Overview
EN ISO 3887:2023 - Steels: Determination of the depth of decarburization is a CEN-endorsed adoption of ISO 3887:2023 that defines decarburization in steel and specifies three validated methods for measuring the depth of decarburization. The standard applies to finished steel products and gives guidance on sampling, specimen preparation and measurement. It supersedes EN ISO 3887:2018 and includes an update noting the use of automatic image analysis for metallographic assessment.
Key topics and technical requirements
- Definition of decarburization: distinguishes between partial decarburization (distance from the point where carbon exceeds ferrite solubility to the unaffected core) and complete (ferrite) decarburization (surface to the point where only ferrite is present). Also defines depth of functional and total decarburization (DD).
- Three measurement methods specified:
- Metallographic method (microstructure examination) - the default unless another method is agreed; suitable where carbon changes produce microstructural contrast.
- Micro-indentation hardness methods - Vickers or Knoop hardness profiling for hardened or quenched & tempered steels (references ISO 6507-1 and ISO 4545-1).
- Carbon-content based methods - chemical analysis, spectrographic analysis, EPMA (electron probe microanalysis) and GDOES (glow discharge optical emission spectrometry).
- Sampling and specimen preparation:
- Cut specimens perpendicular to the longitudinal axis and examine transverse planes to assess peripheral variation.
- Exclude corner regions that may show abnormal decarburization.
- For sections ≤ ~2.5 mm (?) diameter the whole cross-section is polished and examined; for larger sections, use an agreed sampling scheme (see standard).
- Measurement conditions:
- Test on the as‑delivered condition unless otherwise agreed; if additional heat treatment is applied, take precautions to avoid altering carbon distribution.
- Choice of method depends on degree of decarburization, microstructure, carbon content and component geometry.
- Reporting: test report requirements and interpretation rules are included (see clause 6 and 5.4).
Applications and users
EN ISO 3887:2023 is used for quality control and acceptance testing where surface carbon loss affects performance. Typical users include:
- Steel producers and rolling mills
- Heat-treatment and forging shops
- Metallurgical and quality control laboratories
- Automotive, bearing, fastener and engineering component manufacturers
- Inspection bodies and specification writers
Practical uses: verifying heat-treatment processes, assessing functional integrity of components, ensuring compliance with product standards, and failure investigation where surface carbon loss is suspected.
Related standards
Key normative references in EN ISO 3887:2023 include:
For full measurement procedures, tolerances and reporting formats consult the full EN ISO 3887:2023 text available from ISO/CEN.
