Overview
EN ISO 3928:2016 (ISO 3928:2016) specifies the geometry and manufacturing details for fatigue test pieces used with sintered metal materials (excluding hardmetals). The standard covers both pressed-and-sintered specimens made from die cavities and machined specimens from sintered or powder-forged materials. It is published by CEN/ISO and is intended for consistent fatigue testing practice in powder metallurgy and sintered metal evaluation.
Key topics and technical requirements
- Scope: Applicable to all sintered metals and alloys except hardmetals.
- Die cavity dimensions: Defines cavity shapes for producing unnotched and notched fatigue test pieces by pressing and sintering. Recommended die features include tapering (≈0.01 per side) and possible enlargement (≈0.5%) for repressing.
- Test piece dimensions: Drawings and mandatory tolerances are supplied for unnotched and notched specimens. Flatness and parallelism of 0.1 mm are mandatory for gauge faces.
- Notch tooling and wear: Tooling radius (e.g., 5.5 mm mentioned for die) is subject to wear; the corresponding radius in the produced specimen must be reported.
- Material and tooling: Die material should preferably be hardmetal/carbide; die support (e.g., shrink rings) is recommended to reduce lateral expansion during compacting.
- Orientation and loading: Specimen orientation for bending fatigue is defined (torque vector parallel to pressing direction unless stated otherwise).
- Machined specimens: Examples include rotating-beam and axial-loading geometries. Machining guidance: use diamond grinding, longitudinal lapping, final longitudinal polishing, and diameter uniformity within ±0.025 mm. Note: carefully machined circular specimens can show 20–30% higher endurance limits than as-compacted square/rectangular pieces.
- Quality checks: Gauge-region micro-lamination must be ≤ 0.25 mm; edges in gauge area shall be broken to remove burrs.
- Identification requirements: Test reports should include reference to ISO 3928, material type, density, dimensions, finishing treatments, die material, heat treatment state, hardness, and notch radius (where applicable).
Applications
- Standardizes specimen production for fatigue testing of sintered components in research, quality control, and material development.
- Used to validate fatigue properties for powder metallurgy parts, optimize compaction/sintering tooling, and compare fatigue data across laboratories.
- Supports fatigue test methods such as reverse bending, rotating-beam, and axial loading.
Who uses this standard
- Powder metallurgy engineers and metallurgists
- Fatigue testing laboratories and quality control teams
- Tooling designers and die manufacturers
- Materials researchers and certification bodies
Related standards
Keywords: EN ISO 3928:2016, ISO 3928:2016, sintered metal, fatigue test pieces, powder metallurgy, fatigue testing, die cavity dimensions, machined test pieces, notched specimens.