Overview
ISO 2740:2023 specifies the geometry and manufacture of tensile test pieces for sintered metal materials (excluding hardmetals). It defines die cavity dimensions for specimens made by pressing-and-sintering and by metal injection moulding (MIM), and the dimensional requirements for machined tensile test pieces from sintered and powder-forged materials. The standard ensures reproducible specimen preparation so tensile testing produces comparable, reliable results.
Key topics and requirements
- Scope: Applies to all sintered metals and alloys except hardmetals; excludes testing method details beyond specimen geometry.
- Test method & calibration: Specimens are to be tested in accordance with ISO 6892‑1; tensile machines calibrated to Class 1 per ISO 7500‑1. Data shall be reported for three or more specimens.
- Pressed & sintered specimens:
- Thickness range of test pieces: 5 mm to 6.5 mm; a thickness tolerance of 1.5 mm accommodates powder density variation.
- Gauge marks may be lightly scribed 25 mm apart; thickness variation between marks must not exceed 0.04 mm.
- Metallographic inspection to confirm no microlaminations longer than 0.25 mm.
- Die design and tooling:
- Permitted die cavity geometries are illustrated in the standard; hardmetal (carbide) dies recommended and dies may include a small exit taper (example: 0.01 mm per side) to ease ejection.
- For repressing, a second die with cavity dimensions enlarged by up to 0.5 % may be used; dies should be supported (e.g., shrink rings) and top‑punch hold‑down is recommended to reduce cracking.
- MIM specimens: Separate die cavity types and guidance for hole locations (for hardened pins) and gating/ejector placement; die dimensions assume typical sintering shrinkage (document provides specific cavity tables and figures).
- Machined specimens:
- Button‑head and other cylindrical geometries shown; button‑head convenient from a 10 × 10 × 75 mm bar.
- Inner shoulder radius recommended between 1.5 mm and 2.5 mm.
- Use for heat‑treated/brittle materials or where low elongation is expected.
Applications and users
ISO 2740:2023 is used by:
- Powder metallurgy manufacturers (pressed‑sintered and MIM producers)
- Materials testing and quality control laboratories
- R&D teams developing sintered alloys and heat treatments
- OEMs and procurement teams requiring standardized tensile data for supplier qualification
Practical benefits:
- Ensures consistent specimen geometry for comparable tensile results
- Guides die and tooling design to minimize defects (cracks, microlaminations)
- Defines specimen choices appropriate for as‑sintered vs. heat‑treated conditions
Related standards
- ISO 6892‑1 - Metallic materials - Tensile testing at room temperature
- ISO 7500‑1 - Calibration/verification of static uniaxial testing machines
Keywords: ISO 2740:2023, sintered metal materials, tensile test pieces, MIM tensile specimens, pressed and sintered, die cavity dimensions, machined tensile pieces, powder metallurgy testing.
