Overview
EN ISO 7046-2:2011 specifies requirements for countersunk flat head screws (common head style) with a type H or type Z cross recess, product grade A. It covers screws with metric threads M2 up to and including M10 and addresses steel screws of property class 8.8, stainless‑steel screws A2‑70, and non‑ferrous metal screws CU2 / CU3. This harmonized CEN/ISO standard defines geometry, recess penetration depth options, materials, tolerances and referencing normative fastener standards for design, manufacture and acceptance.
Key Topics
- Scope & thread sizes: Threads M2–M10, grade A fasteners.
- Cross recess types: Type H and Z cross recess forms (ISO 4757) with two penetration depth series:
- Series 1 (deep) - typically used with an under‑head shoulder for higher wrenchability.
- Series 2 (shallow) - used when greater head strength is required without a shoulder.
- Material / property classes: Steel 8.8, stainless A2‑70, non‑ferrous CU2/CU3 with associated mechanical requirements referenced to ISO 898‑1, ISO 3506‑1 and ISO 8839.
- Dimensional and tolerance control: Thread tolerances (6g), general metric threading per ISO 261 / ISO 965‑2, and product grade tolerances per ISO 4759‑1.
- Surface finish and coatings: Electroplating (ISO 4042), zinc‑flake coatings (ISO 10683), and passivation for stainless steel (ISO 16048).
- Quality & inspection: Surface discontinuities (ISO 6157‑1 / ISO 6157‑3) and acceptance inspection rules (ISO 3269).
- Designation examples: e.g. “Countersunk head screw ISO 7046‑2 – M5 × 20 – 8.8 – Z” (optionally include series number).
Applications
EN ISO 7046‑2:2011 is used by:
- Fastener manufacturers for product design and production controls.
- Design and mechanical engineers specifying countersunk fasteners in assemblies requiring flush heads and defined mechanical properties.
- Quality inspectors & procurement to verify conformity, material grade and coating requirements.
- OEMs in automotive, machinery, electronics, construction and consumer products where consistent head geometry, recess wrenchability and strength classes are critical.
The standard ensures interchangeability, predictable torque/wrenchability and adequate head strength across industries using countersunk flat head screws.
Related Standards
Keywords: EN ISO 7046‑2:2011, ISO 7046‑2:2011, countersunk flat head screws, cross recess, type H, type Z, property class 8.8, stainless steel screws, non‑ferrous metal screws, M2–M10, product grade A.
