Overview
EN ISO 2740:2023 - Sintered metal materials, excluding hardmetals - Tensile test pieces (ISO 2740:2023) - defines standard geometries and manufacturing details for tensile test specimens used to evaluate sintered metals and alloys (excluding hardmetals). Published by CEN/ISO, this standard specifies die cavity dimensions for pressed-and-sintered and metal injection moulded (MIM) specimens, plus the dimensions and handling of machined test pieces produced from sintered or powder‑forged materials.
Key topics and technical requirements
- Scope: Applies to all sintered metals and alloys except hardmetals; supersedes EN ISO 2740:2009.
- Test method references: Requires tensile testing in accordance with ISO 6892-1 and force‑measuring calibration to ISO 7500-1.
- Pressed & sintered specimens:
- Recommended thickness range: 5 mm to 6.5 mm (with an accommodating thickness tolerance).
- Gauge marking: optional light scribe marks 25 mm apart; gauge thickness variation between marks limited.
- Metallographic check: inspect for microlaminations; maximum acceptable microlamination length specified.
- Die specifications:
- Die cavity geometries are defined for standard, serrated and high‑strength test pieces (figures provided in the standard).
- Dies are preferably made of hardmetal; optional small exit taper (e.g., 0.01 mm per side) to ease ejection; repressing dies may be up to 0.5% larger.
- Design considerations to reduce cracking and slippage (shrink rings, hold‑down punches, serrations or 20° wedge faces for gripping).
- MIM test pieces:
- Two MIM die types (larger and smaller) are described; cavities account for sintering shrinkage (typical design assumptions provided).
- Holes may be moulded or drilled post‑sintering to accept hardened pins for clevis gripping.
- Machined test pieces:
- Button‑head and cylindrical geometries defined (example: machined from a standard bar).
- Specific guidance for heat‑treated materials, surface preparation, and when small diameters (