ISO 2738:2026

Overview

ISO 2738:2026 is an international standard developed by the International Organization for Standardization (ISO). It outlines standardized methods for the determination of density, oil content, and open porosity in permeable sintered metal materials, explicitly excluding hardmetals. The standard is particularly relevant for porous metal components such as sintered bearings and structural parts produced by pressing and sintering metal powders.

The procedures defined in ISO 2738:2026 support quality assurance and product consistency in powder metallurgy, enabling manufacturers and laboratories to use precise, consistent, and internationally recognized test methods.

Key Topics

ISO 2738:2026 addresses several essential topics related to porous sintered metals:

• Density Determination

  • Includes both dry density and fully impregnated (wet) density measurements.
  • Provides guidance on sample preparation and weighing procedures.

• Oil Content Measurement

  • Outlines how to measure oil content in relation to both total test piece volume and open porosity.
  • Describes methods for extracting oil using solvent extraction (e.g., Soxhlet method).

• Open Porosity Assessment

  • Specifies techniques for fully impregnating samples (e.g., vacuum oil impregnation).
  • Defines the calculation of open porosity based on standardized procedures.

• Sample Handling and Equipment

  • Guidelines on the preparation and handling of test pieces, including cleaning and surface conditioning.
  • Requirements for analytical balances, extractors, weighing devices, and impregnation equipment.

• Result Expression and Precision

  • Describes formulas for calculation and reporting.
  • Provides repeatability and reproducibility metrics for the defined test methods.

Applications

ISO 2738:2026 is widely applicable in both research and industrial environments, particularly where quality control of porous metal components is critical. Common applications include:

• Porous Metal Bearings Production
  Ensuring the optimal balance of density, oil content, and porosity for reliable lubrication and wear resistance.

• Sintered Metal Structural Parts
  Verifying material properties for load-bearing or precision parts made from metal powders.

• Quality Control in Powder Metallurgy
  Providing consistent, comparable measurement data across different batches and manufacturing sites.

• Lab Testing and R&D
  Supporting development and assessment of new alloys, powders, and sintering processes by offering reliable standardized measurements.

• Supplier and Customer Communication
  Using standardized test reports to ensure transparent, verifiable data on critical material characteristics.

Related Standards

ISO 2738:2026 references and aligns with several related standards, which further enhance test methods and data quality:

• ISO 758
  Liquid chemical products for industrial use - Determination of density at 20 °C

  • Provides detailed procedures for measuring liquid density, essential for accurate oil content and porosity calculations.

• ISO 13944
  Lubricated metal-powder mixes - Determination of lubricant content - Soxhlet extraction method

  • Specifies solvent extraction methods vital for removing lubricants from porous test pieces.

• ISO 3448
  Industrial liquid lubricants - ISO viscosity classification

  • Offers viscosity classifications for oils used in impregnation or porosity testing.

Together, these standards create a robust framework for the precise and repeatable characterization of permeable sintered metal materials.

By adhering to ISO 2738:2026, manufacturers, laboratories, and researchers can achieve higher levels of confidence in the performance and specification compliance of sintered metal parts, contributing to greater consistency across the global supply chain for powder metallurgy products.