Isolated marks ≤ 1.5 mm are disregarded. Re‑machining and re‑testing recommended for unassessable marks.
• Safety
  • Use trained personnel and appropriate precautions with flammable/volatile chemicals.
• Test report requirements
  • Reference ISO 4386-3:2018, component dimensions/material, penetrant/developer details (manufacturer, product, batch), bond and sliding-surface findings, inspector and date.

Applications and users

• Practical applications
  • Production and final‑inspection quality control of multilayer plain bearings.
  • Non‑production troubleshooting to identify manufacturing defects.
  • Complementary inspection where ISO 4386‑1 ultrasonic testing cannot reveal boundary defects.
• Who uses it
  • Bearing manufacturers, NDT technicians, OEM quality engineers in automotive, aerospace, heavy machinery and industrial equipment.

Related standards

• ISO 4386‑1 - Non‑destructive ultrasonic testing of bond (thickness ≥ 0.5 mm)
• ASTM E1417 - Standard practice for liquid penetrant testing (chemical/media conformity)

Keywords: ISO 4386-3:2018, plain bearings, non-destructive penetrant testing, penetrant inspection, multilayer plain bearings, bond defects, sliding surface, LPI, acceptance criteria, NDT.